U.S. patent application number 15/479829 was filed with the patent office on 2017-08-03 for edible coating for plant matter.
This patent application is currently assigned to Yissum Research Development Company of the Hebrew University of Jerusalem Ltd.. The applicant listed for this patent is Yissum Research Development Company of the Hebrew University of Jerusalem Ltd.. Invention is credited to Yonatan ELKIND, Tal MARMUR, Amos NUSSINOVITCH.
Application Number | 20170215445 15/479829 |
Document ID | / |
Family ID | 48325827 |
Filed Date | 2017-08-03 |
United States Patent
Application |
20170215445 |
Kind Code |
A1 |
NUSSINOVITCH; Amos ; et
al. |
August 3, 2017 |
EDIBLE COATING FOR PLANT MATTER
Abstract
Provided is a composition and methods for reducing the weight
loss and/or preserving the natural gloss of post-harvest edible
plant matter. In particular, the methods including applying to the
surface of the plant matter a composition including an edible wax
having a melting temperature below 70.degree. C.; a hydrocolloid; a
fatty acid; an emulsifier; and water, wherein said edible wax is
present in a weight percent ranging from about 10% to about 25% of
the total weight of the composition.
Inventors: |
NUSSINOVITCH; Amos;
(Rehovot, IL) ; MARMUR; Tal; (Tel Aviv, IL)
; ELKIND; Yonatan; (Rehovot, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Yissum Research Development Company of the Hebrew University of
Jerusalem Ltd. |
Jerusalem |
|
IL |
|
|
Assignee: |
Yissum Research Development Company
of the Hebrew University of Jerusalem Ltd.
Jerusalem
IL
|
Family ID: |
48325827 |
Appl. No.: |
15/479829 |
Filed: |
April 5, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14387242 |
Sep 23, 2014 |
9648890 |
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PCT/IL2013/050287 |
Mar 24, 2013 |
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15479829 |
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61617179 |
Mar 29, 2012 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A23V 2002/00 20130101;
A23B 7/16 20130101; A01N 3/04 20130101; A01N 3/00 20130101 |
International
Class: |
A23B 7/16 20060101
A23B007/16; A01N 3/04 20060101 A01N003/04 |
Claims
1.-44. (canceled)
45. A method for reducing the weight loss and preserving the
natural gloss of a post-harvest edible plant matter comprising the
step of applying to the surface of the plant matter a composition
comprising: a. an edible wax having a melting temperature lower
than about 70.degree. C.; b. a hydrocolloid polymer comprising a
non-gelling hydrocolloid polymer; c. a fatty acid; d. an
emulsifier; and e. water, thereby coating the edible plant matter
with the composition, which preserves the natural gloss of the
plant matter, wherein the edible wax is present in a weight percent
ranging from 10% to 25% of the total weight of said
composition.
46. The method of claim 45, further comprising the steps: i) Drying
the coating of the edible plant matter; and ii) Brushing the dried
coated edible plant matter.
47. The method of claim 45, wherein the edible plant matter is
selected from the group consisting of peppers, eggplants cherries,
berries, plums and persimmons.
48. The method of claim 45, wherein the edible wax is selected from
the group consisting of an animal wax, insect wax, microcrystalline
wax and paraffin wax.
49. The method of claim 48, wherein the edible wax is beeswax.
50. The method of claim 45 wherein the edible wax is present in a
weight percent ranging from about 15% to about 25% of the total
weight of the composition.
51. The method of claim 45, wherein the hydrocolloid polymer is
selected from the group consisting of locust bean gum (LBG), guar
gum, gum Arabic, xanthan gum, gum tragacanth, and mixtures
thereof.
52. The method of claim 45, wherein the hydrocolloid polymer is
present in a weight percent of up to 2% of the wet composition.
53. The method of claim 45, wherein the fatty acid is selected from
the group consisting of oleic acid, stearic acid, palmitic acid,
lauric acid, myristic acid, behenic acid, isostearic acid, and
mixtures thereof.
54. The method of claim 45, wherein the fatty acid is present in a
weight percent of about 0.2 to about 10% of the wet
composition.
55. The method of claim 45, wherein the emulsifier is selected from
the group consisting of morpholine, ammonia, lecithin, ethylene
glycol monostearate, ammonium lauryl sulfate, sodium
steroyl-2-lactylate, potassium oleate, propylene glycol
monostearate, sodium alkyl sulfate, polyglycol, and mixtures
thereof.
56. The method of claim 45, wherein the composition is applied to
the surface of the plant matter when the temperature of the
composition is from about 35.degree. C. to about 50.degree. C.
57. The method of claim 46, wherein the brushing is performed using
a brush comprising natural fibers.
58. The method of claim 46, wherein the brushing is performed for
about 1 to about 10 min.
59. The method of claim 46, wherein the brushing is performed at a
brushing speed of about 100 rounds per minute (rpm) to about 300
rpm.
60. The method of claim 45, wherein the composition comprises: a.
10%-25% (w/w) of the edible wax; b. up to 1% (w/w) of the
hydrocolloid polymer; c. 0.2%-10% (w/w) of the fatty acid; d.
0.1%-15% of the emulsifier; and e. 49%-89% (w/w) of water, wherein
the edible wax is beeswax.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a composition and methods
for extending the shelf life of edible plant matter by reducing
postharvest weight loss while preserving the external glossy
appearance of the plant matter, in particular fruits and
vegetables.
BACKGROUND OF THE INVENTION
[0002] Edible coatings, which are defined as thin layers of wax or
other substances applied to the surface of food, have been employed
for over 800 years to increase the shelf life of food. In the
United States, wax coatings have been utilized commercially since
1930s, when oranges were coated with melted paraffin waxes. These
early coatings were used to produce the appearance of a glossy
skin. In recent years, coatings have been used to preserve
attributes connected with fruit and vegetable quality and affording
shelf-life extension involving a decrease in weight loss and
respiration rate while providing glossy appearance and the possible
prevention of damage induced by insect penetration (Nussinovitch in
Modern biopolymer science: bridging the divide between fundamental
treatise and industrial application, Kasapis et al. (Eds.), New
York Academic Press, Elsevier Inc., 295-326, 2009).
[0003] Pepper fruit (Capsicum annuum L.) is naturally hollow and is
therefore characterized by limited water reservoir capacity.
Accordingly, the loss of small amounts of water may result in loss
of freshness and firmness, a reduction in fruit quality, shelf life
and market value (Maalekuu et al., J. Am. Soc. Horticult. Sci.,
130, 735-741, 2005). The major factor shortening the postharvest
life of bell peppers is water loss (Maalekuu et al., Adv.
Horticult. Sci., 17, 187-191, 2003). Once the fruit is harvested,
its tissue may rapidly dehydrate since the water potential (.PSI.),
which quantifies the water content of the surrounding air, is much
lower than that of the plant tissue thus causing the diffusion of
water from the fruit tissue to the environment. Consequently,
postharvest shriveling of the fruit occurs (Dijkink et al.,
Postharvest Biol. Technol., 32, 311-320, 2004). Flaccidity,
shriveling, wilting and decay are major problems that decrease
marketability and consumer acceptance of postharvest bell pepper
fruit. Flaccidity is also directly associated with the loss of
water during storage when respiration as well as diffusion of water
through the cuticle occur. Shriveling and wilting are processes
which are evident in water loss of 5% or more. Hence, reduction of
water loss, especially through diffusion through the cuticle, would
help maintain textural quality and external appearance of the fruit
thus improving its storage life.
[0004] Achieving water-saturated atmosphere around the fruit by
individual-seal, shrink-wrap or modified-atmosphere packaging (MAP)
has been employed. Bell peppers individually wrapped in plastic
film showed marked reduction in weight loss and softening, which
resulted in an extended shelf-life. Although individual-seal and
MAP appeared to reduce bell pepper fruit moisture loss, a number of
limitations inhibited commercial use. One limitation that has been
encountered is the development of aerobic microorganisms due to
water condensation caused by temperature fluctuations during
storage or transportation. It was noted that film wrapping
increased the incidence of bacterial soft rot in bell pepper
compared to non-wrapped peppers. It was also shown that
shrink-wrapped pepper developed higher populations of total aerobic
microorganisms, yeasts, and molds as compared to non-wrapped
peppers. Another limitation involved environmental apprehensions
about the use of plastic materials. Hence, replacement of plastic
films with edible or biodegradable materials is attractive from an
environmental perspective.
[0005] The most common methods used nowadays for reducing water
loss of postharvest fruit include lowering the temperature and/or
raising the relative humidity (RH) of the storage environment.
However, these storage environments can cause chilling injury,
enhance disease development and increased incidence of fruit decay.
In general, it is relatively difficult to preserve the quality of
postharvest bell peppers as compared to other fruits, due to the
peppers' sensitivity to low temperatures (<7.degree. C.), water
loss and rot development (Meir et al., Postharvest Biol. and
Technol., 5, 303-309 1995).
[0006] The application of edible coatings and films in fruits and
vegetables has received awareness worldwide for improvement of
postharvest life (Lerdthanangkul et al., J. Food Sci., 61, 176-179,
1996; Conforti et al., Food Chem. Toxicol., 67, 1360-1363, 2002;
Ozden et al., Euro. Food Res. Technol., 214, 320-326, 2002; Ayranci
et al., Food Chem., 87, 339-342, 2004; Beaulieu et al., Indust.
Crops and Products, 30, 271-275, 2009; Sabularse et al., Int. J.
Food Sci. Nutri., 60, 206-218, 2009). However, despite their
advantages, edible coatings for fruits can also adversely affect
their quality. For example, an edible coating used to reduce the
rate of water loss might interfere with fruit's respiration,
resulting in off-flavors (Park, Trends Food Sci. Technol., 10,
254-260, 1999; Chen et al., Food Hydrocolloids, 14, 561-568, 2000).
In addition, the surface gloss of food is a very important
parameter since it reflects on its quality in the eye of the
consumer. Bell peppers have very high natural gloss levels compared
to other fruits (Nussinovitch et al., Lebensmittel-Wissenschaft
und-Technologie, 29, 184-186, 1995). When very glossy surfaces,
such as those of red bell pepper, are treated with available
coating formulations, their natural shine may be diminished.
[0007] U.S. Pat. Nos. 6,299,915 and 6,068,867 to one of the
inventors of the present invention disclose a hydrocolloid
protective coating for food and/or agricultural products comprising
dried hydrocolloid gel, one or more natural compounds isolated from
the surface of said product or a compound substantially equivalent
thereto and other optional additives. The protective coating
provides improved protection of the product, thereby extending its
shelf-life.
[0008] U.S. Patent application No. 2004/0146617 and U.S. Pat. No.
7,222,455 disclose methods for suppressing cracking, stem browning,
and water loss in fruit or vegetables, such as cherries. The
methods comprise applying to fruit or vegetables an amount of a wax
emulsion comprising a matrix of complex hydrocarbons, one or more
emulsifying agents, and water. In some embodiments, the wax
emulsion comprises from about 0.125% to about 25% (weight/weight)
of carnauba wax, from about 0.1% to about 16% (weight/weight) of
oleic acid, and from about 0.03% to about 6% (weight/weight) of
morpholine, and from about 53% to about 99.7% (weight/weight) of
water.
[0009] Edible coatings on fruits can serve as gas or moisture
barriers. They can help diminish moisture loss, and/or reduce fruit
oxygen uptake from the environment and thus slow respiration.
Edible coatings have been reported to be effective on various kinds
of fruits and vegetables (U.S. Pat. Nos. 7,771,763 and 7,169,423).
Chitosan coating reduced weight loss, respiration rate, loss of
color, wilting, and fungal infection of bell pepper during storage
at 13.degree. C. and 20.degree. C. at 85% RH (El Ghaouth et al.,
Journal of Food Processing and Preservation, 15 (5), 359-368,
1991). Although several attempts have been made to design edible
coatings for bell pepper fruit, two main problems remained
unsolved. First, the coating provided only .about.4% reduction in
the weight loss of the coated commodity and second, the coating
reduced the natural gloss of the pepper.
[0010] There remains an unmet need in the art for an edible coating
of bell pepper which provides an extension of its shelf life
without impairing the natural gloss and taste thereof.
SUMMARY OF THE INVENTION
[0011] The present invention provides an edible hydrocolloid-wax
based composition useful for coating plant matter, particularly a
fruit or a vegetable having a high natural gloss and limited water
reservoir capacity, the composition comprising an edible wax having
a melting temperature below 70.degree. C., a hydrocolloid, a fatty
acid and an emulsifier. The composition of the present invention
extends the shelf life of plant matter coated with the composition
by reducing the plant's postharvest water loss while maintaining
the natural glossy appearance of the plant matter, preferably by
brushing or polishing the coated commodity.
[0012] The present invention is based in part on the unexpected
finding that coating of fruits and vegetables having natural gloss
with a composition comprising a wax having a melting temperature
below 70.degree. C. in an amount of at least 10% by weight of the
composition and less that 1% of a non-gelling hydrocolloid,
significantly reduced the postharvest water loss of the fruits and
vegetables, without affecting their taste and only minimally
affecting their natural gloss. Surprisingly, the compositions of
the present invention reduced the weight loss of coated peppers by
.about.50% as compared to non-coated peppers, thus doubling the
shelf life of coated peppers versus the non-coated ones. Although
the natural gloss of the peppers was typically reduced by about 25%
upon coating with the composition of the present invention,
brushing of the peppers restored their natural shine, while
maintaining the weight loss of the coated peppers significantly
lower than the weight loss of the uncoated peppers.
[0013] The compositions of the present invention are highly
advantageous as they restore the natural gloss of the post-harvest
fruits and vegetables as well as significantly reduce their water
loss and preserve their pleasing taste. It should be appreciated
that by virtue of the specific combination of the ingredients of
the compositions of the present invention, the three effects, i.e.,
restoration of the natural gloss, reduction of water loss, and
preservation of the taste of the post-harvest fruits and
vegetables, are achieved. Known coating compositions, although
capable of restoring the natural gloss of post-harvest fruits and
vegetables, often harm the pleasing taste of these fruits and
vegetables. Thus, the compositions of the present invention
provide, for the first time, means for coating post-harvest fruits
and vegetables which restores their natural gloss, reduces their
water loss, and preserves their pleasing taste, thereby extending
their shelf-life without compromising their appealing
appearance.
[0014] According to a first aspect, the present invention provides
a composition for coating edible plant matter having a natural
gloss, the composition comprising an edible wax having a melting
temperature below 70.degree. C., a hydrocolloid polymer, a fatty
acid, an emulsifier and water, wherein the edible wax is present in
an amount greater than 10% (w/w) and preferably equal or greater
than 15% (w/w) of the total weight of the wet coating composition,
wherein the amount of wax in the composition reduces the weight
loss of the plant due to water evaporation while maintaining the
pleasing taste and natural gloss of the plant matter as compared to
a plant matter coated with the same composition with edible wax in
an amount equal or lower than 10% or with an edible wax having a
melting temperatures higher than 70.degree. C. According to certain
embodiments, the edible wax should constitute about 10 to 25% (w/w)
of the weight of the wet coating composition and preferably between
15 and 25% (w/w) of the weight of the wet coating composition.
Accordingly, after drying the coating on the surface of the edible
plant, the edible wax will constitute between 55-80% (w/w) and
preferably between 60-80% (w/w) of the dried composition. It is to
be emphasized that after coating the plant matter, the
wax-hydrocolloid coating is left to dry, preferably at room
temperature. Preferably the drying of the coating results with a
hydrocolloid-wax coating having low water activity. Typically the
dried coating composition on the surface of the plant matter
comprises up to 10% of water, preferably up to 5% of water,
preferably, up to 3% of water and more preferably, up to 2% of
water. Each possibility represents a separate embodiment of the
invention.
[0015] According to some embodiments, the edible wax is having the
melting temperature of up to 75.degree. C. According to some
embodiments, the edible wax is having the melting temperature of
between 45 and 75.degree. C. According to some embodiments, the
edible wax is having the melting temperature of up to 70.degree. C.
According to some embodiments, the edible wax is having the melting
temperature of between 50 and 70.degree. C. According to some
embodiments, the edible wax is selected from animal wax, insect
wax, vegetable wax and mixtures thereof; each possibility
represents a separate embodiment of the invention. According to
some embodiments, the edible wax is an animal wax or an insect wax.
In some preferred embodiments, the animal or insect wax is beeswax.
In yet some other embodiments, the edible wax is a vegetable wax.
Non limiting examples of vegetable waxes include candelilla wax,
Japan wax, soy wax, bayberry wax, castor wax and mixtures thereof.
Each possibility represents a separate embodiment of the present
invention. According to still further embodiments, the edible wax
is selected from mineral waxes, such as, but not limited to montan
wax. According to yet a further embodiment, the edible wax is
selected from petroleum waxes. According to some embodiments,
petroleum waxes are selected from the group consisting of
microcrystalline wax, paraffin wax, and mixtures thereof. Each
possibility represents a separate embodiment of the present
invention.
[0016] According to some embodiments, the amount of edible wax
having a melting temperature below 75.degree. C. and preferably
below 70.degree. C. in the composition is sufficient to provide the
following parameters to an postharvest edible plant matter coated
with the composition:
[0017] 1. reduction of water loss;
[0018] 2. preservation of the pleasing taste with no off-flavors;
and
[0019] 3. restoration of the natural gloss,
as compared to an edible plant matter coated with a composition
containing less than 10% (w/w) of wax in the wet composition or an
edible plant matter coated with a composition containing same
amount of wax, wherein the wax is having a melting point above
75.degree. C.
[0020] The hydrocolloid polymer is typically present in an amount
lower than 2% (w/w), preferably lower than 1% of the total weight
of the wet coating composition. According to some embodiments, the
weight percent of the hydrocolloid polymer in the composition is
equal or lower than 0.5% (w/w), although the appropriate percentage
of the hydrocolloid polymer will be determined for the actual
hydrocolloid polymer used, as is well known to one of skill in the
art. After drying of the hydrocolloid-high wax composition, the
hydrocolloid polymer weight percentage will correspondingly rise
and, typically, will comprise a weight percent of 0.1 to 10% of the
dry composition. Importantly, the hydrocolloid used in compositions
and methods of the invention may influence the viscosity of the
composition however it does not gellify the wet composition. Thus,
according to some embodiments, the hydrocolloid polymer used may be
selected from a non-gelling hydrocolloid polymer, a gelling
hydrocolloid added to the composition in an amount lower than the
amount sufficient for gellifing the composition or a gelling
hydrocolloid added to the composition in the absence of a
sufficient amount of cross-linking agents (such as for example
potassium ions, or calcium ions) capable of causing the
gellification of the composition.
[0021] In some embodiments, the hydrocolloid is a non-gelling
hydrocolloid. In some embodiments, the non-gelling hydrocolloid is
selected from the group consisting of locust bean gum (LBG), guar
gum, xanthan gum and lambda-carrageenan. Each possibility
represents a separate embodiment of the present invention. In some
embodiments, the hydrocolloid is a gelling hydrocolloid used in an
amount lower than the amount necessary for gelling the compositions
of the present invention. Non-limiting examples of hydrocolloid
suitable for use in the compositions of the present invention
include: alginate, carrageenan, agar, agarose, arabinoxylan,
carboxymethylcellulose, cellulose, curdlan, gelatin, gellan,
.beta.-glucan, pectin, starch, gum arabic, gum tragacanth, tamarind
gum, fenugreek gum, cassia gum, tara gum. Each possibility
represents a separate embodiment of the present invention. In an
exemplary embodiment, the hydrocolloid is locust bean gum
(LBG).
[0022] Without being limited by any specific theory or mechanism of
action, the introduction of the hydrocolloid polymer into the wax
composition altered the ordered structure of the wax in the
composition after it has been dried on the surface of the plant
matter, permitting better gas exchange with the atmosphere and thus
resulting with a decrease in the production of off-flavor. As a
result of this non-uniform or "imperfect" coating, the respiration
of the coated plant matter is less disturbed and lower levels
(relative to commercial coatings based on wax) of ethanol and
acetaldehyde accumulate in the coated plant matter.
[0023] According to further embodiments, the fatty acid is
typically present in the wet composition in the amount ranging from
about 0.2 to about 10% (w/w). The emulsifier is typically present
in the wet composition in an amount ranging from about 0.1 to 15%
(w/w), preferably from about 0.1 to 10% (w/w), and more preferably
from about 0.1 to 5% (w/w), and even more preferably from about 0.1
to 3% (w/w). According to certain embodiments, the emulsifier
amount is lower than 2% (w/w) of the total weight of the wet
coating composition.
[0024] In some embodiments, the fatty acid comprises an aliphatic
chain of between 12 and 24 carbon atoms. In some embodiments, the
aliphatic chain is saturated. In some embodiments, the aliphatic
chain is un-saturated. Non limiting examples of fatty acids
suitable for the coating composition of the present invention
include oleic acid, stearic acid, palmitic acid, lauric acid,
myristic acid, behenic acid, and isostearic acid. Each possibility
represents a separate embodiment of the present invention. In an
exemplary embodiment, the fatty acid is oleic acid.
[0025] In certain embodiment, the emulsifier is an edible
emulsifier selected from non-ionic emulsifier, anionic emulsifier,
and mixtures thereof. Each possibility represents a separate
embodiment of the present invention. In some embodiments, the
emulsifier enables to composition to be in a liquid form at room
temperature. According to some embodiments, the emulsifier
facilitates the solubility of the wax in the composition. According
to some embodiments, the emulsifier served as a pH modifier of the
composition. Non limiting examples of suitable emulsifiers include
morpholine, ammonia, lecithin, ethylene glycol monostearate,
ammonium lauryl sulfate, sodium steroyl-2-lactylate, potassium
oleate, propylene glycol monostearate, sodium alkyl sulfate,
polyglycol. Each possibility represents a separate embodiment of
the present invention. In an exemplary embodiment, the emulsifier
is morpholine.
[0026] In additional embodiments, the composition may further
comprise a resin. In some embodiments, the resin may be selected
from the group consisting of shellac, copal, damar, elemi and
mixtures thereof. Each possibility represents a separate embodiment
of the present invention. According to some embodiments, when the
wax is a vegetable wax, an animal or insect derived resin (such as
shellac) is added to the composition, preferably at a weight ratio
of up to 5% of the total weight of the wet composition.
[0027] The composition of the present invention may further contain
additional substances selected from the group consisting of
antifoaming agents, preservative agents, adhesive agents,
cross-linking agents, plasticizers, and surface-tension reducing
agents. Each possibility represents a separate embodiment of the
present invention. Exemplary additional substances include, but are
not limited to polydimethylsiloxane (PDMS), potassium carbonate,
sodium bisulfite, sodium benzoate, sodium propionate, calcium
propionate, benzoic acid, potassium sorbate, polyethylene glycol,
glycerol, propylene glycol, sorbitol, mannitol, high laurate canola
oil (Laurical.TM.), Astral R and HUMKOTE.RTM.. Each possibility
represents a separate embodiment of the present invention.
[0028] According to some embodiments, the composition for coating
edible plant matter comprises: from about 10% to about 25% (w/w) of
edible wax, up to about 2% (w/w) of a hydrocolloid polymer, from
about 0.5 to about 5% (w/w) of the fatty acid, and from about 0.3
to about 5% (w/w) of the emulsifier in the wet composition.
According to some embodiments, the edible wax is beeswax. According
to some embodiments, the hydrocolloid polymer is locust bean gum.
According to some embodiment, the fatty acid is oleic acid.
According to some embodiments the emulsifier is morpholine.
[0029] According to some embodiments, the composition for coating
edible plant matter comprises: from about 10% to about 25% (w/w) of
edible wax, up to about 1% (w/w) of a hydrocolloid polymer, from
about 0.5 to about 5% (w/w) of the fatty acid, and from about 0.3
to about 5% (w/w) of the emulsifier in the wet composition.
According to some embodiments, the edible wax is beeswax. According
to some embodiments, the hydrocolloid polymer is locust bean gum.
According to some embodiment, the fatty acid is oleic acid.
According to some embodiments the emulsifier is morpholine.
[0030] According to some embodiments, the composition for coating
edible plant matter comprises: about 10%-25% (w/w) of beeswax; up
to about 1% (w/w) of hydrocolloid; about 0.2%-10% (w/w) of fatty
acid; about 0.1%-15% (w/w) of emulsifier; and about 49%-89% water,
of the total weight of the composition.
[0031] In one embodiment, the composition is applied to the edible
plant matter postharvest.
[0032] In another embodiment, the edible plant matter comprises a
fruit or a vegetable having naturally gloss appearance. In some
embodiments, the edible plant matter comprises a fruit or a
vegetable selected from the group consisting of peppers, eggplants
cherries, berries plums and persimmons. Each possibility represents
a separate embodiment of the present invention. In some
embodiments, the peppers are selected from the group consisting of
bell peppers, sweet peppers, chili peppers, and paprika peppers.
Each possibility represents a separate embodiment of the present
invention. In an exemplary embodiment, the plant matter is a bell
pepper. In another embodiment, the edible plant matter comprises a
fruit or a vegetable having small or limited water reservoir
capacity. In particular embodiments, the edible plant matter
comprises a fruit or a vegetable having from about 75% to about 95%
(w/w) water content.
[0033] According to another aspect the present invention provides a
method for reducing the weight loss and/or preserving the natural
gloss of a post-harvest edible plant matter comprising step of
applying to the surface of the plant matter a composition
comprising: an edible wax having a melting temperature lower than
70.degree. C.; a hydrocolloid polymer; a fatty acid; an emulsifier;
and water, thereby coating the edible plant matter, wherein the
edible wax is present in a weight percent ranging from 10% to 25%
of the wet composition and from 50% to 85% (w/w) of the dried
composition.
[0034] According to some embodiments, the composition is applied to
the surface of the plant matter by rubbing the composition onto the
surface of the plant, possibly by using of rubber gloves, dipping
or immersing the edible plant matter in the composition, spraying
the composition onto the edible plant matter, pouring the
composition onto the plant matter, possibly when the plant matter
is moving on a conveyor belt. Each possibility represents a
separate embodiment of the present invention.
[0035] According to some embodiments, the application of the
composition of the present invention to the surface of the plant
matter is performed at room temperature (25.degree.
C..+-.10.degree. C.). According to some embodiments, the
composition is applied to the surface of the plant matter and/or to
the stem of the plant matter when the temperature of the
composition is between 35.degree. C. to 70.degree. C., preferably
at a temperature of between 35.degree. C. to 50.degree. C. After
applying the hydrocolloid-wax composition to the surface of the
plant matter, the coating is left to dry on the surface of the
plant matter, preferably at room temperature.
[0036] According to some embodiments, the method of the invention
further comprises the step of brushing the coated edible plant
matter. The brushing of the coated plant matter restores the glossy
appearance of the plant matter to at least 80% of the natural gloss
of uncoated plant matter, preferably to at least 85% of the natural
gloss of the uncoated plant matter and most preferably to about 90%
of the natural gloss of the uncoated plant.
[0037] Polishing or brushing the coating decreased its thickness
and induced the redistribution of the wax on the surface of the
plant matter which increased the gloss values of the coated plant
matter. Polishing of a plant matter coated with a hydrocolloid-wax
composition wherein the wax had a melting temperature below
70.degree. C. (e.g. beeswax) resulted in a glossier appearance as
compared to a plant matter coated with a hydrocolloid-wax
composition wherein the wax has a melting temperature above
70.degree. C. (e.g. carnauba wax). Without being limited by any
theory or mechanism of action, the glossier appearance may result
from the greater redistribution of the wax due to its relative
softness.
[0038] According to some embodiments, the coating thickness prior
to brushing is between 20 and 50 .mu.m thick. According to some
embodiments, the coating thickness is reduced by up to 50% upon
brushing. According to some embodiments, the brushing of the coated
plant matter is performed using a brush comprising natural fibers
such as horse hair fibers. According to some embodiments, the
brushing of the coated plant matter is performed using a brush
comprising synthetic fibers such as nylon or polyethylene fibers.
According to some embodiments the brush comprises horse hair
fibers. According to some embodiments, the coated plant is brushed
for up to 20 minutes, preferably between 1-10 minutes, at a
brushing speed of about 100 to 300 rpm.
[0039] According to some embodiments, the method of the invention
provides the extension of shelf life of edible plant matter by
reducing the extent of weight loss during storage. According to
some embodiments, the weight loss of a plant matter coated with the
composition of the invention is reduced by at least 20%, preferably
by at least 30%; preferably by at least 40%; and most preferably by
about 50% as compared to an uncoated plant matter under same
storage conditions. According to some embodiments, the method of
the present invention provides the extension of the shelf life of
the edible plant matter for between several days to several weeks
beyond the shelf life of uncoated edible plant matter under the
same storage conditions. According to some embodiments, the shelf
life of an edible plant matter coated with the formulation of the
invention is doubled as compared to the shelf life of an uncoated
plant matter under the same storage conditions.
[0040] The methods of the present invention are particularly
advantageous for the coating of edible plant matter comprising
fruits or vegetables having small water reservoir capacity and/or
to fruits or vegetables having a natural glossy appearance such as
for example peppers, eggplants and persimmons. According to some
currently preferred embodiments, the methods of the present
invention suitable for coating peppers.
[0041] According to some additional preferred embodiments, the
present invention provides a method for reducing the weight loss
and/or preserving the natural gloss of a post-harvest edible plant
matter comprising step of applying to the surface of the plant
matter a composition comprising: beeswax; present in a weight
percent ranging from 10% to 25% of the wet composition and from 50%
to 85% (w/w) of the dried composition, a hydrocolloid polymer; a
fatty acid and an emulsifier. According to yet additional preferred
embodiments, the present invention provides a method for reducing
the weight loss and/or preserving the natural gloss of a
post-harvest pepper (such as a bell-pepper) comprising the step of
applying to the surface of the pepper a composition comprising:
beeswax; present in a weight percent ranging from 10% to 25% of the
wet composition and from 50% to 85% (w/w) of the dried composition,
a hydrocolloid polymer; a fatty acid and an emulsifier.
[0042] In another aspect, the invention provides a method for
preparation of the hydrocolloid-high wax compositions useful for
the coating of a plant matter, particularly fruit or vegetable
having limited water reservoir capacity and high natural gloss, the
method comprising the steps of: a) adding a hydrocolloid to
preheated water having a temperature in the range from about
55.degree. C. to about 95.degree. C., more preferably from about
75.degree. C. to about 85.degree. C.; b) adding a fatty acid and an
emulsifier to the mixture obtained in step a; c) adding molten wax
to the mixture obtained in step (b).
[0043] Further embodiments and the full scope of applicability of
the present invention will become apparent from the detailed
description given hereinafter. However, it should be understood
that the detailed description and specific examples, while
indicating preferred embodiments of the invention, are given by way
of illustration only, since various changes and modifications
within the spirit and scope of the invention will become apparent
to those skilled in the art from this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] FIGS. 1A-1B. Brushing apparatus. (FIG. 1A) Engine (1),
rotating brush (2), pepper/plate sample (3), lab jack adjusting
handle (4); (FIG. 1B) Engine (1), coupling (2), aluminum tank (3),
pepper (4), cylindrical brush (5), bearing (6).
[0045] FIGS. 2A-2C. Research Grade Leica DMLM micrographs of
uncoated (FIG. 2A), carnauba wax formulation-coated (FIG. 2B) and
carnauba wax formulation-coated & brushed (FIG. 2C) red bell
pepper samples.
[0046] FIG. 3. Retained weight (%) in red bell peppers during 7
days of storage. Uncoated ( ), coated with beeswax formulation
(.box-solid.), coated with beeswax formulation and then brushed
(.quadrature.), coated with carnauba wax formulation
(.tangle-solidup.), coated with carnauba wax formulation and then
brushed (.DELTA.).
[0047] FIG. 4. Images of uncoated, beeswax formulation-coated, and
beeswax formulation-coated and brushed red bell peppers after 1 day
(panel A), 1 week (panel B) and 2 weeks (panel C) of storage at
room temperature.
[0048] FIGS. 5A-5C. Light micrographs of uncoated (FIG. 5A),
beeswax formulation-coated (FIG. 5B), and beeswax
formulation-coated and brushed (FIG. 5C) red pepper samples
(magnification .times.20).
[0049] FIGS. 6A-6B. (FIG. 6A) Average gloss of aluminum plate
before coating (left), after coating with carnauba wax formulation
(middle) and after brushing the coated plate for five minutes using
a horse hair brush (right) at five different speeds; (FIG. 6B)
Average gloss of aluminum plate after coating with carnauba wax
formulation (left) and after brushing the coated plate for five
minutes using a horse hair brush (right) at five different speeds.
The letter above each column represents significant differences
between treatments
[0050] FIGS. 7A-7D. SEM micrographs of the three types of brush
fiber samples. (FIG. 7A) Polyethylene .times.2,200, (FIG. 7B) soft
nylon .times.2,200, (FIG. 7C) horse hair .times.1,200, (FIG. 7D)
horse hair .times.2,200.
[0051] FIG. 8. Average gloss grades of uncoated, carnauba wax
formulation-coated and carnauba wax formulation-coated &
brushed red peppers that were ranked by the sensory evaluation
panel.
[0052] FIG. 9. Gloss of uncoated, beeswax formulation-coated, and
beeswax formulation-coated and brushed red bell peppers at
60.degree. and 85.degree. angles. Different letters within the same
angle indicate significant differences between treatments
(p.ltoreq.0.01).
[0053] FIG. 10. Roughness (R.sub.a) of uncoated (left), beeswax
formulation-coated (middle), and beeswax formulation-coated and
brushed (right) red bell peppers during 7 days of storage at room
temperature. Different letters within a sampling day indicate
significant differences between treatments (p.ltoreq.0.0001).
[0054] FIGS. 11A-11B. Surface-roughness profile of uncoated,
beeswax formulation-coated, and beeswax formulation-coated and
brushed red bell peppers after 1 (FIG. 11A) and 7 (FIG. 11B) days
of storage at room temperature.
[0055] FIG. 12. Deformation at puncture during storage of uncoated
(left), beeswax formulation-coated (middle), and beeswax
formulation-coated and brushed (right) red bell peppers. Different
letters within a sampling day indicate significant differences
between treatments (p.ltoreq.0.001).
DETAILED DESCRIPTION OF THE INVENTION
[0056] The present invention provides an edible hydrocolloid-wax
based composition useful for coating a plant matter, particularly a
fruit or a vegetable having a high natural gloss and limited water
reservoir capacity, the composition comprising an edible wax having
a melting temperature below 70.degree. C., a hydrocolloid, a fatty
acid and an emulsifier. The composition of the present invention
extends the shelf life of a plant matter coated with the
composition by reducing the plant's postharvest water loss while
maintaining the natural glossy appearance of the plant matter,
preferably by brushing or polishing the coated commodity.
[0057] The term "fruit or vegetable having a small water reservoir"
as used herein refers to fruits or vegetables having from about 75%
to about 90% (w/w) water content, for example, about 75%, about
80%, about 85%, or about 90% weight percent water. Each possibility
represents a separate embodiment of the present invention. Fruit
and vegetables having a small water reservoir include also hollow
fruits or vegetables such as peppers having a small water
reservoir. Additional non-limiting examples of such fruits and
vegetables are eggplants, persimmons, grapes, mangos and
papaya.
[0058] The term "glossy appearance", as used herein, refers to a
physical property which is characteristic of the visual appearance
of a plant matter and is very important for consumer acceptance.
More specifically, gloss refers to the ability of the surface of a
plant matter to reflect incident light giving a "shiny" or "glossy"
appearance. Gloss can be measured in a variety of ways both
visually and instrumentally. Specifically, gloss may be measured by
a glossmeter which provides a quantifiable way of measuring gloss
intensity. The measurement results of a glossmeter are related to
the amount of reflected light from a black glass standard with a
defined refractive index. The ratio of reflected to incident light
for the specimen, compared to the ratio for the gloss standard, is
recorded as gloss units. Typically, gloss may be measured at three
measurement angles, i.e. 20.degree., 60.degree. or 85.degree.
usually the angle is selected for a particular application based on
the anticipated gloss range. As used herein, plant matter with
natural gloss refers to a plant matter having a gloss value
measured at 60.degree. from a flat surface of 5 GU (gloss units) or
greater, alternatively 7 GU or greater, alternatively at least 10
GU. According to some embodiments, glossy appearance refers to
60.degree. gloss value of 12 GU or greater.
"Gloss Units (GU)" is a scaling based on a highly polished
reference black glass standard with a defined refractive index
having a specular reflectance of 100 GU at the specified coincident
angle. This standard is used to establish an upper point
calibration of 100 with the lower end point established at 0 on a
perfectly matt surface.
[0059] The terms "restoring the glossy appearance", "restoring the
gloss", "maintaining the glossy appearance" and "maintaining the
gloss", as used herein, refer to achieving a gloss value which is
at least 80% of the natural gloss of uncoated plant matter.
[0060] It has been previously shown that by applying a composition
comprising a wax and a hydrocolloid on the surface of citrus
fruits, postharvest water weight loss can be significantly reduced
(S. Chen, A. Nussinovitch, Food hydrocolloids 14, 561-568, 2000).
Compositions comprising a non-gelling hydrocolloid with edible wax,
coated on a citrus surface provided a coating which decreased water
evaporation rate while preventing fermentation and the formation of
off-flavors. However, application of such composition to fruits or
vegetables, having a naturally glossy appearance, impaired the
natural gloss of the plant matter and reduced commercial
attractiveness thereof.
[0061] It has now been found that increasing the edible wax
concentration in the coating composition allowed an only minimal
reduction in natural gloss of the coated plant matter. Performing
appropriate brushing after applying the hydrocolloid-high wax
compositions of the present invention restored the glossy
appearance of the plant matter. Therefore, the composition of the
present invention overcomes the disadvantages of known compositions
by using a hydrocolloid-high wax coating which reduces water weight
loss but does not impair the gloss and taste of edible plant
matter.
[0062] The composition of the present invention comprises an edible
wax. According to some embodiments, the composition of the present
invention comprises at least 10% (w/w) of the edible wax. According
to some embodiments, the composition comprises between about 10%
and about 25% (w/w) edible wax, and preferably between about 15%
and about 25%. For example about 15, about 16, about 17, about 18,
about 19, about 20, about 21, about 22, about 23, about 24, or
about 25 weight percent edible wax. Each possibility represents a
separate embodiment of the present invention. The term "edible wax"
as used herein refers to synthetic waxes that are suitable for
human consumption, such as food-grade petroleum products, or
natural waxes obtained from plants, insects (similar to honey bees)
or animals. Non-limiting examples of vegetable waxes include
candelilla wax, Japan wax, soy wax, castor wax, bayberry wax and
mixtures thereof. Each possibility represents a separate embodiment
of the present invention. Preferably, the edible wax is selected
from animal or insect waxes such as beeswax. The edible wax may
further be selected from mineral waxes, such as, but not limited to
montan wax or from petroleum waxes, such as but not limited to,
microcrystalline wax and paraffin wax. Preferably, the edible wax
is selected from waxes having a melting temperature lower than
70.degree. C., such as, but not limited to, beeswax having a
melting temperature of between 62-64.degree. C.
[0063] According to some embodiments, the wax comprises a mixture
of waxes. According to some embodiments the mixture of waxes
comprises at least one wax having a melting temperature lower than
70.degree. C. According to some embodiments, a mixture of waxes
comprises at least one wax having a melting temperature lower than
70.degree. C. and at least one wax having a melting temperature
above 70.degree. C. According to some embodiments, the mixture of
waxes comprises one or more waxes having a melting temperature
lower than 70.degree. C. present at a weight percent of at least
50% (w/w) of the total weight of waxes in the composition;
alternatively, at least 60% (w/w) of the total weight of waxes in
the composition; alternatively, at least 70% (w/w) of the total
weight of waxes in the composition; alternatively, at least 80%
(w/w) of the total weight of waxes in the composition;
alternatively, at least 90% (w/w) of the total weight of waxes in
the composition; alternatively, at least 95% (w/w) of the total
weight of waxes in the composition; alternatively, at least 98%
(w/w) of the total weight of waxes in the composition;
alternatively, at least 99% (w/w) of the total weight of waxes in
the composition. Non limiting examples of waxes having a melting
temperature above 70.degree. C. include: carnauba wax, rice bran
wax, ouricury wax and esparto wax. According to one embodiment, the
wax may comprise a mixture of beeswax and carnauba wax. According
to another embodiment, the wax may comprise a mixture of beeswax
and carnauba wax in a weight ratio ranging from about 1:10 to about
10:1.
[0064] The composition for coating edible plant matter comprises a
hydrocolloid. The term "hydrocolloids" as used herein refers to
water soluble polymers, of vegetable, animal, microbial or
synthetic origin, that generally contain many hydroxyl groups and
are capable of increasing the viscosity of the composition. The
hydrocolloids of the present invention allow thickening of aqueous
systems, without gelling thereof.
According to some embodiments, the hydrocolloid is a non-gelling
hydrocolloid. According to some embodiments, the hydrocolloid may
be a gelling hydrocolloid added to the composition at a
concentration which is low enough so as not to cause the
gellification of the composition. According to some embodiments,
gelling hydrocolloids may be added at concentrations lower than
0.2% (w/w) of the wet composition, preferably, lower than 0.1%
(w/w) of the weight of the wet composition. However, the
appropriate percentage of the hydrocolloid polymer will be
determined for the actual hydrocolloid used, as is well known to
one of skill in the art. Suitable non-gelling hydrocolloids
include, but are not limited to, locust bean gum (LBG), guar gum,
xanthan gum, and gum tragacanth. Each possibility represents a
separate embodiment of the present invention. Other non-gelling
hydrocolloids within the scope of the present invention include,
but are not limited to, lambda-carrageenan alkyl and
hydroxyalkylcellulose, carboxymethyl cellulose, gum arabic, gum
karaya, hydroxyethyl cellulose, hydroxypropylcellulose, tamarind
gum and hydrolyzed gelatin. Additional hydrocolloids usable in the
compositions of the present invention include, but are not limited
to, tamarind gum, fenugreek gum, cassia gum, and tara gum. Suitable
gelling hydrocolloids that may be used in non-gelling
concentrations include but not limited to, agar, agarose, alginate,
chitin, chitosan, curdlan, gellan, konjac mannan, pectin, and
carrageenan.
[0065] Without being bound by any theory or mechanism of action, it
is contemplated that the hydrocolloid increases the viscosity of
the composition and forms discontinuity in the dried wax-based
layer coating the surface of the plant matter, thereby preventing
fermentation (e.g. anaerobic fermentation) and the formation or
accumulation of off-flavors. The hydrocolloid may also serve as
resistor to gases diffusion.
[0066] The composition of the present invention comprises a fatty
acid. According to some embodiments, the fatty acid comprises an
aliphatic chain of between 12 and 24 carbon atoms. Suitable fatty
acids within the scope of the present invention include, but are
not limited to, oleic acid, stearic acid, palmitic acid, lauric
acid, myristic acid, behenic acid, and isostearic acid. Each
possibility represents a separate embodiment of the present
invention. Without being bound by any theory or mechanism of
action, the fatty acid serves as a hydrophobic reservoir that
decreases the water loss by evaporation thereby affording a
decrease of the water evaporation rate. The fatty acid may further
liquefy the formulation and enhance the glossy appearance of the
plant matter when combined with the edible waxes of the
composition.
[0067] According to some embodiments, the composition comprises
from about 0.2 to about 10% (w/w) of a fatty acid. According to
some embodiments, the composition comprises from about 0.2 to about
5% (w/w) of fatty acid. According to some embodiments, the
composition comprises from about 0.5 to about 4% (w/w) of fatty
acid. According to some embodiments, the composition comprises from
about 0.5 to about 3% (w/w) of fatty acid. According to some
embodiments, the composition comprises from about 0.5 to about 2%
(w/w) of fatty acid. Each possibility represents a separate
embodiment of the present invention.
[0068] The composition of the present invention further comprises
an emulsifier. Typically, the composition comprises from about 0.2
to about 15% (w/w) emulsifier. According to some embodiments, the
composition comprises between 0.2 and 10%. According to some
embodiments, the composition comprises between 0.2 and 5% of an
emulsifier. According to some embodiments, the composition
comprises between 0.5 and 3% of an emulsifier. Suitable emulsifiers
include, but are not limited to edible non-ionic or anionic
emulsifiers, such as morpholine, ammonia, lecithin, ethylene glycol
monostearate, ammonium lauryl sulfate, sodium steroyl-2-lactylate,
potassium oleate, propylene glycol monostearate, sodium alkyl
sulfate, sodium oleate, sorbitan monostearate, oleic acid, and
polyglycol. Each possibility represents a separate embodiment of
the present invention. In certain embodiments, the emulsifier is a
nitrogen containing emulsifier, e.g. morpholine.
[0069] The composition of the present invention can optionally
contain additional substances selected from the group consisting of
antifoaming agents, preservative agents, adhesive agents,
cross-linking agents, plasticizers, and surface-tension reducing
agents. Each possibility represents a separate embodiment of the
present invention. Exemplary additional substances include, but are
not limited to polydimethylsiloxane (PDMS), potassium carbonate,
sodium bisulfite, sodium benzoate, sodium propionate, calcium
propionate, benzoic acid, potassium sorbate, polyethylene glycol,
glycerol, propylene glycol, sorbitol, mannitol, and HUMKOTE.RTM..
Each possibility represents a separate embodiment of the present
invention.
[0070] According to the principles of the present invention, the
addition of additional substances to the composition is performed
in order to obtain a wax-hydrocolloid composition having desired
properties such as, but not limited to desired viscosity,
plasticity, hydrophobicity, shine, pH, and the like. For example,
the additives may provide other characteristics, functions, or
properties to the composition of the present invention, such as,
but not limited to, disinfectant properties.
[0071] According to another aspect the present invention provides a
method for reducing the weight loss and/or preserving the natural
gloss of a post-harvest edible plant matter comprising step of
applying to the surface of the plant matter a composition
comprising: an edible wax having a melting temperature lower than
70.degree. C.; a hydrocolloid polymer; a fatty acid; an emulsifier;
and water, thereby coating the edible plant matter, wherein the
edible wax is present in a weight percent ranging from 10% to 25%
of the wet composition and from 50% to 85% (w/w) of the dried
composition. According to some embodiments, the composition
comprises: 10%-25% (w/w) of beeswax; up to 1% (w/w) of
hydrocolloid; 0.2%-10% (w/w) of a fatty acid; 0.1%-15% (w/w) of an
emulsifier; and 49%-89% of water of the total weight of the
composition. According to other embodiments, the composition
comprises: 15%-25% (w/w) of beeswax; up to 1% (w/w) of
hydrocolloid; about 0.2%-3% (w/w) of a fatty acid; about 0.1%-5%
(w/w) of an emulsifier; and 65%-84% water, of the total weight of
the composition.
[0072] According to some embodiments, the composition is applied to
the surface of the plant matter by rubbing the composition onto the
surface of the plant, possibly by using of rubber gloves, dipping
or immersing the edible plant matter in the composition, spraying
the composition onto the edible plant matter, pouring the
composition onto the plant matter, possibly when the plant matter
is moving on a conveyor belt. Each possibility represents a
separate embodiment of the present invention.
[0073] The composition may be applied at a certain temperature to
afford a substantially uniform coating of the fruit or vegetable.
According to some embodiments, the application of the composition
of the present invention to the surface of the plant matter is
performed at room temperature (25.degree. C..+-.10.degree. C.).
According to some embodiments, the composition is applied to the
surface of the plant matter when the temperature of the composition
is between 35.degree. C. to 70.degree. C., preferably at a
temperature of between 35.degree. C. to 50.degree. C. It will be
recognized by one of skill in the art that the composition of the
present invention is more easily applied in a liquid form.
Accordingly, the composition may be applied at a temperature in
which the edible wax is liquefied or partly liquefied.
[0074] After applying the hydrocolloid-wax composition to the
surface of the plant matter, the coating is left to dry on the
surface of the plant matter.
The present invention further provides a method of maintaining the
external glossy appearance of the uncoated edible plant matter or
restoring the external glossy appearance of the coated edible plant
matter, the method comprising brushing the coated edible plant
matter. It is contemplated that brushing is performed to increase
the glossy appearance of the coated edible plant matter as compared
to the glossy appearance of the coated unbrushed edible plant
matter. The brushing of the coated plant matter restores the glossy
appearance of the plant matter to at least 80% of the natural gloss
of uncoated plant matter, preferably to at least 85% of the natural
gloss of the uncoated plant matter and most preferably to about 90%
of the natural gloss of the uncoated plant.
[0075] Without being bound by any theory or mechanism of action,
polishing or brushing the coating decreases its thickness and
induced the redistribution of the wax on the surface of the plant
matter which increases the gloss values of the coated plant matter.
According to some embodiments, the polishing of a coating
comprising a wax having a melting temperature below 70.degree. C.,
results with greater wax redistribution due to the wax's relative
softness and results with a glossier appearance than the gloss
obtained when a coating formulation comprises wax having a higher
melting point.
[0076] According to some embodiments, the coating thickness prior
to brushing is between 20 and 50 .mu.m thick. According to some
embodiments, the coating thickness is reduced by up to 50% upon
brushing; accordingly the coating thickness after brushing is
between about 10 to about 40 .mu.m. According to some embodiments,
the brushing of the coated plant matter is performed using a brush
comprising natural fibers or bristles such as horse hair fibers,
goat hair fibers, boar hair or bristles or pig hair. According to
some embodiments, the brushing of the coated plant matter is
performed using a brush comprising synthetic fibers such as nylon,
polyethylene or rayon fibers. According to some embodiments, the
brushing of the coated plant matter is performed using non-woven
fabric or a non-woven high loft media. It is to be emphasized that
the step of brushing the coated plant-matter is performed only
after the hydrocolloid-wax coating composition has been fully
dried. Drying of the coated plant matter is typically performed by
allowing the coated plant matter to dry at room temperature.
Alternatively, the coating composition may be left to dry or
actively dried after its application to the surface of the plant
matter by any method or under any conditions known in the art at
the decision of the one skilled in the art. According to some
embodiments the coated plant is brushed for up to 20 minutes,
preferably between 1-10 minutes, at any brushing speed preferably
from about 100 to 300 rpm, for example about 100 rpm, about 150
rpm, about 200 rpm, about 250 rpm, or about 300 rpm. Each
possibility represents a separate embodiment of the present
invention.
According to some embodiments, the method of the invention provides
the extension of shelf life of edible plant matter by reducing the
extent of weight loss during storage. According to some
embodiments, the method of the present invention provides the
extension of the shelf life of the edible plant matter for between
several days to several weeks beyond the shelf life of uncoated
edible plant matter under the same storage conditions. According to
some embodiments, the shelf life of an edible plant matter coated
with the formulation of the invention is at least 20% higher than
the shelf life of an uncoated plant matter under the same storage
conditions; alternatively, at least 25% higher, alternatively at
least 30% higher; alternatively at least 35% higher, alternatively
at least 40% higher. According to some embodiments, the shelf life
of an edible plant matter coated with the formulation of the
invention is doubled as compared to the shelf life of an uncoated
plant matter under the same storage conditions The methods of the
present invention are particularly advantageous for the coating of
edible plant matter comprising fruits or vegetables having small
water reservoir capacity and/or to fruits or vegetables having a
natural glossy appearance such as for example peppers, eggplants
and persimmons. According to some currently preferred embodiments,
the methods of the present invention suitable for coating
peppers.
[0077] According to some additional preferred embodiments, the
present invention provides a method for reducing the weight loss
and/or preserving the natural gloss of a post-harvest edible plant
matter comprising step of applying to the surface of the plant
matter a composition comprising: beeswax; present in a weight
percent ranging from 10% to 25% of the wet composition and from 50%
to 85% (w/w) of the dried composition, a hydrocolloid polymer; a
fatty acid and an emulsifier. According to yet additional preferred
embodiments, the present invention provides a method for reducing
the weight loss and/or preserving the natural gloss of a
post-harvest pepper (such as a bell-pepper) comprising the step of
applying to the surface of the pepper a composition comprising:
beeswax; present in a weight percent ranging from 10% to 25% of the
wet composition and from 50% to 85% (w/w) of the dried composition,
a hydrocolloid polymer; a fatty acid and an emulsifier.
[0078] In another aspect, the invention provides a method for
preparation of the hydrocolloid-high wax compositions useful for
the coating of a plant matter, particularly fruit or vegetable
having limited water reservoir capacity and high natural gloss, the
method comprising the steps of:
[0079] a) Adding a hydrocolloid to preheated water having a
temperature in the range from about 55.degree. C. to about
95.degree. C., preferably from about 75.degree. C. to about
85.degree. C.;
[0080] b) Adding a fatty acid and an emulsifier to the mixture
obtained in step a;
[0081] c) Adding molten wax to the mixture obtained in step b.
[0082] According to some embodiments, step a is typically followed
by vigorously stirring the solution for any length of time until
the hydrocolloid is solubilized, typically between about 1 minute
and about 30 minutes. The method further comprises adding a fatty
acid and an emulsifier to the hot hydrocolloid solution. The
preparation is followed by adding a previously molten wax to the
solution and homogenizing the composition for any length of time,
typically between about 1 minute and about 15 minutes. The
composition is further stirred for the elimination of foam.
According to some embodiments, the formation of foam may be reduced
or even prevented by the addition of anti-foaming agents to the
composition. According to some embodiments, the viscosity of the
composition obtained is from about 5 to about 500 cP at a shear
rate of 70 s.sup.-1 and at a temperature of 25.degree. C.
[0083] According to some embodiments, the wax-hydrocolloid
composition is an emulsion. According to some embodiments, the
wax-hydrocolloid composition is an emulsion stabilized by the
emulsifier. According to currently preferred embodiments, the
wax-hydrocolloid composition is an emulsion stabilized by
morpholine. According to some embodiments, the emulsion is a oil in
water emulsion.
[0084] As used herein and in the appended claims the singular forms
"a", "an" and "the" include plural references unless the content
clearly dictates otherwise. It should be noted that the term "and"
or the term "or" is generally employed in its sense including
"and/or" unless the content clearly dictates otherwise.
[0085] The following examples are presented in order to more fully
illustrate some embodiments of the invention. They should, in no
way be construed, however, as limiting the broad scope of the
invention. One skilled in the art can readily devise many
variations and modifications of the principles disclosed herein
without departing from the scope of the invention.
Examples
Example 1: Materials and Methods
Formulations
[0086] The formulations comprising hydrocolloid and edible wax are
presented in Table 1.
TABLE-US-00001 TABLE 1 Hydrocolloid-high wax composition
formulations Locust Wax bean gum Oleic acid Morpholine Shellac PDMS
Water Formulation (% w/w) (% w/w) (% w/w) (% w/w) (% w/w) (% w/w)
(% w/w) Carnauba 1 10 0.50 1.8 2.4 2.0 -- 83.3 2 15 0.50 1.8 2.4
3.0 -- 77.3 3 18 0.45 1.6 2.2 3.6 -- 74.2 3A 18 0.50 1.6 2.2 3.6
0.01 74.1 Beeswax 4 5 0.50 1.8 0.25 -- -- 92.4 5 10 0.50 1.8 0.50
-- -- 87.2 6 15 0.50 1.8 0.75 -- -- 81.9 7 20 0.50 1.8 1.00 -- --
76.7
[0087] Formulations 1-3A comprise carnauba as an edible wax,
wherein the wax weight percent in the compositions is in the range
from 10 to 18% (w/w). Formulations 4-7 comprise beeswax as an
edible wax, wherein the wax weight percent in the compositions is
in the range from 5 to 20% (w/w).
Hydrocolloid-High Wax Formulation Preparation
Formulation 2 (Carnauba)
[0088] Locust bean gum (LBG; Sigma Chemical Co., St. Louis, Mo.)
was added at 0.5% (w/w) to 77.3% (w/w) preheated water (85.degree.
C.) for 15 min with vigorous stirring. Oleic acid (1.8% w/w)
(Aldrich Chemical Company, Inc., Milwaukee, Wis.) and 2.4% (w/w)
morpholine (Sigma) were also added to the hot mixture, followed by
the addition of 15 (w/w) of previously molten (95.degree. C.)
carnauba wax (Aldrich) and 3% (w/w) shellac (Safe-Pack, Inc., Kfar
Saba, Israel).
Formulation 3 (Carnauba)
[0089] The coating formulation was prepared by adding Locust Bean
Gum (LBG, Sigma) at (0.45%, w/w) to (74%, w/w) preheated water
(85.degree. C.) for 15 minutes with vigorous stirring. Oleic acid
(1.6%, w/w) (Aldrich Chemical Company, Inc.) and morpholine (2.2%,
w/w) (Sigma Chemical Co, St. Louis, Mo.) were added to the mixture,
followed by the addition of 18% (w/w) of previously molten
(95.degree. C.) carnauba wax (Aldrich Chemical Company, Inc.,
Milwaukee, Wis.) and 3.6% (w/w) shellac (Safe-Pack, Inc., Kfar
Saba, Israel). The formulation was homogenized by ultra-turrax
(T-25, Janke and Kunkel, Germany) at 24,000 rounds per minute (rpm)
for 5 minutes and stirred until no foam was observed.
Formulation 3A (Carnauba)
[0090] The coating formulation was prepared by adding Locust Bean
Gum (LBG, Sigma) at (0.5%, w/w) to (74%, w/w) preheated water
(85.degree. C.) for 15 minutes with vigorous stirring. Oleic acid
(1.6%, w/w) (Aldrich Chemical Company, Inc.) and morpholine (2.2%,
w/w) (Sigma Chemical Co, St. Louis, Mo.) were added to the mixture,
followed by the addition of 18% (w/w) of previously molten
(95.degree. C.) carnauba wax (Aldrich Chemical Company, Inc.,
Milwaukee, Wis.) and 3.6% (w/w) shellac (Safe-Pack, Inc., Kfar
Saba, Israel). 0.01% (w/w) polydimethylsiloxane (PDMS; Dow Corning,
Belgium) was added to the formulation. The formulation was
homogenized by ultra-turrax (T-25, Janke and Kunkel, Germany) at
24,000 rounds per minute (rpm) for 5 minutes and stirred until no
foam was observed.
Formulation 6 (Beeswax)
[0091] Locust bean gum (LBG; Sigma Chemical Co., St. Louis, Mo.)
was added at 0.5% (w/w) to 82% (w/w) preheated water (85.degree.
C.) for 15 min with vigorous stirring. Oleic acid (1.8% w/w)
(Aldrich Chemical Company, Inc., Milwaukee, Wis.) and 0.75% (w/w)
morpholine (Sigma) were added to the hot mixture, followed by the
addition of 15% (w/w) of previously molten (65.degree. C.) beeswax
(New Zealand Beeswax Ltd., Orari, South Canterbury, New Zealand).
When necessary, an anti-foaming agent, such as polydimethylsiloxane
(PDMS; Dow Corning, Belgium), was added to the formulation.
Formulation Properties Evaluation
[0092] pH, .degree.Brix and viscosity of the formulations 2, 3 and
6 were measured using digital pH meter (El-Hama, Israel)/(Hanna
Instruments, Liemena, Padua, Italy), digital refractometer (PR-100,
Atago, Japan) and the Brookfield DV-III rheometer (Brookfield,
Mass., USA), respectively. All parameters were measured at room
temperature of 25.degree. C.
Plate and Fruit Samples Coating
[0093] Square polished aluminum plate (10.times.10 cm) was coated
by rubbing 40 .mu.L of formulation 3 on the surface by hand (using
rubber gloves) as described in Hagenmaier et al., J. Food Sci., 61:
562-565, 1996. The coated plate was left to dry at room
temperature.
[0094] Red bell peppers, obtained from a local market, were washed
in water and dried gently using very soft paper towels (Hogla,
Hadera, Israel). Each fruit was cut and flattened into square
shaped samples (10.times.10 cm). Hydrocolloid-high wax coatings
were applied by rubbing 40 .mu.L of formulation 1 on the fruit
sample surface by hand (using rubber gloves). Coated fruits were
then left to dry at ambient temperature.
Fruit Coating
[0095] Red bell pepper fruit (Capsicum annuum cv. Cannon) (Zeraim,
Gedera, Israel), were coated by manual rubbing with 300 .mu.L of
formulations 1-7 on the fruit sample surface by hand (using rubber
gloves). Coated fruits were then left to dry at ambient
temperature.
Plate and Fruit Samples Brushing
[0096] Following coating with formulation 3, each fruit sample was
brushed individually by a custom made vertical brushing apparatus
(FIG. 1A). Samples were brushed using three different types of
brushes composed of horse hair, polyethylene or soft nylon fibers.
Physical properties such as length and thickness of the brushes
were measured using a digital caliper (Mitutoyo, Tokyo, Japan).
Five different rotation speeds and three different brushing time
periods were studied. The brushing procedure is summarized in Table
2 and the physical properties of the brushes are summarized in
Table 3.
TABLE-US-00002 TABLE 2 Brushing protocol. Brushing procedure for
aluminum plate and pepper fruit samples, with different brush types
(horse hair, nylon, polyethylene), brushing time intervals
(minutes) and rotating speed (round per minute). Brush
Horse/Nylon/Polyethylene type Speed (rpm) Time 300 250 200 150 100
(min) Aluminum Aluminum Aluminum Aluminum Aluminum 1 plate and
plate plate and plate plate and pepper fruit pepper fruit pepper
fruit Aluminum Aluminum Aluminum Aluminum Aluminum 5 plate and
plate plate and plate plate and pepper fruit pepper fruit pepper
fruit Pepper fruit Pepper fruit Pepper fruit 10
TABLE-US-00003 TABLE 3 Physical properties of the three brush
types. Thickness (mm)* Length (cm) Brush type 0.176 .+-. 0.03 5
Horse hair 0.284 .+-. 0.02 5 Polyethylene 0.174 .+-. 0.01 5 Nylon
*Each result is the average of 3 determinations .+-. standard
deviation.
Fruit Brushing
[0097] Following coating with formulations 1, 2, and 6 each pepper
fruit was brushed individually by a custom made horizontal brushing
apparatus (FIG. 1B). Fruits were brushed for 3 min at 100 rpm using
two cylindrical horsehair brushes. Following coating with
formulation 3 each pepper fruit was brushed individually by a
custom made horizontal brushing apparatus (FIG. 1B for 5 min at 300
rpm using two cylindrical horsehair brushes.
Scanning Electron Microscopy (SEM)
[0098] SEM micrographs of the three types of brush fiber samples
(polyethylene, soft nylon and horse hair) were obtained using a
JEOL JSM-5410 LV SEM (Tokyo, Japan). Samples of the three types of
brush fibers used in this study (horse, polyethylene and soft
nylon) were gold coated (coating thickness of about 2A) by Polaron
E5150 sputter coater (Hertfordshire, UK) following observation and
photographing by JEOL JSM-5410 SEM (Tokyo, Japan).
Thickness Measurements
[0099] The thickness of the aluminum plate was measured for each
treatment (uncoated, coated with formulation 3 and coated (with
formulation 1) & brushed), using a coating thickness gauge,
(Elcometer 355, Manchester, UK). Three measurements were obtained
at different randomly selected places on the plate surface. Results
are provided as mean.+-.standard deviation (SD).
Weight Loss as a Function of the Wax Weight Percent in Formulation
(Test Group A)
[0100] Test group A containing fifteen (15) red bell pepper fruit
(Capsicum annuum cv. Cannon) (Zeraim, Gedera, Israel) was used to
compare weight-loss rates as a function of the wax weight percent
in formulations. Since weight loss is influenced by fruit size and
surface area (Diaz-Perez et al., J. Sci. Food and Agri., 87, 68-73,
2007), the peppers chosen for this study were of about the same
size with an average weight of 195.+-.22 g. The peppers were
divided into seven treatment groups as follows: (1) uncoated
control, (2) coated with formulation 1 (10% (w/w) carnauba
formulation), (3) coated with formulation 2 (15% (w/w) carnauba
formulation), (4) coated with formulation 4 (5% (w/w) beeswax
formulation), (5) coated with formulation 5 (10% (w/w) beeswax
formulation), (6) coated with formulation 6 (15% (w/w) beeswax
formulation), and (7) coated with formulation 7 (20% (w/w) beeswax
formulation). Each fruit was weighed (.+-.0.01 g) every 24 hours
for 7 days using a STANDARD Series 165 BJ1000C balance (Precisa
Gravimetrics AG, Dietikon, Switzerland). The scale was attached to
a computer and data were collected using BALINT V5.00 software
(Balance interface for Windows, Precisa Instruments AG, Dietikon,
Switzerland). Results are presented as average
(W.sub.0-W.sub.t).times.100/W.sub.0, where W.sub.0 is the weight at
time zero (i.e. initial weight) and W.sub.t is the pepper's weight
after elapsed time t. All peppers were stored at 21.degree. C. and
50% RH. The vapor pressure deficit (VPD), which is the difference
between the amount of moisture in the air and the amount of
moisture the air can hold when it is saturated, was 1.24 kPa.
Pictures of the peppers were taken during storage using a digital
camera (Nikon Coolpix 600, Tokyo, Japan).
Weight Loss as a Function of the Wax Type and Brushing (Test Group
B)
[0101] Test group B containing seventy five (75) red bell pepper
fruit (Capsicum annuum cv. Cannon) (Zeraim, Gedera, Israel) was
used to evaluate the effect of the wax type and brushing on the
weight-loss rate. The peppers chosen for this study were of about
the same size with an average weight of 262.+-.17 g. The peppers
were divided into five treatment groups as follows: (1) uncoated
control, (2) coated with formulation 6 (15% (w/w) beeswax
formulation), (3) coated with formulation 6 followed by brushing,
(4) coated with formulation 2 (15% (w/w) carnauba wax formulation),
and (5) coated with formulation 2 followed by brushing. Each fruit
was weighed (.+-.0.01 g) every 24 hours for 7 days using a STANDARD
Series 165 BJ1000C balance (Precisa Gravimetrics AG, Dietikon,
Switzerland). The scale was attached to a computer and data were
collected using BALINT V5.00 software (Balance interface for
Windows, Precisa Instruments AG, Dietikon, Switzerland). Results
are presented as average (W.sub.0-W.sub.t).times.100/W.sub.0, where
W.sub.0 is the weight at time zero (i.e. initial weight) and
W.sub.t is the pepper's weight after elapsed time t. All peppers
were stored at 21.degree. C. and 50% RH. The vapor pressure deficit
(VPD), which is the difference between the amount of moisture in
the air and the amount of moisture the air can hold when it is
saturated, was 1.24 kPa. Pictures of the peppers were taken during
storage using a digital camera (Nikon Coolpix 600, Tokyo,
Japan).
Gloss Measurements (Test Group C)
[0102] Gloss of pepper fruit samples and aluminum plates that were
coated with formulation 3 were examined using a flat surface
hazemeter, capable of measuring gloss at coincident angles of
20.degree. and 60.degree. (Novo-Haze, Rhopoint Instrumentation
Ltd., Germany). The results were recorded in gloss units (GU). A
highly polished plane surface of black glass served as a standard
having arbitrarily assigned gloss value of 100 at different
coincident angles. Gloss measurements were performed on the same
sample when uncoated, coated and coated & brushed. Each
measurement contained three readings taken at different randomly
selected points on the sample surface. All measurements were
performed at room temperature. Results are provided as the
arithmetic mean.+-.SD. Pepper fruit surface samples from each
treatment with formulation 3 (uncoated, coated and coated &
brushed) were photographed using a research Grade Leica DMLM
microscope.
Gloss Measurements (Test Group D)
[0103] Test group D containing forty eight (48) red bell pepper
fruit (Capsicum annuum cv. Cannon) (Zeraim, Gedera, Israel) was
used for the gloss measurements. The peppers were divided into
three treatment groups as follows: (1) uncoated control, (2) coated
with formulation 6 (15% (w/w) beeswax formulation), and (3) coated
with formulation 6 followed by brushing. Average gloss for each
treatment was measured by two types of glossmeters.
[0104] The first glossmeter was a flat-surface glossmeter (407
Statistical Glossmeter; Elcometer, Rochester Hills, Mich.) capable
of measuring gloss at three angles: 20.degree., 60.degree. and
85.degree.. Eight peppers from each treatment were cut into flat
square samples (5.times.10 cm) using a sharp surgical blade
(Bar-Naor Ltd., Ramat Gan, Israel). Results were recorded in gloss
units (GU), which are relative to a highly polished plane surface
of black glass with a gloss value of 88.9, 93.5 and 99.7 GU at
20.degree., 60.degree. and 85.degree., respectively, which served
as the standard.
[0105] The second glossmeter was a curved-surface glossmeter (U.S.
Pat. No. 6,018,396) which illuminates the pepper with a light beam
from a helium-neon laser at an incident angle of 60.degree.. A
semi-conductive plate collects all of the reflected light from the
surface of the peppers. A video recorder (Sony Handycam video Hi8,
Tokyo, Japan), positioned directly facing the plate, was used to
record the images. The recorded images were relayed to a computer
where they were analyzed by a special computer program which
translated them into a goniophotometric curve of light intensity
(arbitrary units) vs. distance or light scattering (pixels). The
widths of the curves at half-maximum (50% intensity) were measured
as an indicator of gloss (Nussinovitch et al., J. Food Sci., 61,
383-387, 1996). This apparatus permits measurements of whole
fruits, i.e. it is a non-destructive procedure. The measured object
can be placed inside the measuring apparatus without cutting it or,
when needed, cut samples can be used. Twelve (12) whole (non-cut)
peppers from each treatment were measured (n=36). Results were
recorded in average curve widths at 50% intensity.
Gloss Evaluation (Test Group E)
[0106] Test group E contained nine (9) peppers, which were divided
into three treatment groups (n=3) as follows: (1) uncoated control,
(2) coated with formulation 3 (18% (w/w) carnauba formulation), and
(3) coated with formulation 3 followed by brushing. Each member of
the evaluation panel received all nine peppers and was asked to
rank them by their glossy appearance (1--the least glossy
appearance, 9--the glossiest appearance).
Roughness (Test Group D)
[0107] The roughness measurements were performed on surface samples
(5.times.10 cm) cut with a sharp surgical blade from four peppers
from each treatment group in test group D, ((1) uncoated control,
(2) coated with formulation 6 (15% (w/w) beeswax formulation), and
(3) coated with formulation 6 followed by brushing) every 48 hours
for 7 successive days using a portable surface-roughness tester
(Surftest-301, Mitutoyo Corp., Tokyo, Japan). Each measurement
tested a 7.5-mm path. Results were recorded as R.sub.a and R.sub.z
where R.sub.a is the arithmetic average of the absolute values of
the distance between the arithmetical mean line and the roughness
profile (y) within the sampling length (lm) calculated using
equation (1); and R.sub.z is the arithmetic average of the single
peak-to-valley heights (Z) of five adjacent sampling lengths
calculated using equation (2). Both R.sub.a and R.sub.z are
provided in micrometers. Every measurement consisted of three
readings taken along randomly chosen paths on the sample surface.
All measurements were performed at room temperature. Results are
provided as arithmetic mean.+-.standard deviation (SD).
Ra = 1 lm .intg. 0 lm f ( y ) dx ( 1 ) Rz = Z 1 + Z 2 + Z 3 + Z 4 +
Z 5 5 ( 2 ) ##EQU00001##
Color (Test Group F)
[0108] Test group F containing ten (10) red bell pepper fruit
(Capsicum annuum cv. Cannon) (Zeraim, Gedera, Israel) was used for
color evaluation. The peppers were divided into five treatment
groups as follows (n=2): (1) uncoated control, (2) coated with
formulation 6 (15% (w/w) beeswax formulation), (3) coated with
formulation 6 followed by brushing, (4) coated with formulation 2
(15% (w/w) carnauba wax formulation), and (5) coated with
formulation 2 followed by brushing. The colors of peppers from each
treatment group were measured every 24 hours for 7 successive days
using Minolta Color Meter CR200 (Osaka, Japan). Prior to the
measurement, the instrument was calibrated with a white (standard
surface) plate. Surface pigmentation variations for each pepper
were compensated for by recording the average of three readings
taken at random positions on the pepper's surface. Color changes
were assessed by three parameters: L* represents the lightness of
the sample and ranges from black (L*=0) to white (L*=100), a*
represents the red-green axis and ranges from -60 for green to +60
for red, and b* represents the yellow-blue axis and ranges from -60
for blue to +60 for yellow (Hutchings, Food color and Appearance,
Gaithersburg, Md.: Aspen Publishers, 2.sup.nd Ed., 227-265, 1999).
Results were recorded as average L*, a*, b* values.+-.SD.
Mechanical Properties (Test Group D)
[0109] The firmness of four bell peppers from each treatment group
in test group D ((1) uncoated control, (2) coated with formulation
6 (15% (w/w) beeswax formulation), and (3) coated with formulation
6 followed by brushing), was measured every 48 hours for 7 days by
performing puncture tests using an Instron Universal Testing
Machine (UTM) Model 5544 (Instron Engineering Corp., Canton, Mass.)
equipped with a 50 N load cell. Each fruit was punctured using a
3-mm diameter punch at a deformation rate of 10 mm min.sup.-1. The
UTM was connected to an IBM-compatible personal computer with a
card. Using "Merlin" software (Instron), data acquisition and
conversion of the Instron's continuous voltage vs. time output into
digitized force vs. deformation relationships was performed.
Results are provided as the arithmetic mean.+-.SD.
Microscopy (Test Group D)
[0110] Pepper fruit surface samples (1.times.1 cm) cut with a sharp
surgical blade from each treatment group in test group D, ((1)
uncoated control, (2) coated with formulation 6 (15% (w/w) beeswax
formulation), and (3) coated with formulation 6 followed by
brushing), were photographed (20.times. magnification) on the first
day of storage using the digital camera accessory of the light
microscope (Leica DMLM, Wetzlar, Hesse, Germany).
Simulations of Storage and Marketing Conditions (Test Groups C and
H)
[0111] Test groups G and H each containing ninety six (96) red bell
pepper fruit (Capsicum annuum cv. Cannon) (Zeraim, Gedera, Israel)
were used for simulation of storage and marketing conditions. In
each test group the peppers were divided into three treatment
groups (n=32) as follows: (1) uncoated control, (2) coated with
formulation 6 (15% (w/w) beeswax formulation), and (3) coated with
formulation 6 followed by brushing. Group G was stored at 7.degree.
C. and 95% RH (VPD=0.05 kPa) for 3 weeks and group H was stored for
5 weeks under the same temperature and RH conditions. After their
respective storage periods, the peppers were transferred to
20.degree. C. and 75% RH (VPD=0.58 kPa) for 3 days, simulating
supermarket conditions (Goren et al., Adv. Horticultural Sci., 25,
26-31, 2011). Each fruit was weighed before and after cool storage
and once again after the 3 days of storage at room temperature.
Weight loss was recorded and analyzed as described hereinabove.
Sensory Evaluation
[0112] Five sensory evaluation tests were performed on uncoated and
treated (formulations 2 & 6) red bell peppers.
[0113] 1. Initial Taste Evaluation
[0114] Taste of the pepper fruits was evaluated by a panel of 18
members on the first day of the study. The aim of this first taste
evaluation test was to study whether the 15% (w/w) beeswax coating
formulation (formulation 6) changes the flavor of the fruit. Thus,
a blind triangle test was performed, in which each panel member
received three fruit samples: two uncoated and one coated fruit, or
two coated and one uncoated fruit. The panel member had to
distinguish the dissimilar sample based only on taste.
[0115] 2. Gloss Evaluation
[0116] The aim of the gloss evaluation was to determine whether the
coated commodities will differ from the uncoated ones in the eyes
of the consumer. Each panel member received six peppers, two from
each from each treatment group in test group D, ((1) uncoated
control, (2) coated with formulation 6 (15% (w/w) beeswax
formulation), and (3) coated with formulation 6 followed by
brushing), and was asked to rank the fruits according to their
gloss, with 1 denoting the least glossy appearance and 6 denoting
the glossiest pepper appearance (Marcilla et al., Spanish J. Agri.
Res., 7, 181-189, 2009).
[0117] 3. Taste Evaluation after Storage
[0118] After 1 week in storage at 21.degree. C. and 50% RH,
additional sensory evaluation test was performed by a 13-member
panel. Another taste test was performed to determine whether
coating the fruit with beeswax had created off-flavors as a result
of changes in the normal respiration process during storage. A
triangle test was performed as described hereinabove and in
addition, the testers were asked to describe the taste that
distinguished the chosen sample from the other two.
[0119] 4. Sensory Firmness Evaluation after Storage
[0120] In addition, a firmness evaluation test was performed after
1 week in storage at 21.degree. C. and 50% RH. The panel members
were asked to rank six peppers according to their hardness, with 1
being the softest and 6 being the firmest.
[0121] 5. Final Sensory Evaluation
[0122] A final sensory evaluation test was designed to analyze
consumer preferences considering all quality parameters together.
This test consisted of 10 peppers, two from each treatment group in
test group B ((1) uncoated control, (2) coated with formulation 6
(15% (w/w) beeswax formulation), (3) coated with formulation 6
followed by brushing, (4) coated with formulation 2 (15% (w/w)
carnauba wax formulation), and (5) coated with formulation 2
followed by brushing.) Each panel member was asked to choose the
three peppers that he/she would buy at the supermarket.
Statistical Analysis
[0123] Statistical analyses were conducted with JMP software (SAS
Institute, 2007, Cary, N.C.), including three-way ANOVA t-tests and
Tukey-Kramer Honestly Significant Difference (HSD) test for
comparisons of means, with p.ltoreq.0.05 being considered
significant.
Example 2: Properties of Formulations 2, 3 and 6
[0124] The properties of formulations 2, 3 and 6 were evaluated.
The measured pH, .degree. Brix and viscosity are presented in table
4.
TABLE-US-00004 TABLE 4 Physical properties of the hydrocolloid-high
wax formulations Viscosity at 70 1/sec Formulation pH .degree. Brix
shear rate (cP) 2 9.09 28.1 195 3 8.90 15.0 220 6 8.88 19.1 85
Example 3: Thickness of Coating (Formulation 3)
[0125] The thickness of the uncoated aluminum plate used in this
study was 999.+-.17 micron. After the plate was coated, a thickness
of 1032.+-.22 micron was measured and after brushing the coated
plate, its thickness was 1015.+-.19 micron. It is therefore
contemplated that the wax-hydrocolloid coating thickness on a metal
is approximately 30 micron, and that brushing the coated material
decreases the coating thickness by half. Because a metal plate
responds differently to the coating formulation as compared to the
fruit, it is not conclusive that the thickness of the coating on a
metal plate resembles the thickness of the fruit coating.
Furthermore, the measurements which were performed on the plate
could not be performed on a fruit sample for the following reasons:
there is a large diversity between thicknesses of different
peppers, different sizes of peppers have different surface areas on
which the coating is spread, and postharvest fruit continues to
carry out metabolic processes such as respiration, enzymatic
activity etc. (MacRae et al., Planta, 188, 314-323, 1992). As a
result, the thickness of the fruit sample changes with time and
cannot be used for coating thickness measurements. However, from
micrographs taken from surface area of uncoated, coated and coated
& brushed pepper samples (FIGS. 2A-2C), it is evident that the
thickness of the coating on pepper fruit diminishes when applying
the brushing procedure. In FIG. 2A the surface cells silhouette can
clearly be seen, where in FIG. 2B the cells' surface is covered by
the coating. After the sample brushing, the thickness of the
coating decreased as is evident by the silhouette of the surface
cells which is visible once again together with the coating lair
(FIG. 2C).
Example 4: Weight Loss--Effect of the Wax Weight Percentage (Test
Group A)
[0126] The slopes and coefficient of determination (R.sup.2) of
weight loss as a function of storage time in peppers from treatment
group (1) uncoated and coated by formulations comprising carnauba
wax from the following treatment groups: (1) uncoated, coated with
(2) formulation 1 (10% (w/w) carnauba formulation), and (3) coated
with formulation 2 (15% (w/w) carnauba formulation), are summarized
in table 5.
TABLE-US-00005 TABLE 5 Weigh loss rate of peppers coated by
formulations comprising carnauba wax with different weight
percentages (10 and 15% (w/w)). % Weight Car- loss rate Treatment
Formu- nauba per hour Statistical group lation wax (%) (SE)
10.sup.-3 (R.sup.2) significance 1 -- -- 0.11 4.14 0.99 a 2 1 10
0.10 5.11 0.99 b 3 2 15 0.08 4.01 0.99 a
[0127] The slopes indicate the weight-loss rate in each treatment.
The fruit coated with formulation 2, having the highest wax content
(15% (w/w)) among the carnauba wax formulations tested for the
weight loss, had a significantly smaller slope (lower weight-loss
rate) than the other two groups (p.ltoreq.0.05). Its weight loss
rate was 25% lower than that of the uncoated fruit, wherein the
weight loss of formulation 2 (10% carnauba wax) was only 12% lower
than that of the uncoated fruit. Therefore, it may be concluded
that raising the wax content in the formulation above 10% (w/w)
afforded significantly decreasing the weight loss of the coated
fruit peppers.
[0128] The slopes and coefficient of determination (R.sup.2) of
weight loss as a function of storage time in peppers from treatment
group (1) uncoated and coated by formulations comprising beeswax
from the following treatment groups: (4) coated with formulation 4
(5% (w/w) beeswax formulation), (5) coated with formulation 5 (10%
(w/w) beeswax formulation), (6) coated with formulation 6 (15%
(w/w) beeswax formulation), and (7) coated with formulation 7 (20%
(w/w) beeswax formulation), are summarized in table 6.
TABLE-US-00006 TABLE 6 Weigh loss rate of peppers coated by
formulations comprising beeswax with different weight percentages
(5, 10, 15 and 20% (w/w)). Weight loss rate Treatment Formu- % per
hour (SE) Statistical group lation Beeswax (%) 10.sup.-3 (R.sup.2)
significance 1 -- -- 0.052 1.41 1.00 a 4 4 5 0.033 1.33 0.99 bc 5 5
10 0.033 1.42 0.99 bc 6 6 15 0.028 1.19 0.99 c 7 7 20 0.027 1.31
0.99 c
[0129] The fruits coated with formulations 4 and 5, comprising 5%
(w/w) and 10% (w/w) beeswax respectively demonstrated a decrease of
the storage weigh loss of 37% compared to the uncoated fruit.
Formulations 6 and 7, comprising higher beeswax content allowed
reduction of 46% and 48% respectively in the weight loss of pepper
fruits, compared to the uncoated fruits (p<0.05). Therefore,
raising the wax content in formulations comprising beeswax
decreased the weight loss of the coated peppers, wherein the
formulations comprising wax concentration above 10% (w/w) allowed
diminishing the weight loss by almost 50%.
Example 5: Weight Loss--Effect of the Wax Type and Brushing (Test
Group B)
[0130] The retained weight (%) of the pepper fruits from test group
B (formulations 2 & 6) during 7 days of storage is presented in
FIG. 3. Maalekuu et al. (J. Am. Soc. Horticultural Sci., 130,
735-741, 2005) established the linear relationship between the
percentage of weight loss in peppers and elapsed time. Similar
relations were found here. The slopes and coefficient of
determination (R.sup.2) of weight loss as a function of storage
time in peppers from treatment group (1) uncoated and coated by
formulations comprising 15% (w/w) carnauba wax or 15% (w/w) beeswax
from the following treatment groups: (1) uncoated control, (2)
coated with formulation 6 (15% (w/w) beeswax formulation), (3)
coated with formulation 6 followed by brushing, (4) coated with
formulation 2 (15% (w/w) carnauba wax formulation), and (5) coated
with formulation 2 followed by brushing are summarized in table
7.
TABLE-US-00007 TABLE 7 Weigh loss rate of peppers coated by
formulations comprising 15% (w) carnauba wax or 15% (w/w) beeswax,
with and without brushing. Weight loss rate Treatment Brush- per
hour (SE) Statistical group Formulation ing (%) 10.sup.-3 (R.sup.2)
significance 1 -- - 0.068 0.79 1.00 a 2 6 (carnauba) - 0.040 0.87
1.00 d 3 6 (carnauba) + 0.045 0.74 1.00 c 4 2 (beeswax) - 0.057
0.79 1.00 b 5 2 (beeswax) + 0.054 0.73 1.00 b
[0131] The slopes indicate the weight-loss rate in each treatment.
The uncoated fruit had a significantly greater slope (higher
weight-loss rate) than any other treatment, i.e. than any of the
coated fruit (p.ltoreq.0.0001). This demonstrates that coatings
with either beeswax or carnauba wax, regardless of whether they are
followed by brushing, reduce the weight-loss rate and contribute to
shelf-life extension of peppers. The beeswax formulation resulted
in the lowest weight loss, differing significantly from both
carnauba wax treatments (p.ltoreq.0.0001). Moreover, the
beeswax-coated and brushed fruit showed a higher rate of weight
loss than the beeswax-coated fruit without brushing
(p.ltoreq.0.05). This suggests that the brushing technique
decreases the integrity of the coating, albeit only minimally
because the beeswax-coated and brushed peppers still demonstrated a
significantly lower weight-loss rate than controls. After 7 days in
storage, the uncoated fruit lost almost twice the weight as
compared to the weight lost by the beeswax-coated fruit. Moreover,
the uncoated peppers lost over 5% of their initial weight after 72
hours, i.e. after 3 days at room temperature, whereas the peppers
coated with the beeswax formulation only lost this amount after 144
hours (6 days). Thus, the beeswax coating inhibited pepper
shriveling, retained its quality and doubled its shelf life. It is
therefore concluded that the beeswax formulation was by far the
most suitable formulation for shelf-life extension of red bell
peppers.
Example 6: Weight Loss--Visual Appearance (Test Group B,
Formulation 6)
[0132] Differences in the appearance of the red bell peppers test
group B (treatment groups: (1) uncoated control, (2) coated with
formulation 6 (15% (w/w) beeswax formulation), and (3) coated with
formulation 6 followed by brushing,)) during storage at room
temperature are presented in FIG. 4. Senescence of the uncoated
fruit clearly occurred much faster than in the treated fruit. After
1 week at room temperature (panel B), the uncoated peppers started
to shrivel while the coated peppers maintained their "fresh"
appearance. These differences in appearance were manifested during
storage. After 2 weeks (panel C), the coated and brushed peppers
also started to shrivel whereas the coated fruit retained a smooth
surface. These results are consistent with the weight-loss rates
shown in FIG. 3. The micrographs in FIGS. 5A-5C show the
differences between the surface appearance of the peppers in each
treatment (1, 2 & 3). In FIG. 5A, the pepper's cells can be
easily observed, whereas in FIG. 5B the surface is covered by the
coating and therefore the cells are less distinguishable, if at
all. In FIG. 5C, slits are observed on the pepper's surface,
supporting the assumption that brushing damages the coating's
integrity.
Example 7: Gloss of Aluminum Plate (Formulation 3)
[0133] Aluminum is a very shiny chemical element. The gloss of the
uncoated aluminum plate used in this study was 250.+-.20 gloss
units. After coating, the gloss of the plate extremely decreased to
an average of 60.+-.10 gloss units which is nearly 20% its gloss
before coating. The brushing process in all brush types (horse
hair, polyethylene and soft nylon) at brushing time intervals of 1
and 5 minutes, and all five brushing speeds (100, 150, 200, 250 and
300 rpm) increased the gloss of the plate but resulted in very
minor and non-significant effect (FIGS. 6A-6B).
Example 8: Gloss of Pepper Fruit Samples (Test Group C)
[0134] Table 8 summarizes the average gloss of uncoated, coated and
coated & brushed peppers. After hand coating of the pepper
samples with formulation 3, comprising 18% carnauba wax, the gloss
of the red bell pepper significantly diminishes. The average gloss
of the untreated pepper samples was 13.2.+-.1.5 gloss units in
comparison to 3.7.+-.0.95 gloss units after coating treatment.
Namely, the coating diminishes the gloss of the coated commodity by
a factor of .about.3.6 (Down to .about.30% of the initial gloss).
Red bell pepper is known for its natural gloss which is attributed
to sterol and wax natural coating composition (Nussinovitch et al.,
Lebensm.-Wiss. u.-Technol, 29:184-186, 1995). Surprisingly, where
the time interval for brushing increased from 1 to 5 or 10 minutes,
another phenomenon was observed as follows: at 1 minute, using
horse hair brushes at 100 rpm, the recorded gloss values were
7.8.+-.1.4, whereas after 5 or 10 minutes of brushing the recorded
gloss values increased to 8.4.+-.1.0 and 9.5.+-.2.0, respectively.
Thus, an increase in the time interval of polishing at the same
speed and brush type resulted in an increase of the gloss values.
It is noteworthy that at this brush type and brushing speed, no
significant differences were observed when increasing the time
intervals from 5 to 10 minutes. The highest gloss value measured
(i.e. 9.5), although being lower in comparison to the value of
uncoated pepper (i.e. 13.2), still represents a glossy surface that
could be easily sold as the natural uncoated commodity. The highest
contribution of the brushing procedure was observed at 300 rpm. At
this brushing speed using the horse hair brush, increasing the
brushing time interval to 10 minutes resulted in an observed gloss
of 10.3.+-.2.0 gloss values which represents an increased from
.about.30% back to .about.80% of the initial gloss of the uncoated
pepper.
[0135] When increasing the speed from 100 to either 200 or 300 rpm
using polyethylene brushes at brushing time intervals of 1 to 10
minutes, a general increase in the gloss values was measured. The
longer the brushing time intervals, the higher the gloss values
that were measured. However, only brushing for 10 minutes resulted
in a sensory accepted value of 8.4.+-.1.7 gloss units. When
increasing the speed from 100 to either 200 or 300 rpm using nylon
brushes at brushing time intervals of 1 to 10 minutes, the gloss
values have not changed significantly or showed a significant
increase (Table 8).
TABLE-US-00008 TABLE 8 Average gloss of uncoated, coated and coated
& brushed (after brushing red pepper samples at three brushing
speeds (100, 200 and 300 rpm), three brushing time intervals (1, 5
and 10 min) and using three brush types (horse hair, polyethylene
and soft nylon)) Average gloss of Average gloss coated Average of
coated peppers gloss of peppers after before uncoated brushing
Brushing Brushing brushing peppers (GU)* Brush type time (min)
speed (rpm) (GU)* (GU)* 10.32 .+-. 2.04a .sup. Horse 10 300 3.83
.+-. 0.32 12.72 .+-. 0.82 9.54 .+-. 2.03ab Horse 10 100 3.33 .+-.
0.12 12.74 .+-. 0.75 9.16 .+-. 0.59ab Horse 5 300 4.33 .+-. 0.29
11.49 .+-. 1.15 8.73 .+-. 2.52abc Nylon 5 300 4.17 .+-. 0.50 12.88
.+-. 0.48 8.39 .+-. 1.67abc Polyethylene 10 300 3.20 .+-. 0.10
13.74 .+-. 1.56 8.37 .+-. 1.05abc Horse 5 100 2.67 .+-. 0.06 10.42
.+-. 1.19 8.37 .+-. 3.02abc Nylon 5 100 3.60 .+-. 0.46 14.04 .+-.
1.48 8.29 .+-. 0.49abcd Horse 5 200 4.17 .+-. 0.15 12.94 .+-. 1.58
7.76 .+-. 1.42abcd Horse 1 100 2.87 .+-. 0.15 10.99 .+-. 1.54 7.67
.+-. 1.47abcd Nylon 5 200 2.73 .+-. 0.15 12.89 .+-. 0.76 7.47 .+-.
1.82abcd Polyethylene 1 200 2.93 .+-. 0.06 13.07 .+-. 1.24 7.33
.+-. 1.61abcd Horse 1 200 2.57 .+-. 0.06 7.33 .+-. 1.61 7.29 .+-.
0.57abcd Nylon 10 300 3.07 .+-. 0.15 14.60 .+-. 1.11 7.23 .+-.
1.21abcd Horse 10 200 4.67 .+-. 0.25 12.81 .+-. 1.41 6.81 .+-.
2.37abcd Polyethylene 1 300 3.07 .+-. 0.25 13.59 .+-. 0.88 6.49
.+-. 2.01abcd Polyethylene 5 300 2.47 .+-. 0.06 13.42 .+-. 0.94
6.41 .+-. 0.56abcd Nylon 1 300 2.50 .+-. 0.00 15.16 .+-. 2.17 6.16
.+-. 0.76abcd Nylon 10 200 2.57 .+-. 0.06 12.89 .+-. 1.04 6.13 .+-.
0.50abcd Polyethylene 1 100 2.33 .+-. 0.12 12.21 .+-. 1.04 6.06
.+-. 1.84abcd Polyethylene 10 200 2.43 .+-. 0.21 12.71 .+-. 0.66
6.03 .+-. 0.34abcd Horse 1 300 2.93 .+-. 0.42 13.59 .+-. 1.51 5.89
.+-. 0.78abcd Nylon 1 200 2.57 .+-. 0.15 13.66 .+-. 0.81 5.49 .+-.
0.50abcd Nylon 1 100 2.53 .+-. 0.06 13.96 .+-. 0.98 5.18 .+-.
1.11bcd Nylon 10 100 2.87 .+-. 0.12 13.84 .+-. 0.97 4.26 .+-.
0.50bcd Polyethylene 5 200 3.23 .+-. 0.25 13.09 .+-. 0.74 3.97 .+-.
0.51cd Polyethylene 10 100 2.97 .+-. 0.15 12.50 .+-. 0.29 3.38 .+-.
0.54d .sup. Polyethylene 5 100 4.83 .+-. 0.12 14.27 .+-. 1.58 *Each
result is the average of 9 determinations .+-. SD. Difference are
significant at p .ltoreq. 0.05.
[0136] Upon general comparison between different brush types at
different brushing speed and brushing time intervals it is evident
that the horse brush is the most efficient type of brush with nylon
and polyethylene brushes being less efficient in restoring gloss to
the peppers. Without being bound by any theory or mechanism of
action, it is contemplated that the porosity of the horse hair
brush as evident from its cross-section scanning electron
micrograph, enables to absorb the fluidity smeared wax-hydrocolloid
formulation resulting in a better application of the coating on the
pepper surface. Both the synthetic nylon and polyethylene brushes,
contain fibers that are not porous. Accordingly, these brushes are
not capable of absorbing any coating fluid/preparation and merely
afford its smearing on the surface (FIGS. 7A-7D).
[0137] Upon brushing of the coated commodity an increase in the
gloss of the coated fruit in comparison with the coated non-glossy
surface (3.7 gloss units in average) was obtained. This increase
was not sufficient to restore the natural gloss values of the
pepper skin. At same brushing time interval (1 minute) and using
the same brush type (horse hair), the following values of gloss
units were obtained: 7.7.+-.1.4 at brushing speed of 100 rpm,
7.3.+-.1.6 at brushing speed of 200 rpm and 6.0.+-.0.3 at brushing
speed of 300 rpm. These values of are 1.6 to 2.1 times larger than
the values of coated non-glossy pepper (Table 8).
[0138] The results presented in FIG. 8 show that each treatment
provides a significant difference in gloss values. The uncoated
peppers showed the highest gloss values as compared to the other
treated peppers. The peppers coated with the formulation comprising
carnauba wax were the least glossy, and the peppers coated with the
formulation comprising carnauba wax that underwent brushing
treatment showed nearly doubled gloss valued as compared to the
coated peppers that were not subjected to brushing treatment. It is
thus concluded that post-coating brushing treatment provides a
significantly high increase in the fruit's gloss. Hence, by using
the brushing procedure, peppers with improved properties and fewer
damages to their appearance may be obtained.
Example 9: Gloss of Pepper Fruits (Test Group D)
[0139] The gloss of pepper fruits coated with formulation 6
comprising 15% beeswax and of the coated peppers which underwent
following brushing was measured. The results of the surface
glossmeter measurements are presented in FIG. 9. Measurements taken
at both 60.degree. and 85.degree. angles demonstrated that the
natural gloss of the pepper decreases after coating with the
beeswax formulation and increases after brushing to a level which
is not significantly different from the natural gloss of the
uncoated pepper (p.ltoreq.0.01). The gloss measurements using the
curved-surface glossmeter showed similar results. The highest value
at full width at half height was detected for the coated fruit
(28.2.+-.1.0), which was significantly different (p.ltoreq.0.0001)
from the value of the coated and brushed peppers (23.9.+-.1.1). It
is contemplated that the width at half height of the
goniophotometric curve indicates the inverse of the gloss level,
i.e., the larger the width at half height, the lower the measured
gloss value. The increase in gloss as a result of brushing was in
agreement with the enhanced gloss of polished peppers as compared
to unpolished ones due to the regenerated structure of the
epicuticular wax layer (Charles et al., Postharvest Bio. Technol.,
47, 21-26, 2008). Thus, even though the highest gloss values were
achieved for uncoated fruits, coating with 15% (w/w) formulation
decreased the peppers' gloss by .about.25% while brushing increased
it again by .about.15% resulting in a mere 10% reduction in its
natural gloss.
Example 10: Roughness (Test Group D)
[0140] As a result of the high rate of weight loss of the uncoated
fruit during storage (FIG. 3), its surface roughness increased
rapidly with time in comparison to the two other coated groups
(treatment groups (2) coated with formulation 6 (15% (w/w) beeswax
formulation) and (3) coated with formulation 6 followed by
brushing)) (FIG. 10). After 7 days of storage, the average R.sub.a
and R.sub.z values of the uncoated peppers were 5.8.+-.1.5 and
19.4.+-.7.3 .mu.m, respectively, significantly higher than the
R.sub.a and R.sub.z values of the coated peppers (2.9.+-.0.9 and
12.3.+-.2.7 .mu.m, respectively) and coated and brushed peppers
(2.8.+-.0.8 and 11.8.+-.2.1 .mu.m, respectively) (p.ltoreq.0.05).
FIGS. 11A and 11B show the surface-roughness profiles of the red
bell peppers from the three treatments, namely uncoated, coated,
and coated and brushed, after 1 and 7 days of storage,
respectively. On the first day of storage, all three roughness
profiles were similar. However, after 7 days, the uncoated profile
(and surface of the pepper) was rougher than the profiles of
treated peppers. These results also indicate that the
beeswax-coating formulation slowed the peppers' senescence process
and thus extended their shelf life.
Example 11: Color (Test Group F)
[0141] Red bell peppers change their color during ripening due to a
decrease in the major chloroplast pigment, chlorophyll, concomitant
with a rise in the levels of various carotenoids, resulting in a
deep red color in the fully ripe peppers (Ha et al., J. Exp.
Botany, 58, 3135-3144, 2007). During the first 3 days of storage,
three treatments groups ((1) uncoated control, (2) coated with
formulation 6 (15% (w/w) beeswax formulation), and (3) coated with
formulation 6 followed by brushing,) showed an increase in a* and
b* values: for the uncoated fruit, from 21.6.+-.1.8 to 28.1.+-.2.0
and from 10.5.+-.1.5 to 14.1.+-.1.6, respectively; for the
beeswax-coated pepper from 18.9.+-.2.0 to 28.7.+-.2.3 and from
10.0.+-.2.8 to 16.1.+-.1.2, respectively; for the beeswax-coated
and brushed fruit from 19.4.+-.3.3 to 23.8.+-.1.7 and from
11.8.+-.1.5 to 11.8.+-.1.9, respectively. From day 3, these levels
remained constant (measurements every 24 hours) until day 7 of
storage. L* did not show any changes in any treatment during
storage, and had an average value of 33.2.+-.1.2. These results,
collected during the 7 days of storage, showed no significant
differences in color change among the three treatments
(p.ltoreq.0.0001). Therefore, the beeswax coating formulation did
not affect the color of the pepper from its natural change during
the ripening process.
Example 12: Mechanical Properties (Test Group D)
[0142] The force at puncture was similar for treated and untreated
peppers. Uncoated, coated with beeswax formulation, and coated with
15% (w/w) beeswax formulation and then brushed values that were
obtained are 13.3.+-.1.8 N, 13.6.+-.0.8 N and 13.5.+-.0.8 N,
respectively. These values did not change significantly during 7
days of storage (p.ltoreq.0.0001). However, the deformation at
puncture increased during storage: the uncoated fruit went through
the biggest change, resulting in a significantly higher
(p.ltoreq.0.001) deformation (20.8.+-.2.4 mm) on day 7 of storage,
relative to the coated (13.1.+-.2.7 mm) and coated and brushed
(14.7.+-.2.1) fruit (FIG. 12). These results demonstrate that the
uncoated fruits, after 7 days at 20.degree. C. and 50% RH, were
less rigid than the coated ones. Hence, coated fruits are stiffer
than the uncoated ones and coating is shown to preserve the fruit's
mechanical properties, resulting in extended shelf life.
Example 13: Simulations of Storage and Marketing Conditions (Test
Groups G and H)
[0143] Groups G and H both showed a significantly higher percentage
of weight-loss of untreated vs. 15% (w/w) beeswax formulation
coated fruit after storage at 7.degree. C. and 95% RH
(p.ltoreq.0.0001). After 3 weeks, weight loss of the uncoated fruit
in group G amounted to 3.0.+-.0.4%, compared to 2.4.+-.0.4% and
2.4.+-.0.5% in the coated and coated and brushed fruits,
respectively. In group H, after 5 weeks of storage, the weight loss
of the uncoated fruit amounted to 6.2.+-.1.3%, compared to
3.4.+-.0.5% and 3.5.+-.0.9% for the coated and coated and brushed
peppers, respectively. The percentage of weight-loss, which is
mainly attributed to loss of water, of the coated peppers was far
lower than other experiments showing a water loss of over 10% for
coated peppers after 21 days of cold storage (Ozden et al., Euro.
Food Res. Technol., 214, 320-326, 2002). After additional 3 days at
20.degree. C. and 75% RH, the uncoated, coated, and coated and
brushed fruits from group G lost an additional weight of
1.8.+-.0.3%, 1.3.+-.0.2% and 1.4.+-.0.3%, respectively. For group
H, after 3 days at 20.degree. C. and 75% RH (following 5 weeks at
7.degree. C. and 95% RH), the uncoated, coated, and coated and
brushed peppers lost an additional weight of 1.8.+-.0.4%,
1.0.+-.0.2% and 1.0.+-.0.2% of their respective weights. Thus,
after 5 weeks of cool storage, the uncoated fruit lost 6.2.+-.1.3%
of its initial weight and was already shriveled and soft, while the
coated and coated and brushed fruit lost only 3.4.+-.0.5% and
3.5.+-.0.9% of their initial weights, respectively, and maintained
their "fresh" appearance and firmness.
Example 14: Sensory Evaluation (Formulations 2 and 6)
[0144] In both the initial taste and taste after storage
evaluations, 60% of the panel members could not distinguish between
the coated and uncoated fruit. In the second taste test, the panel
members were also asked to note any specific taste differences
between the samples: no off-flavors were detected for any of the
treated peppers. The gloss evaluation results were in agreement
with the physical measurements, i.e., the panelists determined that
the beeswax and carnauba wax coating decreased the peppers' gloss
while the brushing increased it to a level that was not noticeably
different from the natural gloss. The firmness evaluation showed
that after 7 days of storage, the treated peppers (coated by
formulation 2 and formulation 6) were significantly firmer than the
untreated ones (p 0.0001). In the final sensory test, no uncoated
peppers were chosen; 40% of the chosen peppers were coated and 60%
were coated and brushed. These results demonstrate that consumers
tend to prefer the coated peppers, and in particular the coated and
brushed peppers, over their uncoated counterparts.
[0145] The novel formulations of the present invention contribute
to extending the pepper's shelf life. In addition, a special
brushing procedure can increase the coated fruit's gloss following
its decrease as a result of the coating process.
[0146] The foregoing description of the specific embodiments will
so fully reveal the general nature of the invention that others
can, by applying knowledge within the skill of the art (including
the contents of the references cited herein), readily modify and/or
adapt for various applications such specific embodiments, without
undue experimentation, without departing from the general concept
of the present invention. Therefore, such adaptations and
modifications are intended to be within the meaning and range of
equivalents of the disclosed embodiments, based on the teaching and
guidance presented herein. It is to be understood that the
phraseology or terminology herein is for the purpose of description
and not of limitation, such that the terminology or phraseology of
the present specification is to be interpreted by the skilled
artisan in light of the teachings and guidance presented herein, in
combination with the knowledge of one of ordinary skill in the
art.
* * * * *