U.S. patent application number 10/444402 was filed with the patent office on 2003-10-30 for cold water soluble tea.
This patent application is currently assigned to Lipton, Division of Conopco., Inc.. Invention is credited to Ganesan, Velu, Ganguli, Shovan, Garg, Kush, Patel, Mushtaq, Sinkar, Vilas Pandurang, Subramanian, Narayasaswami.
Application Number | 20030203071 10/444402 |
Document ID | / |
Family ID | 26244185 |
Filed Date | 2003-10-30 |
United States Patent
Application |
20030203071 |
Kind Code |
A1 |
Ganesan, Velu ; et
al. |
October 30, 2003 |
Cold water soluble tea
Abstract
A process for manufacturing a black leaf tea that is infusible
in hot or cold water. The process involves macerating freshly
plucked tea leaves, allowing them to ferment, firing the leaves to
arrest fermentation and then drying them to yield black leaf tea,
wherein the tea leaves are treated with a solubilising compound
selected ascorbic acid, dehydroascorbic acid, 1-scorbamic acid,
5-phenyl-3,4-diketo-gamma-butyrol- actone
(4-phenyl-2,3-diketo-gamma-butyrolactone) or their salts and
mixtures thereof in an amount that is sufficient for the black leaf
tea to be soluble in water at 5 to 100.degree. C.
Inventors: |
Ganesan, Velu; (District
Tinsukia, IN) ; Ganguli, Shovan; (Bangalore, IN)
; Garg, Kush; (District Tinsukia, IN) ; Patel,
Mushtaq; (Karlsruhe, DE) ; Sinkar, Vilas
Pandurang; (Bangalore, IN) ; Subramanian,
Narayasaswami; (Bangalore, IN) |
Correspondence
Address: |
UNILEVER
PATENT DEPARTMENT
45 RIVER ROAD
EDGEWATER
NJ
07020
US
|
Assignee: |
Lipton, Division of Conopco.,
Inc.
|
Family ID: |
26244185 |
Appl. No.: |
10/444402 |
Filed: |
May 23, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10444402 |
May 23, 2003 |
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09815401 |
Mar 22, 2001 |
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6589575 |
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Current U.S.
Class: |
426/52 |
Current CPC
Class: |
A23F 3/10 20130101; A23F
3/08 20130101; A23F 3/14 20130101 |
Class at
Publication: |
426/52 |
International
Class: |
A23K 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 22, 2000 |
IN |
249/MUM/00 |
Apr 27, 2000 |
GB |
0010311.9 |
Claims
We claim:
1. A process for manufacturing a cold water soluble black leaf tea
comprising macerating freshly plucked tea leaves, allowing them to
ferment, firing the leaves to arrest fermentation and then drying
them to yield black leaf tea, the process being characterised in
that the tea leaves are treated with a solubilising compound
selected from the group consisting of ascorbic acid,
dehydroascorbic acid, 1-scorbamic acid,
5-phenyl-3,4-diketo-gamma-butyrolactone or their salts and mixtures
thereof in an amount that is sufficient for the black leaf tea to
be soluble in water at 5 to 100.degree. C.
2. A process according to claim 1 wherein the tea leaves are
treated with the solubilising compound in an amount that is
sufficient for the black leaf tea to be soluble in water at
15.degree. C.
3. A process according to claim 1 wherein the leaves are withered
prior to being macerated.
4. A process according to claim 1 wherein the leaves are treated
with the solubilising compound prior to being macerated.
5. A process according to claim 1 wherein the leaves are treated
with the solubilising compound while the leaves are being
macerated.
6. A process according to claim 1 wherein the concentration of the
solubilising compound is from 0.5 to 10% by weight of tea.
7. A process according to claim 1 wherein the leaves are processed
in the presence of an exogenous oxidative enzyme to enhance the
generation of colour and flavour.
8. A process according to claim 7 wherein the oxidative enzyme is
selected from the group consisting of polyphenol oxidase,
tyrosinase and peroxidase.
9. A process according to claim 1 wherein hydrogen peroxide is
added to enhance the generation of colour and flavour.
Description
FIELD OF THE INVENTION
[0001] This invention relates to a process for obtaining cold water
infusible or extractable tea and to the products obtained thereby
that have good colour and flavour.
BACKGROUND AND PRIOR ART
[0002] Leaf tea may be prepared as green leaf tea or black leaf
tea. Generally, to prepare black leaf tea fresh green leaves of the
plant Camellia sinensis are withered (subjected to mild drying),
comminuted, fermented (in which process enzymes in the tea leaf use
atmospheric oxygen to oxidise various substrates to produce
brown-coloured products) and then fired (to dry the tea leaves).
Green leaf tea is not exposed to the fermentation process. Partial
fermentation may be used to produce intermediate-type teas known as
"oolong" tea.
[0003] Tea is consumed as a hot beverage or a cold beverage such as
iced tea. The numerous compounds in the leaves that give the
beverage its unique organoleptical properties are only sparingly
soluble in cold water so tea is usually infused in water at
temperatures close to 100.degree. C. When iced tea is desired the
tea is infused in water at about 100.degree. C. and then chilled in
a refrigerator for example until it is cold. Unfortunately this can
take several hours.
[0004] Once can prepare iced tea by dissolving the spray dried
liquor obtained at high temperature from black tea or fibres
generated during black tea manufacturing process in cold water.
[0005] United States patent specification U.S. Pat. No. 4,051,264
(Lipton/Sanderson) discloses a method for making a cold water
soluble leaf tea extract. Tea leaves are pre-treated with tannase
under anaerobic conditions to generate a cold-water infusing tea
with good colour, yield and flavour.
[0006] United States patent specification U.S. Pat. No. 3,812,266
(Sanderson/Coggon) discloses a method that involves converting
green tea to black using tannase and natural tea enzymes. The
method also includes a tannase pre-treatment step, but in a slurry
system, followed by oxidation by natural tea enzymes to convert
green tea into black, and generate tea powders, which are both hot
and cold water soluble.
[0007] The article by Tadao Kurata et al in Agr. Biol. Chem, 37
(6), 1471-1477, 1973 discloses that a red pigment is produced at
the initial stage of the browning reaction of dehydro-L-ascorbic
acid (DHA) with alpha-amino acid.
5-phenyl-3,4-diketo-gamma-butyrolactone, which has the same type of
lactone ring structure as dehydro-L-ascorbic acid, is said to give
a similar red colour when reacted with alpha-amino acid. The
pigment is said to have the same structure as the red pigment that
is produced by the oxidation of L-scorbamic acid.
[0008] Tannase is an expensive enzyme and is also not legally
cleared in several countries for usage in tea. In any event, while
this is convenient, for many consumers the quality of the final
beverage is not equal to that prepared from hot infused leaves.
Some consumers prefer not to use powders as they perceive them to
be artificial, unnatural and simply lacking in the romance of
taking tea.
[0009] There is therefore a need for a leaf tea that yields
acceptable tea flavour and colour when infused in cold water.
[0010] The present inventors have now found that one can prepare a
black leaf tea that provides a high quality tea beverage when
infused in hot or cold water by treating tea leaves with one or
more of ascorbic acid, dehydroascorbic acid, 1-scorbamic acid or
5-phenyl-3,4-diketo-gamma-butyr- olactone
(4-phenyl-2,3-diketo-gamma-butyrolactone) or their salts during
black tea manufacture.
STATEMENT OF THE INVENTION
[0011] The present invention can be said in broad terms to relate
to a process for manufacturing a cold water soluble black leaf tea
comprising the steps of macerating freshly plucked tea leaves,
allowing them to ferment, firing the leaves to arrest fermentation
and then drying them to yield black leaf tea, the process being
characterised in that the tea leaves are treated with a
solubilising compound selected from the group consisting of
ascorbic acid, dehydroascorbic acid, 1-scorbamic acid,
5-phenyl-3,4-diketo-gamma-butyrolactone or their salts and mixtures
thereof in an amount that is sufficient for the black leaf tea to
be soluble in water at 5 to 100.degree. C.
[0012] The tea leaves are preferably treated with the solubilising
compound in the presence of oxidative enzymes and/or hydrogen
peroxide to enhance the tea flavour and colour.
[0013] "Tea" for the purposes of the present invention means leaf
material from Camellia sinensis var. sinensis or Camellia sinensis
var. assamica. It also includes rooibos tea obtained from
Aspalathus linearis however that is a poor source of endogenous
fermenting enzymes. "Tea" is also intended to include the product
of blending two or more of any of these teas.
[0014] "Leaf tea" for the purposes of this invention means a tea
product that contains one or more tea origins in an uninfused
form.
[0015] "Cold water soluble" for the purposes of this invention
means giving good colour, flavour and mouthfeel in a short infusion
time i.e. less than 10 minutes, but preferably less than 5 minutes
at a temperature at or above 5.degree. C.
[0016] For the avoidance of doubt the word "comprising" is intended
to mean including but not necessarily "consisting of" or "composed
of". In other words the listed steps or options need not be
exhaustive.
DETAILED DESCRIPTION OF THE INVENTION
[0017] Tea manufacture, especially black tea manufacture,
traditionally comprises: withering, macerating, fermenting and
firing. Black tea for the purpose of the invention is obtained by
the following process.
[0018] Withering is a process whereby the plucked tea leaves are
stored for periods of time (perhaps up to 24 hours), during which
they undergo various biochemical and physical changes which often
includes a loss of moisture. It is optional but preferred.
[0019] Maceration follows the withering step, and traditionally the
withered leaves are optionally rolled to bruise and crush the
leaves i.e. break down the plant tissue structure. This will have
the effect of liberating fermentable substrates and fermenting
enzymes from within the plant cells and tissue. Modern tea
manufacture usually includes this step however the plant cells and
tissue is broken down by passing tea, which has usually been
withered, through a cutting machine. Thus for the purpose of the
invention the green tea leaves may be macerated using a CTC, ball
mill or a grinder or a hammer mill or a LAWRI.TM. tea processor or
a LEGG.TM. cutting machine or rolled using tea rollers as in
orthodox tea processing.
[0020] The next step is commonly called fermentation but that is a
misnomer. "Fermentation" is commonly used in the context of brewing
alcohol to describe the action of exogenous enzymes. However in the
tea world it is used to refer to the oxidative and hydrolytic
process that tea undergoes when certain endogenous enzymes and
substrates are brought together by mechanical disruption of the
cells by macerating of the leaves. During this process colourless
catechins in the leaves are converted to a complex mixture of
yellow and orange to dark-brown substances and producing a large
number of aromatic volatile compounds.
[0021] The fermented product is fired and dried to give a black
leaf tea. The firing involves heating and drying the tea to destroy
the fermenting enzymes and thereby arrest fermentation. It results
in a reduction of moisture content to below 5%, and also leads to
further chemical oxidation and changes in tea aroma. This generally
involves exposing the tea to a blast of hot, dry air in a
dryer.
[0022] The present invention concerns a modification to traditional
black tea manufacture. The modification involves treating the tea
leaves with a solubilising compound selected from the group
consisting of ascorbic acid, dehydroascorbic acid, 1-scorbamic
acid, 5-phenyl-3,4-diketo-gamma-b- utyrolactone or their salts and
mixtures thereof in order to enhance the solubility of the black
tea in cold water.
[0023] The solubilising compound
5-phenyl-3,4-diketo-gamma-butyrolactone referred to in the
aforementioned article in Agr. Biol. Chem, 37 (6), 1471-1477, 1973
by Tadao Kurata et al has oxygen at the 1 position as is common
when labelling heterocyclic compounds. However this compound can
also be labelled as 4-phenyl-2,3-diketo-gamma-butyrolactone,
wherein the keto groups are at the 2 and 3 positions and the phenyl
group is at the 4 position.
[0024] The tea leaves are treated with the solubilising compound
post plucking, preferably prior to an optional but preferable
withering step. The withering step, if desired, preferably tales 1
to 24 hours at 10 to 40.degree. C.
[0025] The compounds are preferably in the form of a solution at a
concentration of from 0.5 to 10% by weight of tea. The solubilising
compound can be applied singly or in split doses. The treatment is
preferably given in the form of a spray or dip.
[0026] The tea is preferably fermented for 10 minutes to 3 hours at
10 to 60.degree. C.
[0027] It is particularly preferred to provide additional oxidative
enzymes and hydrogen peroxide along with the above treatment to
enhance the generation of colour and flavour.
[0028] The oxidative enzymes may be selected from polyphenol
oxidase, tyrosinase and peroxidase of bacterial, fungal or plant
origin at concentrations ranging from 2000 to 100000 units per gram
on the basis of made black tea and hydrogen peroxide at
concentrations ranging from 0.01 to 1% on the basis of made black
tea
[0029] The tea can be dried using any art-known means, preferably
giving leaf tea with a moisture content of less than 5%.
[0030] The products obtained by the above process can be used to
produce instant tea or for infusing black tea in water at
temperatures in the range of 5 to 100.degree. C. The instant tea
can be produced by extracting the tea leaves produced by the above
process with boiling water, clarifying the extract, and drying it.
The instant tea produced by this method will give higher yields of
cold water soluble tea solids having superior tea colour and
flavour than the instant tea produced by the conventional methods.
Water infusions of the tea produced by the process described above
in water at temperatures in the range of 5 to 100.degree. C. will
give tea with superior colour and flavour.
[0031] A first preferred embodiment of the process of the invention
comprises the steps of:
[0032] (a) macerating green tea leaves optionally after withering
for 1-24 hours;
[0033] (b) processing the macerated tea in a conventional manner to
obtain black tea, wherein the green tea is treated with at least
one of ascorbic acid, dehydroascorbic acid, 1-scorbamic acid,
5-phenyl-3,4-diketo-gamma-b- utyrolactone
(4-phenyl-2,3-diketo-gamma-butyrolactone) or their salts in single
or split doses at a concentrate of 0.5 to 10% by wt. of tea
selectively prior to maceration and/or during maceration and/or the
post maceration stages of the above processing of tea depending
upon the quality of the infusibility desired;
[0034] (c) fermenting the macerated tea optionally up to 3 hours at
temperature of 10 to 60.degree. C.; and
[0035] (d) processing the tea in a conventional manner to obtain
black tea.
[0036] A second preferred embodiment of the process of the
invention comprises the steps of:
[0037] (a) macerating the green tea leaves that has been optionally
withered for 1-24 hours;
[0038] (b) treating the macerated green tea with one or more of
ascorbic acid, dehydroascorbic acid, 1-scorbamic acid or
5-phenyl-3,4-diketo-gamma- -butyrolactone
(4-phenyl-2,3-diketo-gamma-butyrolactone) or their salts in single
or in split doses, at a concentration 0.5 to 10% by weight of made
tea;
[0039] (c) fermenting the macerated, treated tea for 10 minutes to
3 hours at a temperature of 10 to 50.degree. C.; and
[0040] (d) processing the material in a conventional manner to
obtain black tea.
[0041] A third preferred embodiment of the process of the invention
comprises the steps of:
[0042] (a) macerating the green tea leaves that has been optionally
withered for 1 to 24 hours at 10 to 40.degree. C.;
[0043] (b) treating the macerated mass with one or more of ascorbic
acid, dehydroascorbic acid, 1-scorbamic acid or
5-phenyl-3,4-diketo-gamma-bytyr- olactone
(4-phenyl-2,3-diketo-gamma-butyrolactone) or their slats in single
or in split doses, at a concentration 0.5 to 10% by weight of made
tea;
[0044] (c) fermenting the macerated, treated tea for 10 minutes to
3 hours at a temperature of 10 to 50.degree. C.; and
[0045] (d) drying the material at 90 to 180.degree. C. to obtain
black tea with a moisture content less than 5%.
[0046] A fourth preferred embodiment of the process of the
invention comprises the steps of:
[0047] (a) macerating the green tea leaves that has been optionally
withered for 1 to 24 hours at 10 to 40.degree. C.;
[0048] (b) treating the macerated mass with one or more of ascorbic
acid, dehydroascorbic acid, 1-scorbamic acid or
5-phenyl-3,4-diketo-gamma-butyr- olactone
(4-phenyl-2,3-diketo-gamma-butyrolactone) or their slats in single
or in split doses, at a concentration 0.5 to 10% by weight of made
tea in the presence of additional oxidative enzymes and hydrogen
peroxide;
[0049] (c) fermenting the macerated, treated tea for 10 minutes to
3 hours at a temperature of 10 to 50.degree. C.; and
[0050] (d) drying the material at 90 to 180.degree. C. to obtain
black tea with a moisture content less than 5%.
[0051] The process of the invention shall now be described with
reference to the following example:
EXAMPLE
[0052] Manufacture of Cold Water Soluble Black Leaf Tea
[0053] Freshly harvested green leaves (1 kg) were withered for 18
hours under ambient conditions and macerated using four cuts on a
CTC. Untreated macerated mass (SAMPLE 1) was processed further by
fermenting on a continuous fermenting unit for 60 minutes followed
by drying on a FBD drier at 135.degree. C. to bring down the
moisture to less than 5% on black tea basis. Treatment was carried
out after first CTC cut (Sample 2) by adding ascorbic acid at 5%
level on the basis of made black tea. The sample was processed
further by fermenting at 25.degree. C. for 60 minutes followed by
drying in a fluidised bed drier at 135.degree. C. for 20 minutes to
bring down the moisture to less than 5% on black tea basis. For
(Sample 3) similar treatment was carried out by processing of green
leaf as for Sample 1, but adding the ascorbic acid solution after
30 minutes of fermentation and allowed to ferment for another 30
minutes and subsequently dried as mentioned in Sample 1 and 2 to
give black tea. In another Sample 4, the ascorbic acid was added at
the end of the fermentation and the sample was dried as described
earlier.
[0054] Process for Preparing Cold Water Infusions
[0055] 1.4 g of black tea samples 1 to 4 were infused in 200 ml of
water at 15.degree. C. for 5 minutes. The solution was filtered to
give cold tea infusions. The colour of infusions obtained from
Samples 1 to 4 was measured using a Hunter Lab Ultrascan XE.TM.
calorimeter. The data is presented in Table 1.
[0056] Process for Preparing Hot Water Infusions
[0057] Only samples 1 and 2 obtained by the process described above
were taken for testing the effect on hot water infusions. Five
grams of tea, 10 grams of sugar, 150 ml of water and 100 ml of milk
were mixed together and heated to boil. The tea liquor was strained
to remove spent tea and colour of the liquor was measured in
reflectance mode at 40.degree. C. in a Hunter Lab Ultrascan XE.TM.
calorimeter. The data is presented in Table 2.
[0058] Colour Measurements
[0059] L*a*b* measurements for colour were carried out on Hunterlab
UltraScan XE.TM. colorimeter under the following conditions:
Cuvette 2 cms (Quartz), Mode Transmittance, Illuminant D65,
Observer 10, Scale CIELAB
[0060] Procedure: 50 ml of the brew was taken in a 2 cm quartz
cuvette, reflectance was measured under the conditions mentioned
above.
1TABLE 1 Effect of the treatment on cold water infusions Sample L*
A* B* Sample 1 76.91 10.09 51.45 Sample 2 65.38 35.76 50.14 Sample
3 61.61 42.69 53.27 Sample 4 62.18 41.48 50.95
[0061] The data in Table 1 show that in samples 2 to 4 the a*
values have been significantly increased indicating that the
infusions will have a deep red colour as compared to the control
(sample 1) which will a very pale yellow colour. Difference of
greater than 1 in `a` value even at a constant value of `L` can be
easily perceived by human eye and sensory panels. Higher L* value
indicates greater depth of colour. Thus the data clearly shows that
treatment of macerated mass at the beginning, during or after the
maceration gives a higher red colour to both cold and hot water
infusions.
2TABLE 2 Effect of the treatment on hot water infusions Sample L*
a* b* Sample 1 52.49 10.82 24.09 Sample 2 54.01 15.79 24.39
[0062] Table 2 further demonstrates the suitability of hot water
infusion of the treated tea (sample 2) produced in accordance with
the process of the invention.
[0063] It is thus possible by way of the present invention to
produce a black leaf tea that infuses well in hot or cold
water.
* * * * *