U.S. patent application number 16/735649 was filed with the patent office on 2020-07-02 for extrusion of agro-food industry byproducts and protein concentrates into value-added foods.
This patent application is currently assigned to CORNELL UNIVERSITY. The applicant listed for this patent is CORNELL UNIVERSITY. Invention is credited to Ilankovan PARAMAN, Syed S.H. RIZVI.
Application Number | 20200205462 16/735649 |
Document ID | / |
Family ID | 54208549 |
Filed Date | 2020-07-02 |
View All Diagrams
United States Patent
Application |
20200205462 |
Kind Code |
A1 |
RIZVI; Syed S.H. ; et
al. |
July 2, 2020 |
EXTRUSION OF AGRO-FOOD INDUSTRY BYPRODUCTS AND PROTEIN CONCENTRATES
INTO VALUE-ADDED FOODS
Abstract
The present invention relates to a process for preparing an
edible foodstuff from food industry waste stream byproducts. This
process involves the steps of: (i) combining, in an extruder, an
extrusion formulation comprising a first food byproduct and at
least one additional ingredient; (ii) introducing supercritical
carbon dioxide (SC--CO.sub.2) into the extruder to mix with the
first food byproduct and the at least one additional ingredient;
and (iii) producing an edible foodstuff containing the first food
byproduct and the at least one additional ingredient, where the
edible foodstuff comprises an extrudate prepared under
supercritical fluid extrusion (SCFX) conditions. The present
invention also relates to a process for preparing an edible
foodstuff from a protein concentrate. The present invention further
relates to edible foodstuffs produced by the various processes
disclosed herein.
Inventors: |
RIZVI; Syed S.H.; (Ithaca,
NY) ; PARAMAN; Ilankovan; (Chesterfield, MO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CORNELL UNIVERSITY |
Ithaca |
NY |
US |
|
|
Assignee: |
CORNELL UNIVERSITY
Ithaca
NY
|
Family ID: |
54208549 |
Appl. No.: |
16/735649 |
Filed: |
January 6, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14657560 |
Mar 13, 2015 |
10524497 |
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16735649 |
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61952615 |
Mar 13, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A23L 19/09 20160801;
A23P 30/20 20160801; A23L 19/07 20160801; A23L 19/01 20160801; A23P
30/34 20160801 |
International
Class: |
A23P 30/20 20060101
A23P030/20; A23P 30/34 20060101 A23P030/34; A23L 19/00 20060101
A23L019/00 |
Claims
1-24. (canceled)
25. A process for preparing an edible foodstuff from a protein
concentrate, said process comprising the steps of: providing, in an
extruder, an extrusion formulation comprising a protein concentrate
in either liquid or powder form; and extruding the protein
concentrate from the extruder in the form of an expanded extrudate
using supercritical carbon dioxide (SC--CO.sub.2) under
supercritical fluid extrusion (SCFX) conditions, thereby yielding
an edible foodstuff comprising the expanded extrudate of the
protein concentrate.
26. The process according to claim 25, wherein the protein
concentrate is milk protein concentrate (MPC).
27. The process according to claim 25, wherein the protein
concentrate is yogurt protein concentrate.
28. The processing according to claim 25, wherein the extrusion
formulation further comprises fruit or vegetable pomace.
29. An edible foodstuff produced by the process according to claim
25.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 14/657,560, filed Mar. 13, 2015, now U.S. Pat. No.
10,524,497, issued Jan. 7, 2020, which claims priority benefit of
U.S. Provisional Patent Application Ser. No. 61/952,615, filed Mar.
13, 2014, the disclosures of which are hereby incorporated by
reference herein in their entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to processes for producing
edible foodstuffs from food industry byproducts and protein
concentrates using supercritical fluid extrusion (SCFX), as well as
the edible foodstuffs produced by these processes.
BACKGROUND OF THE INVENTION
[0003] As the agro-food industries grow worldwide, increasingly
large quantities of fruit-processing byproducts are generated as
waste accounting for 25-40% of the total fruits processed (Bhushan
et al. 2008). These fruit residues, referred to as `pomace`, are
the pulpy solid remaining after the extraction of juice from
fruits, which comprised of peel, seeds, and pulp of the fruit and
contain significant quantity of dietary fiber, natural
antioxidants, phytochemicals (Balasundram et al., 2006; Yu and
Ahmedna, 2013). For instance, around 30-40% apple pomace and 5-11%
sludge of the original fruit is generated as a byproduct in a
typical cider-processing operation (Gassara et al. 2011).
Similarly, grape pomace is a by-product of wine industry accounting
for about 20-25% of the weight of the grape crushed for wine
production (Yu and Ahmedna 2013). While apple pomace has been used
to make citrate, most pomace is viewed as an industrial waste with
very little or no economic value and used either as animal feed or
returned to farms for composting.
[0004] Similarly, the recent phenomenal growth in Greek style
yogurt (GSY) has also created a new problem. For every pound of
Greek style yogurt, 2-3 pounds of whey is generated as byproduct.
Although yogurt whey contains nutritional qualities, it contains
fewer solids than conventional cheese whey, which makes it less
valuable. The disposal of yogurt whey has become a challenge for
the industry. So far, no viable solution has emerged on how to
dispose of millions of pounds of GSY whey that is produced every
day. Furthermore, whey, especially acid whey, generated during
cheese manufacturing also poses disposal problems and its direct
use in value-added products of commercial utility would indeed be
highly desirable. However, until the present invention, such
processes and resulting products have not been developed.
[0005] Various fruits and vegetable pomace, including apple and
grape pomace, are utilized in extrusion applications (Karkle et al.
2012; Altan et al. 2008b; Khanal et al. 2009b). Extrusion
technology is a process of choice to produce a variety of
convenience foods due to its versatility, high productivity, low
cost, and energy efficiency, and is widely used to enhance the
overall digestibility and bioavailability of nutrients (Harper
1981; Brennan et al. 2013). Extrusion is a continuous process that
involves high temperature, short time (HTST) cooking, which can
decrease spoilage microorganisms and inactivate enzymes. During the
process proteins are denatured, starches are gelatinized, and
extrudates are texturally restructured (Min et al. 2007). Because
extrusion provides a continuous process with mechanical shear to
degrade plant cell wall, the insoluble intermolecular network of
fruit pomace is disintegrated and the soluble dietary fiber content
is improved (Hwang 1998). However, pomace addition decreases the
textural qualities of extruded products (Walsh, 2010) and the
high-temperature (130-180.degree. C.), high-shear processing
conditions used in conventional steam extrusion can also destroy
heat sensitive bioactives and nutrients (Onwulata & Heymann,
1994; Alavi & Rizvi, 2009).
[0006] Recently, high-temperature steam-extrusion processing has
been tried as a means to incorporate fruit and vegetable byproducts
in food. However, the high temperatures used led to a loss of
nutritional and sensory qualities.
[0007] As a part of fruit, the pomace has the potential to be
transformed into various ingredients for food applications. For
instance, apple pomace, which consists of peel, core and pulp, can
be converted into various food and industrial ingredients such as
citric acid (Mahawar et al., 2012), pectin (Schieber, 2003);
alcohols (Madrera, 2013), bio-adsorbents (Robinson et al., 2002)
and biofuels (Vendruscolo et al., 2008). However, the economics of
such undertakings is often found to be unattractive for
commercialization of the developed processes. As a rich source of
dietary fiber and phytochemicals, direct utilization of the pomace
in food application can offer an attractive opportunity to both the
processors and consumers. Previous attempts to use fruit pomace in
various food applications over the past decades (Wang and Thomas
1989; Masoodi and Chauhan 1998; Alavi et al., 2011), to the best of
our knowledge, have not materialized into commercial products due
its negative impacts on end-product sensory qualities.
[0008] Extrusion processing as a means of incorporating fruit and
vegetable byproducts in food application is relatively new.
However, the effect of pomace addition on end-product sensory or
nutritional qualities largely varied depending on extrusion
conditions used in processing, pre and post-extrusion treatments,
source of the byproduct, etc. However, the conventional cooking
extrusion used in all the previous studies is based on
high-temperature (130-200.degree. C.) and high-shear (150-300 rpm)
operations. Such extreme processing requirements lead to loss of
sensory and nutritional qualities and lead to products of
undesirable and variable qualities.
[0009] The color pigments and bioactive compounds are typically
sensitive to high heat and shear used in conventional steam
extrusion (Brennan et al., 2011). A wide range of bioactive
compound loss (46-90%) has been reported depending on the severity
of the conventional steam extrusion (Camire et al., 2007; Khanal et
al., 2009a, White et al., 2010). For instance, only 35% of the
total anthocyanin present in the cranberry pomace were retained at
high barrel temperature (190.degree. C.) and screw speed (200 rpm);
the retention was increased to 54% when the barrel temperature was
reduced to 150.degree. C. (White et al., 2010), however, the study
did not indicate the physical characteristics or textural qualities
of the final extruded products. Camire et al., (2007) reported a
90% loss of anthocyanin for extrusion cooking of various fruit
powders. The losses are mainly due to high temperature (170.degree.
C.) and shear (175 rpm) used in the extrusion. Generally, the
phenolic acids are decarboxylated and condensed into tannins at
high temperature processing (Brennan et al., 2011).
[0010] U.S. Pat. No. 8,877,277 to Ganjyal and the related U.S.
Patent Application Publication No. US 2013/0287922 to Ganjyal
(collectively the "Ganjyal disclosures") are directed to a method
of making a food product by forming an expanded extrudate using a
supercritical fluid extrusion process, as well as to the
supercritical fluid extruded food product produced by the method,
but restricted to formulations with starch having very specific
viscosity requirements. The Ganjyal disclosures mention that fruit-
and vegetable-based ingredients can be used in the method, and that
proteins such as whey proteins can also be mixed into various
ingredient formulations. However, the Ganjyal disclosures mention
that post-extrusion processing (e.g., post-extrusion vacuum drying)
was needed when using fruit pomace such as cranberry powder
(pomace) in the extrusion process. Further, in every instance, the
Ganjyal disclosures described the use of a separate hydration step
(i.e., adding water) during the supercritical fluid extrusion
process. There is no mention or suggestion to forego this hydration
step, and no mention of using liquid whey byproduct or even milk
protein concentrate (MPC) as ingredients in the supercritical fluid
extrusion process.
[0011] U.S. Pat. No. 7,220,442 to Gautam et al. ("Gautam") is
directed to a process for preparing a nutrition bar from non-soy
proteins using supercritical fluid extrusion. Gautam teaches that
the non-soy proteins can be from sources such as whey protein,
particularly whey protein isolates and whey protein concentrates.
The supercritical fluid extrusion process of Gautam also requires a
separate water hydration step, including adding water to the whey
protein isolates or the whey protein concentrates. Gautam does not
describe or suggest the use of liquid whey byproduct as an
ingredient in the supercritical fluid extrusion formulations, and
certainly fails to teach or suggest that a liquid whey byproduct
can be used in lieu of water as a source of hydration in the
supercritical fluid extrusion process.
[0012] The present invention is directed to overcoming these and
other deficiencies in the art.
SUMMARY OF THE INVENTION
[0013] The present disclosure generally relates to food extrusion
processes for converting food industry byproducts, as well as
protein concentrates, into edible food products, including, for
example, shelf-stable, puffed products. The present disclosure also
generally relates to the food products produced by the disclosed
processes. In various embodiments, the processes of the present
disclosure are effective in producing food products that are
enriched in dietary fiber and phytochemicals by using low-shear,
low-temperature supercritical fluid extrusion. As described herein,
overall, the process of this invention could serve as a model
system for today's food processing operations to better transform
their byproduct streams into value-added, edible products.
[0014] In one aspect, the present disclosure provides a process for
preparing an edible foodstuff from food industry waste stream
byproducts. This process involves the steps of: (i) combining, in
an extruder, an extrusion formulation comprising a first food
byproduct and at least one additional ingredient; (ii) introducing
supercritical carbon dioxide (SC--CO.sub.2) into the extruder to
mix with the first food byproduct and the at least one additional
ingredient; and (iii) producing an edible foodstuff containing the
first food byproduct and the at least one additional ingredient,
where the edible foodstuff comprises an extrudate prepared under
supercritical fluid extrusion (SCFX) conditions. In accordance with
this process, the first food byproduct is a non-reconstituted
liquid food byproduct, and the additional ingredient optionally
comprises a second food byproduct. In one embodiment of this
process, the extrusion formulation further comprises one or more of
starch, flour, protein concentrate, functional additives, or
flavoring ingredients.
[0015] In another aspect, the present disclosure provides a process
for preparing an edible foodstuff from a protein concentrate. This
process includes the steps of: (i) providing, in an extruder, an
extrusion formulation comprising a protein concentrate in either
liquid or powder form; and (ii) extruding the protein concentrate
from the extruder in the form of an expanded extrudate using
supercritical carbon dioxide (SC--CO.sub.2) under supercritical
fluid extrusion (SCFX) conditions, thereby yielding an edible
foodstuff comprising the expanded extrudate of the protein
concentrate.
[0016] In another aspect, the present disclosure provides edible
foodstuffs produced by the various processes disclosed herein.
[0017] By way of an example, as noted herein, one aspect of the
present disclosure is to provide a process to convert food industry
waste streams (byproducts or co-products) into shelf-stable,
nutrient-enriched extruded products by using a low-shear,
low-temperature supercritical fluid extrusion (SCFX) process. In a
particular embodiment, the process utilizes cheese/yogurt whey and
fruit pomace to directly yield extruded, ready-to-eat products such
as breakfast cereals, healthy snacks, protein puffs, and nutrition
bars, among other food items. The pomace and whey fortified
extruded products of the present disclosure have good textural
qualities and are enriched in fruit-based dietary fiber and
bioactive phytochemicals and milk nutrients. The natural color of
the fruit pomace is preserved in the final products and the process
retains greater than 70% of the total polyphenols and 60% of the
total antioxidants present in the fruit pomace. The novel
combination of SCFX and agro-industry waste streams offers a unique
combination to effectively preserve and utilize the nutritionally
attractive byproducts as a source of functional ingredients in
extruded products, while adding value to the industrial waste
streams.
[0018] One advantage that makes this process of the present
disclosure unique is that liquid whey (which contains protein as
well as other non-protein components) takes the place of water in
the SCFX process, which at this time is a significant waste product
of the `Greek` yogurt industry. The use of liquid whey is
beneficial since the dehydration and drying of whey, as used in
most other products that use whey, leads to destruction of
nutrients due to the drying process. The drying and dehydration
process is also energy intensive.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The patent or application file contains at least one drawing
executed in color. Copies of this patent or patent application
publication with color drawings will be provided by the U.S. Patent
and Trademark Office upon request and payment of the necessary
fee.
[0020] FIG. 1 is a flowchart for recovering food grade apple pomace
from apple juice processing.
[0021] FIG. 2 is a flowchart for recovering food grade grape pomace
from wine processing.
[0022] FIG. 3 is a schematic of supercritical-CO.sub.2 extrusion
process used to produce extruded products fortified with pomace and
liquid whey.
[0023] FIG. 4 are photographs of starch-alone, apple pomace, green
grape pomace, red grape pomace extruded products made by SCFX
process.
[0024] FIG. 5 is a comparison of apple pomace and grape pomace
extrudates with water and cheese whey processed by SCFX.
[0025] FIGS. 6A-6C are photographs of fruit pomace, finely ground
dried pomace, and extruded products made of (A) apple (FIG. 6A),
(B) red grape pomace (FIG. 6B), (C) and green pomace (FIG. 6C).
[0026] FIGS. 7A-7B are bar graphs illustrating a retention of total
phenolics (FIG. 7A) and anti-oxidant capacity (FIG. 7B) of pomace
extrudates before and after supercritical fluid extrusion
processing.
[0027] FIG. 8 are scanning electron micrographs illustrating the
internal morphology of control (0% SC--CO.sub.2) puffed (1%
SC--CO.sub.2) apple pomace product made by SCFX.
[0028] FIG. 9 are scanning electron micrographs of puffed product
made by SCFX with 1% SC--CO.sub.2: apple pomace extrudate (left
panel), grape pomace extrudate (middle panel), and starch-alone
extrudate (right panel). Micrographs in the upper and lower rows
represent low (.about.25.times.) and high (.about.60.times.)
magnifications, respectively.
[0029] FIG. 10 are photographs of flavored apple or grape pomace
incorporated extruded puffs made by SCFX.
[0030] FIG. 11 is a photograph of a pilot-scale Wenger TX-52 Magnum
co-rotating twin-screw SCFX system used to produce extruded
products containing fruit pomace and liquid cheese whey.
[0031] FIG. 12 is a photograph of MPC- and starch-based fruit
pomace extrudates made by SCFX. * Due to limited quantity of grape
pomace, purple and green grape pomace were used in MPC- and
starch-based extrudates, respectively
[0032] FIG. 13 is a photograph of pomace and liquid whey
incorporated MPC extrudates made by SCFX. Liquid whey was
concentrated acid whey with .about.20 wt. % total solids and pH of
4.2.
[0033] FIG. 14 are scanning electron micrographs of grape-pomace
and cheese-whey incorporated puffed MPC and starch-based extrudates
made by SCFX with 1% SC--CO.sub.2.
DETAILED DESCRIPTION OF THE INVENTION
[0034] The present disclosure relates to, inter alia, processes for
producing edible foodstuffs from food industry byproducts and
protein concentrates using supercritical fluid extrusion (SCFX), as
well as the edible foodstuffs produced by these processes.
[0035] As provided, the processes of the present disclsoure utilize
the SCFX process, which is a modified process utilizing
supercritical fluids such as supercritical carbon dioxide
(SC--CO.sub.2) as an expansion agent instead of steam. The process
produces highly expanded, low-density products at process
temperatures below 100.degree. C. along with low shear conditions
(Rizvi et al., 1992, Rizvi et al., 1995). Therefore, heat- or
shear-sensitive nutrients and bioactives can be effectively
incorporated to produce nutrient enriched products without much
nutrient loss (Alavi & Rizvi, 2009, Cho & Rizvi, 2010,
Paraman et al., 2012, Paraman et al., 2013). The mild operating
requirements are particularly advantageous to process fruits,
vegetables, and their byproducts (e.g., fruit and vegetable pomace)
with enhanced nutritional and sensory qualities, along with whey as
a replacement for water, which is required during extrusion
processing. Thus, the present disclosure provides a process
effective for, inter alia, recapturing economic benefits of fruit
and vegetable pomace via efficient utilization and value
addition.
[0036] As provided, the present disclosure relates to processes
that yield expanded extrudates, particularly those based on fruit,
vegetable, and dairy industry byproducts, by incorporating them
directly into shelf-stable, puffed, extruded products. These
processes yield expanded extrudates that have high nutritional
profiles and sensory qualities, compared to products based on
different process mechanisms. Unlike the processes of the present
disclosure, no processes used or proposed for use to date in the
food industry have been able to provide expanded extrudates from
pomace and whey having such high nutritional qualities, texture and
sensory properties. Nor have processes known to date been proposed
to obtain such products at low temperature and with unique
texture.
[0037] Compared to conventional high-temperature food extrusion
processes, the present disclosure's use of SCFX processes involving
supercritical CO.sub.2 is processed at lower, sub-steam
temperatures, allowing for the retention of phenolics and other
phytochemicals in the end product.
[0038] Whey and pomace as used by the processes of the present
disclosure can be used in formulations to yield a fortified product
and have good textural qualities (due to the plasticizer property
of liquid whey and SCFX process) and are enriched in dietary fiber,
bioactive phytochemicals, milk protein and nutrients. The natural
color of the fruit pomace is preserved in the final products and
the end product as made by this process retains over 80% of the
total polyphenols and over 70% of the total antioxidants present in
the fruit pomace.
[0039] The novel combination of SCFX and agro-industry waste
streams offers a unique combination to effectively preserve and
utilize the nutritionally attractive byproducts as a source of
functional ingredients in extruded products while adding value to
the industrial waste streams.
[0040] Further aspects of the processes and edible foodstuffs of
the present disclosure are summarized below, as follows:
[0041] The present invention describes a process for novel
utilization of the byproducts generated during food and
agro-processing operations such as manufacture of yogurt, cheese,
wine and fruit juice industries (whey and fruit pomace) into puffed
ready-to-eat extruded products without compromising their
nutritional qualities. The byproducts are utilized as a source of
dietary fiber, phytochemicals, and milk nutrients in the extruded
products. Supercritical fluid extrusion (SCFX) was used to process
the byproducts into shelf-stable products, which produced expanded,
low-density products with good textural qualities at temperatures
(.about.100.degree. C.), much lower than that used in conventional
cooking extrusion (130-200.degree. C.). The process of
incorporating the complementary streams of fruit pomace and
concentrated whey provide puffed crunchy products with a balanced
nutritional profile. The extruded products are very light in weight
with 0.19-0.35 g/cm.sup.3 density and contain 14 g dietary fiber,
93 mg gallic acid equivalent polyphenols, and 652 mg vitamin C
equivalent antioxidants in 100 g products.
[0042] The process offers simple and straight forward method to
utilize the byproducts for food applications. The liquid whey may
be concentrated and pumped directly into extruder barrel in lieu of
water while processing cereal, snack food or protein based
formulations fortified with finely ground fruit pomace up to 10-40%
by dry weight. The overall process compromises the following steps:
preparing food grade pomace with high nutrient retention, making
finely ground pomace powders, preferably concentrating
cheese/yogurt whey to 10-30% total solids, introducing the dry
formulation into extruder barrel, adding the liquid whey directly
into extruder barrel, processing the mixtures of the feed streams
in an extruder to form a mass at low-temperature, low-sheer
conditions (80-90.degree. C., 100-120 rpm), incorporating
supercritical carbon dioxide (SC--CO.sub.2) into the dough at high
pressure (7.6-10.3 MPa), extruding the SC--CO.sub.2 incorporated
product through shaped die inserts, and cutting them into various
sizes to achieve expanded products.
[0043] The ingredient formulations and extrusion process parameters
can be tuned and adjusted to produce a variety of extruded products
enriched with fruit pomace and whey, acidic or sweet. The processes
described below outline our invention to make ready-to eat
products, sweet and savory extruded products fortified with fruit
pomace and liquid whey. While the process/product disclosed here
uses apple and grape pomace, the generic process is also applicable
to utilization of other fruit or vegetable products/byproducts in
extruded products.
Process for Preparing Edible Foodstuffs from Food Industry By
Products
[0044] In one aspect, the present disclosure provides a process for
preparing an edible foodstuff from food industry waste stream
byproducts. This process involves the steps of: (i) combining, in
an extruder, an extrusion formulation comprising a first food
byproduct and at least one additional ingredient; (ii) introducing
supercritical carbon dioxide (SC--CO.sub.2) into the extruder to
mix with the first food byproduct and the at least one additional
ingredient; and (iii) producing an edible foodstuff containing the
first food byproduct and the at least one additional ingredient,
where the edible foodstuff comprises an extrudate prepared under
supercritical fluid extrusion (SCFX) conditions.
[0045] Supercritical fluids have desirable properties such as
gas-like diffusivity and viscosity and liquid-like density and are
utilized in a variety of food and industrial applications (Brunner,
2005). Carbon dioxide (CO.sub.2) is the most common supercritical
fluid and is regarded as an inert, non-toxic, naturally abundant,
tunable, and non-flammable solvent with relatively low critical
pressure (7.38 MPa) and temperature (31.1.degree. C.) (Zhang and
Han 2013). Supercritical fluid extrusion (SCFX) combines extrusion
processing with supercritical fluids to overcome the limitations of
the conventional high temperature steam extrusion. This is achieved
by incorporating supercritical CO.sub.2 as a blowing agent instead
of steam (Rizvi et al. 1995; Alavi and Rizvi 2005). Since the SCFX
process produces low density expanded products at low-temperature
and -shear conditions, which allows incorporating heat and shear
sensitive ingredients such as proteins (Paraman et al. 2013) and
micronutrients (Paramen et al. 2012) in extruded products.
Similarly, fruit pomace and fruit-based ingredients can be
incorporated as a source of dietary fiber and nutrients to produce
expanded, shelf-stable, functional extruded products and breakfast
cereals at temperatures below 100.degree. C.
[0046] Various parameters (e.g., temperature, pressure, speed) of
the SCFX conditions are as described generally and in more detail
in the present disclosure. In particular embodiments, the SCFX
conditions involve maintaining the extrusion formulation at a
temperature of not greater than 100.degree. Celsius during the
process of the present disclosure. In another embodiment of the
disclosed process, the SC--CO.sub.2 is introduced at a constant
flow rate. In a further embodiment of the disclosed process, the
SC--CO.sub.2 is introduced under a high pressure of between about
7.6-10.3 MPa.
[0047] In accordance with this process, the first food byproduct is
a non-reconstituted liquid food byproduct, and the additional
ingredient optionally comprises a second food byproduct.
[0048] As used herein, a "food byproduct" refers to a waste stream
byproduct resulting from a process in the food industry for
yielding a primary food product for consumption by a human or
animal. By way of an example, as used herein, a "food byproduct"
would include "liquid whey" that is produced as a waste stream
byproduct in the process for making yogurt (e.g., Greek yogurt) or
cheese, where the yogurt and cheese are the primary food products
and the liquid whey is the waste stream byproduct yieled during the
process. A further example of a "food byproduct" is "pomace" which
is yielded when producing final products from fruits or vegetables.
Thus, "fruit pomace" and "vegetable pomace" are also considered
"food byproducts" in accordance with the present invention.
[0049] As used herein, the term "liquid whey," which is also
referred to as milk serum or milk permeate, is the liquid remaining
after milk or cultured milk products have been curdled and
strained. It is a byproduct of the manufacture of casein, cheese,
and other cultured milk products such as yogurt. As provided
herein, liquid whey is also referred to in various embodiments of
the present disclosure as a non-reconstituted liquid food
byproduct. As used in accordance with the present disclosure,
liquid whey as a byproduct is different and distinct from whey
protein or rehydrated whey or rehydrated whey protein. As discussed
elsewhere herein, at the time of the present disclosure, no other
teaching, suggestion, or motivation was known in the food industry
field that would have prompted one of ordinary skill in the art to
use liquid whey in an SCFX process in lieu of water, thereby
enabling SCFX extrusion without requiring the hydration step used
in conventional SCFX processes.
[0050] Thus, unlike conventional SCFX processes, and for the first
time known in the food extrusion field, the process of the present
disclosure does not require a separate hydration step to yield the
extrudate. Instead, as set forth in more detail herein, in certain
embodiments, a non-reconstituted liquid food byproduct,
particularly liquid whey, is used in lieu of water in the SCFX
process.
[0051] As set forth above, the process involves the use of a first
food byproduct as one of the components of the extrusion
formulation. A suitable first food byproduct can include, without
limitation, a non-reconstituted liquid food byproduct. As used
herein, the term "non-reconstituted liquid food byproduct" refers
to a food byproduct that is in liquid form and that has not been
reconstituted by adding water or some other hydration agent.
[0052] In accordance with one embodiment of this process, the
non-reconstituted liquid food byproduct (i.e., the "first food
byproduct") is liquid whey. Suitable examples of liquid whey for
use in the present process can include, without limitation, liquid
cheese whey, liquid yogurt whey, or sweet whey.
[0053] In a particular embodiment, the process of the present
disclosure uses an extrusion formulation that comprises between
about 2 and about 20 percent by dry weight of the liquid whey. In
another embodiment, the liquid whey is concentrated to between
about 10 and about 40 percent by dry weight prior to the combining
step of the process.
[0054] In accordance witih another embodiment of this process, the
at least one additional ingredient is a second food byproduct.
Suitable examples of second food byproducts for use in the
disclosed process include, without limitation, fruit pomace,
vegetable pomace, or a combination of fruit and vegetable pomace.
In a more particular embodiment, the extrusion formulation
comprises between about 10 and about 40 percent by dry weight of
the fruit pomace, vegetable pomace, or the combination of fruit and
vegetable pomace.
[0055] As discussed herein, fruit pomace is a byproduct that
remains after juice extraction from fruits and constitutes about
20-25% of the fresh fruit weight. It is treated as an industrial
waste with very little or no economic value and used either as
animal feed or returned to farms for composting. Since pomace
contains large amount of water (66.4-78.2%, wet basis) and
fermentable sugars (3.6%, wb), its direct disposal into soil
creates environmental concerns due to the uncontrolled fermentation
and high chemical oxygen demand during its degradation, 300 g
COD/kg pomace. Therefore, the process of the present disclosure
provides an environmental friendly way to use pomace to create
value-added foods.
[0056] As used herein, suitable examples of fruit pomace for use in
the disclosed process can include, without limitation, pomace
yielded from fruits such as apples, grapes, pears, plums, bananas,
peaches, apricots, oranges, mangoes, papayas, melons, berries,
tomatoes, nectarines, figs, dates, grapefruits, clementines,
pineapple, and ugli fruit, or any other fruit with skin and
seeds.
[0057] As used herein, suitable examples of vegetable pomace for
use in the disclosed process can include, without limitation,
pomace yielded from vegetables such as carrots, peppers, beets,
broccoli, cucumber, squash, corn, potatoes, sweet potatoes, peas,
beans, pumpkins, zucchinis, turnips, rutabagas, and parsnips, or
any other root crop.
[0058] In a particular embodiment of the disclosed process, the
first food byproduct is liquid whey and the second food byproduct
is fruit pomace or vegetable pomace.
[0059] In one embodiment of this process, the extrusion formulation
further comprises one or more of starch, flour, protein
concentrate, functional additives, or flavoring ingredients.
[0060] As used herein, suitable protein concentrates used in the
extrusion formulation of this process can include, without
limitation, milk protein concentrate (MPC) and whey protein
concentrate (WPC).
[0061] In one embodiment of the disclosed process, the at least one
additional ingredient comprises milk protein concentrate (MPC).
[0062] In another embodiment of the disclosed process, the at least
one additional ingredient comprises both milk protein concentrate
(MPC) and fruit pomace or vegetable pomace.
[0063] In another aspect, the present disclosure provides an edible
foodstuff produced by this process. Various attributes of the
edible foodstuff are set forth herein. In a particular embodiment,
the edible foodstuff comprises an expanded extrudate having an
internal microstructure that is substantially uniform in air cell
distribution, size, and density.
[0064] In another embodiment, the edible foodstuff retains at least
50 percent of antioxidant and/or phenolic content as compared to
that present in the at least one additional ingredient, wherein
said additional ingredient is fruit or vegetable pomace.
[0065] In a further embodiment, the edible foodstuff is a puffed
and ready-to-eat product. By way of example, the edible foodstuff
can include, without limitation, a breakfast cereal, a healthy
snack, a protein puff, and nutrition bar. In various embodiments,
the edible foodstuff is shelf-stable.
[0066] As described herein, in various embodiments of the process,
liquid whey is used as substitute for water, which is normally used
in the separate hydration step in convention SCFX processes. The
present disclosure is the first known use of liquid whey in this
manner, with the present disclosure teaching, for the first time,
the advantages of using liquid whey in an SCFX process for the food
extrudation field.
[0067] As described herein for the first time, the direct
utilization of the liquid whey in the extrusion process of the
present disclosure provides energy conservation to the overall
process by bypassing the drying step of liquid whey to whey solids.
In various embodiments, the liquid whey may be concentrated to
varying levels of the total solids and used directly into extruded
products. As provided herein, liquid whey improves the overall
nutritional quality of the final extruded products. For example,
liquid whey contains milk nutrients such as peptides, proteins,
sugars, vitamins, and minerals. Further, as provided herein, the
liquid whey acts as a plasticizer to provide final products with
balanced textural qualities (e.g., adequate hardness, less
brittleness) required for end-product intactness during handling
and storage, which is essential in certain cases in terms of
industrial productivity standards.
[0068] More particularly, in one aspect, the present disclosure
provides a process to convert the byproducts generated from yogurt,
cheese, wine and fruit juice industries into nutritionally
superior, shelf-stable expanded extruded products. The process
converts agro-industry byproducts such as the pomace directly into
extruded products while also optionally using liquid whey in lieu
of water during extrusion processing and as a source of added
nutrients.
[0069] The utilization of the liquid whey provides, inter alia, the
following advantages to the process: energy conservation; use of
whey as a plastacizer without the need for a separate water
hydration step; and improved nutritional qualities of the edible
foodstuff product. These advantages of the process of the present
disclosure are described in more detail below.
[0070] Energy Conservation:
[0071] Whey is typically dehydrated and used into extruded products
with re-added water (Onwulata et al., 1998). The present invention
directly utilizes whey as is or concentrated to varying level of
solids and thus bypassing the drying step which is expensive and
leads to nutrient destruction.
[0072] Whey as a Plasticizer:
[0073] Water acts as a plasticizer during extrusion processing. The
present invention utilizes liquid whey as a plasticizer instead of
water. The lactose and protein in the concentrated liquid whey
solids provide final products with balanced textural qualities
(adequate hardness, less brittleness) required for end-product
intactness during handling and storage, which is essential in terms
of industrial productivity standards.
[0074] Improved Nutritional Qualities:
[0075] Incorporating yogurt/cheese liquid whey improves the overall
nutritional quality of extruded products as it contains milk
nutrients (peptides, proteins, sugars, vitamins, and minerals)
(Table 2). The liquid whey is concentrated to varying level of the
total solid contents and used directly into extruded products.
[0076] Thus, the present disclosure offers a process to produce
consumer acceptable ready-to-eat products with balanced nutrients
derived from inexpensive edible byproducts. The fruit pomace
contains higher amounts of soluble dietary fiber and bioactive
phytochemicals compared to those in cereal grains. Thus, the pomace
incorporated extrudates provide low-density, puffed products that
are enriched in dietary fiber and phytochemicals.
[0077] The natural fruit color is retained in the final product,
indicating the preservation of color pigments and the associated
bioactive compounds (FIGS. 4-6). About 84% of the total polyphenols
and 74% of the total antioxidants of the fruit pomace are also
preserved in the extrudates (FIG. 7). The preservation of the above
said properties are significantly higher than those reported in
conventional steam extruded products; the loss of bioactive
compounds reported in the literature ranges from 46 to 90% (Camire
et al., 2007; Khanal et al., 2009a, White et al., 2010). Therefore
the extruded products produced in the present invention can serve
as functional cereals.
[0078] By incorporating milk nutrients (e.g., peptides, proteins,
sugars, vitamins, and minerals) present in yogurt/cheese whey, the
overall quality of extruded products is further improved; the rich
amount of minerals in whey can also help reduce the need of added
salt in extruded savory products.
[0079] By utilizing a modified low-temperature supercritical
CO.sub.2 (SC--CO.sub.2) extrusion, the process is able to maintain
the nutritional and sensory qualities of the formulation
ingredients used to make the final products. The process,
therefore, offers unique nutrient enriched, puffed products while
providing opportunities to local processors to better utilize their
byproducts sustainably.
[0080] In certain embodiments of the present disclosure, the
resulting extruded products were very light in weight with
0.19-0.27 g/cm.sup.3 piece density and expanded well with an
expansion ratio of 7.7-8.4, providing comparatively better textural
qualities compared to those made by conventional steam extrusion.
Previous studies reported that addition of pomace reduced radial
expansion ratio (4-6) of the extrudates made by conventional
extrusion (Karkle et al., 2012; Altan et al., 2008a).
[0081] In certain embodiments, the expanded extrudates made in the
present invention have unique internal microstructure (uniform air
cell distribution, size, and density) compared to the conventional
steam extrusion; the air cells are small in size (128-176 .mu.m)
and distributed uniformly throughout the products (FIGS. 8-9),
which is due to the less forceful, controlled puffing nature of
supercritical fluid extrusion. The unique internal cell structure
of the extrudate is an indicative of improved textural and sensory
attributes. On the other hand most typical puffed products
generated by conventional steam expansion have large air cells
(0.5-1.0 mm diameter) with less uniform internal micro-structure
(Karkle et al., 2012).
[0082] The added pomace and whey solids provide final products with
balanced sensory attributes (expansion, crispy/crunchiness) and
textural qualities (adequate hardness, less brittleness) required
for end-product intactness during handling and storage, which can
be essential in terms of industrial productivity standards.
[0083] The extruded products can be further cut into crisps for use
as functional food ingredients in various product applications such
as nutrition bars, desert toppings, salads, baked products, etc.
Such nutrient enriched extruded products can serve as delivery
vehicles to overcome nutritional deficiencies in targeted
populations.
Process for Preparing Edible Foodstuffs from Protein
Concentrates
[0084] In another aspect, the present disclosure provides a process
for preparing an edible foodstuff from a protein concentrate. This
process includes the steps of: (i) providing, in an extruder, an
extrusion formulation comprising a protein concentrate in either
liquid or powder form; and (ii) extruding the protein concentrate
from the extruder in the form of an expanded extrudate using
supercritical carbon dioxide (SC--CO.sub.2) under supercritical
fluid extrusion (SCFX) conditions, thereby yielding an edible
foodstuff comprising the expanded extrudate of the protein
concentrate.
[0085] In accordance with this process, in various embodiments, the
protein concentrate is milk protein concentrate (MPC). In various
other embodiments, the concentrate is yogurt concentrate
(powder).
[0086] In certain other embodiments of this process, the extrusion
formulation further includes fruit or vegetable pomace. Suitable
examples of the types of fruit and vegetable pomace are as set
forth herein.
[0087] In another aspect, the present disclosure provides an edible
foodstuff produced by this process.
[0088] Further aspects of this process of the present disclosure
and the edible foodstuff produced by this process are also
described in Example 2.
EXAMPLES
[0089] The following examples are intended to illustrate particular
embodiments of the present invention, but are by no means intended
to limit the scope of the present invention.
Example 1
Liquid Whey and Fruit Pomace in the Production of a Foodstuff
[0090] Various aspects of the process for using liquid whey and
fruit pomace to produce a new and nutritious foodstuff are outlined
below, as follows:
[0091] (i) Fruit pomace preparation. Apple and grape pomace was
obtained from the New York State Agricultural Experiment Station
juice and wine processing pilot plants (Geneva, N.Y.). The
byproducts are processed by similar processes described in FIG. 1
and FIG. 2. The wet apple pomace contained a moisture content of
71% and pH of 4.8. The grape pomace contained a moisture content of
76%. The pH was 3.3-3.8. The fruit pomaces were dried in a hot air
oven at 40.degree. C. for 48 hours to moisture content of 5-8%. The
dried pomaces were finely ground with a hammer mill to pass through
a 0.031 inch screen.
[0092] (ii) Acid whey preparation. Acid whey generated from our
dairy processing facility was concentrated to a desired total solid
content by using a low-temperature vacuum evaporator. The
concentrated whey contained .about.10-30% total solid content (%,
dw) and pH of 4.2.
[0093] (iii) Feed formulation. Extrusion formulations consisting
10-40% fruit pomace by dry-weight and other required dry
ingredients (70-76% starch, 2% functional additives, <1%
flavoring ingredients) were mixed for 9 minutes in 0.14 m3 ribbon
blender (Littleford Day Inc., Florence, Ky., USA) to ensure uniform
mixing.
[0094] (iv) Supercritical fluid extrusion (SCFX). The dry-blend
formulations were extruded by using a pilot-scale Wenger TX-52
Magnum co-rotating twin screw extruder (Wenger Manufacturing,
Sabetha, Kans., USA) with a length to diameter ratio (L/D) of
28.5:1 (Rizvi et al., 1995). A block diagram of the screw profile
with extrusion parameters is shown in FIG. 3. The extruder was
operated at a feed rate of 35 kg/h and screw speed of 100-120 rpm.
The barrel temperature in the all 5 barrel zones were set to
maintain at .about.25.degree. C. by circulating chilled brine
(-10.degree. C.) through barrel jackets.
[0095] (v) The concentrated whey was directly pumped into the
extruder barrel while processing the fruit pomace in the extruder
at flow rate of 20-40% of the dry-feed flow rate, which will give
dough water content of 18-32%.
[0096] (vi) A pilot scale supercritical fluid system was used to
generate and inject SC--CO.sub.2 at a constant flow rate
(7.6.times.10-5 kg/s) into the barrel through four valves located
at L/D of 24. The SC--CO.sub.2 was injected at pressure of 1100 psi
(7.58 MPa) to maintain a continuous flow of SC--CO.sub.2 into the
product melt (Rizvi et al., 1995).
[0097] (vii) The product temperature at the die-exit was
.about.80-90.degree. C. A flow restrictor was used to maintain the
die pressure at .about.10 MPa (1500 psi). The product melt was
forced through one die insert with 4.2 mm diameter circular
openings and cut by 2 bladed knife rotating at 600-900 rpm to
obtain ball shaped products. The final products were dried at
85.degree. C. to .about.5-8% moisture content.
[0098] Product Characterization:
[0099] Piece density of the extrudates was measured using the sand
displacement method; piece density was defined as the ratio of the
mass of the sample to that of its volume that includes internal
pores but excludes the void or space among the pieces. Bulk density
of the extruded pomace was measured by filling a container of known
volume with the product; bulk density is defined as the mass of the
particles divided by the volume they occupy that includes internal
pores plus the space between the particles. The procedure was
repeated five times for each set of samples. Expansion ratio was
calculated by dividing the cross sectional area of the extrudates
by the cross-sectional area of the die opening. An average diameter
of 10 samples was used to determine the expansion ratio of each set
of samples.
[0100] The textural properties of the pomace puffs were measured
using a TA-XT2 texture analyzer and Texture Exponent 32 software
(Micro Systems, Godalming, UK). The extruded puffs were
equilibrated in a humidity chamber containing saturated calcium
chloride (30% RH) for 48 h and compressed to 80% of their average
original diameter using a 35 mm compression plate at a test speed
of 0.2 mm/s. The peak force (N), number of peaks, and initial
gradient (N/mm) of the force-deformation curve were recorded and
analyzed to calculate the hardness, crispiness, and compression
modulus of the products, respectively. An average of 12 samples was
used to determine the properties.
[0101] Total phenolic contents were determined by the
Folin-Ciocalteu assay (Singleton and Rossi 1965). The antioxidant
capacities of the pomace and the extrudates were evaluated using
the method described by Prior et al., 2005. The internal
microstructures of the pomace extrudates were observed by LEICA 440
scanning electron microscope. The samples were cut into a thin
slice, mounted on aluminum stubs with double-sided adhesive tape,
coated with gold-palladium, and examined at an intensity of 5
kV.
Apple and Grape Pomace Extrudates
[0102] Nutrient Retention.
[0103] The appearance of the puffed extruded products of apple,
green grape, purple grape pomace are shown in FIGS. 4-6. As may be
noted, the natural color of the pomace was preserved during the
whole production process, indicating that the overall production
process used in this process retained the color and the associated
bioactive nutrients in the final products. The color pigments and
bioactive compounds are typically sensitive to heat and shear used
in conventional steam extrusion. The low-temperature and low-shear
conditions used in the present SCFX process protected the product
color and nutrient.
[0104] From the data provided in FIG. 7, it can be seen that our
pomace incorporated products, the process retained 84% of the total
phenolics and 74% of total antioxidants present in the pomace. The
losses were significantly lower than those reported in conventional
steam-based extrusion. Depending on the severity of the
conventional steam extrusion, a wide range of bioactive compound
loss (46-65%) has been reported. Therefore the present invention
provides an effective process-based strategy to fortify the heat
sensitive bioactive phytochemicals and nutrients in low-moisture
(5-8%) expanded products.
[0105] Nutrient Enrichment.
[0106] Nutrient content of the apple and grape pomaces are given in
Table 1. The composition of the cheese acid and sweet whey is given
in Table 2. The estimated nutrient content of the resulting pomace
and whey incorporated SCFX-generated puffed products are given in
Table 3. Also shown for comparison purposes in Table 3 is a typical
composition of commercial puffed cereal product. As may be noted,
by incorporating pomace to produce the puffed products, the dietary
fiber content increased from 0.8 to 14 g/100 g product compared to
the control commercial product. Since 14% fiber was incorporated in
the extruded puffed products, the pomace incorporated products can
be considered as healthy functional food as well as `whole grain`
functional cereals.
TABLE-US-00001 TABLE 1 Typical composition of apple and grape
pomace .sup.a White grape Red grape Apple pomace pomace Composition
pomace (Muller Thurgau) (Pinot Noir) Total dietary fiber (%, dwb)
83.3 28.0 56.3 Insoluble dietary fiber (%) 63.3 27.3 54.6 Soluble
dietary fiber (%) 20.0 0.72 1.7 Protein (%) 6.4 6.5 12.1 Fat (%)
5.4 2.6 4.7 Soluble sugars (%) 2.3 55.8 1.4 Minerals (%) 1.4 2.5
6.2 Condensed Tannins (%) 4.2 8.5 19.8 Polyphenolic compounds 3.8
15.8 21.4 (mg GAE/g DW) .sup.b Antioxidant 12.7 capacity (ABTS) (mg
VCE/g DW) .sup.b .sup.a Adapted from, Bibbins-Martineza 2010, Deng
et al., 2011, Karkle et al., 2012; .sup.b Experimental values. GAE
= gallic acid equivalent, VCE = vitamin C equivalent
TABLE-US-00002 TABLE 2 Composition of sweet and acid cheese whey
Composition Sweet whey Acid whey Water (%, wb) 93-94 94-95 Dry
matter (%, wb) 6-6.5 5-6 Lactose (%, wb) 4.5-5 3.8-4.3 Lactic acid
(%, wb) traces up to 0.8 Total protein (%, wb) 0.8-1.0 0.8-1.0 Whey
protein (%, wb) 0.6-0.65 0.6-0.65 Citric acid (%, wb) 0.1 0.1
Minerals (%, wb) 0.5-0.7 0.5-0.7 pH (actual acidity) 6.2-6.4
4.6-5.0 Soxhlet-Henkel value about 4 20-25 of titrable acidity
TABLE-US-00003 TABLE 3 Estimated nutrient composition of apple
pomace incorporated extrudates and commercial sample .sup.a Apple
pomace Apple pomace and cheese Commercial extrudate whey extrudate
Jax (g/100 g (g/100 g (g/100 g Nutrients product) .sup.b product)
.sup.c product) .sup.d Total dietary fiber 14.2 14.2 0.1 Protein
1.5 2.4 7.1 Fat 1.2 1.6 38.8 Carbohydrates 77.4 81.3 49.4 Soluble
sugars/lactose 0.5 4.4 -- Minerals 0.3 0.9 -- Condensed Tannins 0.9
0.9 -- Polyphenolic 80 80 -- compounds (mg GAE/100 g DW)
Antioxidant 280 280 -- capacity (ABTS) (mg VCE/100 g DW) Total
calories 376.4 388.0 564.4 .sup.a Calculated based on ingredient
composition on dry weight basis, .sup.b Formulations containing 22%
apple pomace, 76% pregel starch, 1% lecithin, and 1% distilled
monoglycerides. .sup.b Formulations containing the above
formulation with added liquid whey at 5.1% on dry weight basis.
.sup.d Bachman Cheese Flavored Corn Snacks, Crunchy Jax Twists
[0107] Similarly phytochemicals and milk-based mineral contents
improved significantly. The extruded products contained 93 mg
gallic acid equivalent polyphenols, and 652 mg vitamin C equivalent
antioxidants in 100 g final products when incorporating 22% apple
pomace. The total calories of the pomace incorporated products
decreased to 376.4 calories/100 g compared to the commercial
product (564.4 calories/100 g). The fat content of the pomace
incorporated products were only 1.5% compared to that of commercial
product (38.8%). The fruit pomace incorporation in extruded
products significantly enhanced the nutritive value of the final
products and their health potentials.
[0108] Physical Characteristics.
[0109] The textural characteristics of the pomace and cheese whey
incorporated puffed products are given in Table 4 (apple pomace
products) and Table 5 (grape pomace products). All the puffed
products produced by SCFX gave the best textural qualities. The
products were very light in weight with 0.19-0.27 g/cm.sup.3 piece
density and expanded well with an expansion ratio of 7.7-8.4.
TABLE-US-00004 TABLE 4 Textural characteristics of apple pomace and
liquid-cheese whey incorporated extrudates and commercial sample
.sup.a Control- Apple Apple pomace Physical Starch pomace and
cheese Commer- characteristics extrudates extrudate .sup.b whey
extrudate .sup.c cial Jax .sup.d Piece density 0.21 b 0.29 a 0.27 a
0.17 c (g/cm.sup.3) Bulk density 0.14 b 0.22 a 0.24 a 0.12 b
(g/cm.sup.3) Expansion ratio 10.7 a 8.6 b 8.5 b -- Hardness (N)
22.1 ab 20.8 b 25.2 a 12.2 c Crispiness 18.3 b 17.5 bc 15.8 bc 25.2
a (no. of peaks) Compressive 9.4 c 16.8 a 9.3 c 13.8 b modulus
(N/mm) .sup.a Means in the same row followed by the same letter are
not significantly different (p < 0.05). .sup.b Formulations
containing 22% apple pomace, 76% pregel starch, 1% lecithin, and 1%
distilled monoglycerides. .sup.c Formulations containing the above
formulation with added liquid whey at 5.1% on dry weight basis.
.sup.d Bachman Cheese Flavored Corn Snacks, Crunchy Jax Twists
TABLE-US-00005 TABLE 5 Physical characteristics of grape pomace and
liquid cheese-whey incorporated extrudates Control- Grape pomace
Physical Starch Grape pomace and cheese characteristics extrudates
extrudate .sup.b whey extrudate .sup.c Piece density 0.21 b 0.19 ab
0.23 a (g/cm.sup.3) Bulk density 0.14 ab 0.11 b 0.16 a (g/cm.sup.3)
Expansion ratio 10.7 a 8.4 b 7.7 c Hardness (N) 22.1 a 14.1 c 18.4
b Crispiness 18.3 a 16.5 b 12.6 c (number of peaks) Compressive 9.4
c 36.9 a 25.9 b modulus (N/mm) .sup.a Means in the same row
followed by the same letter are not significantly different (p <
0.05). .sup.b Formulations containing 22% apple pomace, 76% pregel
starch, 1% lecithin, and 1% distilled monoglycerides. .sup.b
Formulations containing the above formulation with added liquid
whey at 5.1% on dry weight basis.
[0110] When incorporating 22% pomace and 5% concentrated
cheese-whey by dry-weight in the fortified puffed extrudates,
certain textural qualities decreased compared to the control
starch-alone puffed product; expansion decreased from 10.7 to 8.6,
piece density increased from 0.21 to 0.27 g/cm.sup.3, bulk density
increased from 0.14 to 0.23 g/cm.sup.3 and hardness increased from
22.1 to 25.2 N (Table 4). The reduced textural qualities of the
pomace extrudates were due to reduced gas holding capacity of the
dough caused by the fiber in the pomace. As a result, the expansion
decreased and the piece density and hardness increased. A similar
trend was observed in grape pomace-incorporated products (Table
5).
[0111] When liquid cheese-whey was incorporated at 5.1% by dry
weight, the textural qualities of the apple pomace extrudates
remained same with and without added whey; however, certain
textural qualities decreased in grape pomace extrudates: expansion
degreased from 8.4 to 7.7, piece density increased from 0.19 to
0.23 g/cm.sup.3, bulk density increased from 0.11 to 0.16
g/cm.sup.3 and hardness increased from 14.1 to 18.4 N. However, all
puffed products fortified with fruit pomace and liquid whey were
very crispy and showed good overall textural characteristics. Both
of the SCFX processed products (pomace incorporated and cheese whey
fortified products) showed a comparable crispiness with control
product and the commercial product evaluated in this study (Tables
4 & 5). Typical commercial low-density puffed snakes prepared
by conventional steam extrusion have a density from 0.02-0.7 g/cm3.
Our pomace incorporated products are low in density and highly
expanded and thus provide crispy puffed products with good textural
qualities.
[0112] Internal Morphology.
[0113] Scanning electron microscope was used to evaluate the
internal morphology of the extruded products. The micrographs
presented in FIG. 8 confirmed that the puffed pomace products made
by SCFX process contained unique internal morphology with large
amounts of uniformly expanded air cell compared to the control
sample processed without supercritical CO.sub.2. Furthermore, the
products made from the present SCFX process produce extrudates with
more uniform internal cell structure compared to conventional steam
extrusion, which is due to the less forceful, controlled puffing
nature of SC--CO.sub.2 assisted extrusion. The unique internal cell
structure of the pomace products was an indicative of improved
textural and sensory attributes of the extrudates.
[0114] The average diameter of the internal air cell in the 22%
apple pomace puffs was 176.+-.57 .mu.m. The control puffs without
poamce contained a greater number of smaller air cells (128.+-.30
.mu.m, which were distributed uniformly throughout the extrudate
(FIG. 9). When the apple pomace was incorporated, the number of
opened cells increased, and number of air cell density decreased,
resulting in less expanded and collapsed internal structure.
However, the grape pomace extrudates showed appreciable porous
microstructure very similar to that of starch-alone extrudates. All
the SCFX processed expanded products have with unique internal
microstructure; the air cells were small in size (128-176 .mu.m)
and they were distributed uniformly throughout the products. On the
other hand most typical puffed products generated by conventional
steam expansion have large air cells (1-2 mm diameter) with less
uniform internal micro-structure.
[0115] An example utilization of apple and grape pomace in sweet
and savory extruded snacks is illustrated with the three modified
formulations listed in Table 6. The ingredient formulations were
modified in these products with the objective of further improving
the nutritional and sensory qualities of the pomace incorporated
extrudates. The extruder parameters and operating conditions used
in this process are summarized in Table 7. All other methods for
feed preparation, mixing, preconditioning, extrusion, product
shaping, and drying were performed as described previously in the
general methodology of the invention.
TABLE-US-00006 TABLE 6 Ingredient composition of flavored
apple-grape pomace extruded puffs Ingredient formulation for fruit
pomace extrudate (% w/w) Apple Pomace - Apple Pomace- Grape pomace-
Pie Puffs flavor Spicy Flavor Cheese flavor 22% Apple pomace 22%
Apple Pomace 22% Grape Pomace 48% Pregel cornstarch 56% Pregel 56%
Pregel cornstarch cornstarch 12% Soy protein isolate 10% Whey
Protein 10% Whey Protein Concentrate Concentrate 7% Brown Sugar 1%
Salt 1% Salt 7% Dried yogurt powder 1% Lecithin 1% Lecithin 1%
Lecithin 1% Dimodon 1% Dimodon 1% Diomodon 2% Maltodextrin 2%
Maltodextrin .8% Vanilla flavored extract 6.0% Spicy 1% Sour Cream
Seasoning .5% Natural Apple flavoring 1% Milk powder .6% Salt, .3%
Cinnamon 4.5% Cheese seasoning .4% Citric acid, .2% Nutmeg
TABLE-US-00007 TABLE 7 SCFX process parameters for flavored
apple-grape pomace extruded puffs Process conditions Apple Apple
Grape Pomace - Pomace- pomace- Pie Puffs Spicy Cheese Process
parameters flavor Flavor flavor Feed rate (kg/h) 35 35 35
Pre-conditioner speed 200 200 200 Water/steam flow in 0 0 0
pre-conditioner (%) Extruder motor 15 13 14 load (%) Extruder screw
100 100 120 speed (rpm) Water flow (% Feed) 22 22 22 Barrel
temperature 21-27 23-25 25-27 (.degree. C.) Die pressure (MPa) 11.7
11.7 10.3 SC-CO.sub.2 injection 7.6 .times. 10.sup.-5 7.6 .times.
10.sup.-5 7.6 .times. 10.sup.-5 rate (kg/s) SC-CO.sub.2 injection
7.6 7.6 7.6 pressure (MPa) Specific mechanical 54.2 47.7 61.5
energy (kJ/kg) Extrudate temperature 83.2 81 86 (.degree. C.)
[0116] The appearance of the representative extrudates produced by
SCFX is shown in FIG. 10. The puffed products showed good
appearance and color retention. The textural characteristics of the
pomace incorporated puffed products are given in Table 8. Although
certain textural qualities decreased compared to the control
starch-alone or starch-pomace base formulation products, the puffed
products showed good textural qualities. The bulk density
(0.30-0.35 g/cm.sup.3) and piece (0.23-0.27 g/cm.sup.3) density of
the products remained comparable with those of typical commercial
low-density puffed products (0.2-0.7 g/cm.sup.3).
TABLE-US-00008 TABLE 8 Physical characteristics of the flavored
apple-grape pomace extruded puffs and commercial sample .sup.a
Apple Apple Grape pomace - pomace - pomace - Physical Pie puffs
Spicy Cheese Commercial characteristics flavor flavor flavor Jax
.sup.b Piece density 0.35 0.30 0.34 0.17 (g/cm.sup.3) Bulk density
0.27 0.26 0.23 0.12 (g/cm.sup.3) Expansion ratio 6.8 7.0 6.1 --
Hardness (N) 28.0 30.4 27.3 12.2 Crispiness 14.1 10.6 12.1 25.2
(no. of peaks) Compressive 13.1 13.6 16.7 13.8 modulus (N/mm)
.sup.a Means in the same row followed by the same letter are not
significantly different (p < 0.05). .sup.d Bachman Cheese
Flavored Corn Snacks, Crunchy Jax Twists
[0117] Table 9 shows that nutrient content of the apple pomace
incorporated products obtained in this present invention had
significantly better nutritional profile compared to the commercial
products. Specifically, dietary fiber and protein contents improved
compared to the control products. Total protein content of the
product improved from 1.5 to 12.1% and the total dietary fiber
content also improved from 14.2 to 16.5 g/100-g product compared to
the base apple pomace product. Furthermore, the pomace incorporated
products contained good amount of phenolics in the final product
(80 mg/100 g product); whereas, the commercial product contained
negligible amounts of dietary fiber and phytochemical. These
example formulations demonstrated that the fruit pomace can be used
in the production of cereal based puffed products with added
nutrients and functional ingredients. The naturally colored,
nutrient enriched products are ideal for ready-to-eat functional
food such as breakfast cereals and snacks.
TABLE-US-00009 TABLE 9 Estimated nutrient composition of flavored
apple pomace extruded puffs and commercial sample .sup.a Apple
pomace Apple Pomace - Commercial extrudate Pie Puffs flavor Jax
(g/100 g (g/100 g (g/100 g Nutrients product) .sup.a product)
.sup.b product) Total dietary fiber 14.2 16.5 0.1 Protein 1.5 12.1
7.1 Fat 1.2 1.5 38.8 Carbohydrates 77.4 54.2 49.4 Soluble sugars
0.5 7.6 -- Minerals 0.3 0.9 -- Condensed Tannins 0.9 0.9 --
Polyphenolic 80 80 -- compounds (mg GAE/100 g DW) Antioxidant 280
280 -- capacity (ABTS) (mg VCE/100 g DW) Total calories 376.4 334.5
564.4 .sup.a Calculated based on ingredient composition on dry
weight basis .sup.b Formulations containing 22% apple pomace, 76%
pregel starch, 1% lecithin, and 1% distilled monoglycerides. .sup.b
Modified formulation listed in Table 6 .sup.d Bachman Cheese
Flavored Corn Snacks, Crunchy Jax Twists
[0118] By using supercritical fluid extrusion the present invention
demonstrates the effective utilization of the byproducts generated
from various food process operations as a source of health
enhancing dietary fiber and nutrients in low-density, puffed,
products while providing opportunities to local processors to
better transform their byproducts into value-added, edible
products.
Additional Embodiments of the Extruded Foodstuff of the Present
Disclosure
[0119] The following examples are intended to illustrate particular
embodiments of the present invention, but are by no means intended
to limit the scope of the present invention.
[0120] In various aspects, the present invention describes a
process for novel utilization of the byproducts (e.g., whey and
fruit pomce) generated during food and agro-processing operations
such as those manufactured in the yogurt, cheese, wine, and fruit
juice industries into puffed ready-to-eat extruded products without
compromising their nutritional qualities.
[0121] One embodiment of a procedure in accordance with the present
disclosure includes the following steps, attributes, or
formulations:
[0122] (a) Obtaining food grade pomace by removing inedible
portions such as seeds, stem from pomace. The pomace was dried in a
hot air oven at low temperature (40.degree. C. for 48 h) to
moisture content of 5-8%. The dried pomace was ground into fine
powder with a hammer mill to pass through a 0.031-0.048 inch
screen.
[0123] (b) Extrusion formulations consisting of 10-40% fruit pomace
by dry-weight and other required dry ingredients (50-76%
starch/flour/protein concentrate, 2% functional additives, <1%
flavoring ingredients)
[0124] (c) Concentrating liquid whey generated from dairy
processing operations (Greek yogurt, cheese manufacture) is to
.about.10-40% total solid content (%, dw) by using a
low-temperature vacuum evaporator.
[0125] (d) Adding concentrated liquid whey is directly into the
extruder barrel while processing the fruit pomace in the extruder
at a flow rate of 20-40% of the dry-feed flow rate, which will give
dough a water content of 18-32% and add 3-15% whey solids to the
feed formulation.
[0126] (e) Maintaining the extruder barrel temperature in the all 5
barrel zones at .about.25.degree. C. by circulating chilled brine
(-10.degree. C.) through barrel jackets. The product temperature at
the die-exit is .about.80-90.degree. C.
[0127] Injecting supercritical carbon dioxide (SC--CO.sub.2) as a
blowing (expansion) agent into the product melt at a constant flow
rate (7.6.times.10-5 kg/s) into the barrel through four valves
located at L/D of 24 at pressure of 1100 psi (7.58 MPa) (Rizvi et
al., 1995).
[0128] In certain embodiments, the process of the present
disclosure offers unique puffed products that are enriched in
dietary fiber and phytochemicals, as follows:
[0129] (a) Over 70% of the total polyphenols and 60% of the total
antioxidants of the fruit pomace are also preserved in the
extrudates.
[0130] (b) One version of 100 g of a product made by this process
contains 14 g dietary fiber, 93 mg phenolics, and 652 mg vitamin C
equivalent antioxidants.
[0131] (c) The extrudates are very light in weight with 0.19-0.27
g/cm.sup.3 piece density and expanded well with an expansion ratio
of 7.7-8.4, providing improved textural qualities.
[0132] (d) The expanded extrudates made in the present invention
have unique internal microstructure (uniform air cell distribution,
size, and density) compared to those made by steam extrusion.
Example 2
Supercritical CO.sub.2 Extrusion of Milk Protein Puffs Fortified
with Fruit Pomace and Liquid Cheese Whey
[0133] Fruit pomace and liquid cheese whey, byproducts generated
from food processing industries, were incorporated in high protein
extruded products as a source of dietary fiber and bioactive
nutrients. Feed formulations containing 70-90% milk protein
concentrate (MPC) with 22% fruit pomace were processed by
supercritical fluid extrusion (SCFX) at low-temperatures
(.about.90.degree. C.). The process incorporated concentrated
liquid cheese-whey containing 20.2 wt. % total solids by directly
injecting it into extruder barrel at 27.5 wt. % of the dry-feed
flow rate, providing 5.6% whey solids to the feed formulation. The
resulting MPC extrudates retained their creamy color and natural
fruit pomace color following SCFX processing, indicating that
little, if any, Maillard browning occurred during the process even
though a significant quantity of soluble sugars was present in both
the pomace and liquid whey. The addition of 22% fruit pomace and
5.6% (dry wt.) whey solids did not affect the piece density
(0.24-0.31 g/cm.sup.3), expansion ratio (4.6-5.7), and hardness
(38-78 N) of MPC extrudates, which were comparable to those of
starch- or protein-based extrudates made by conventional steam
extrusion. Incorporating fruit pomace in extruded products could
improve the dietary fiber and bioactive phytochemical contents of
the extrudates and the value of the byproducts as a source of
nutritional and functional food ingredients.
[0134] The objectives of this study were to evaluate the potential
of incorporating fruit pomace and concentrated liquid cheese-whey,
a byproduct of cheese making, in extrusion applications,
particularly in high protein extruded products comprised mainly of
milk protein concentrate by using low-temperature SCFX process and
determine their impact on end-product extrudate textural
qualities.
Materials and Methods
[0135] Apple pomace (AP) and grape pomace (GP) were obtained from
New York State Agricultural Experiment Station, Geneva, N.Y. The AP
and GP were dried at 40.degree. C. for 48 hours, and finely ground
with a hammer mill to pass through a screen size opening of 0.031
inches. The apple and grape pomace powders were stored in sealed
polyethylene bags at 4.degree. C. until used.
[0136] Milk protein concentrate (MPC) was purprovided by Glanbia
Nutritionals (Evanston, Ill., USA). Pre-gelatinized (pregel) corn
starch and Star-Dri_1, Maltodextrin were obtained from Tate &
Lyle Ingredients (Decatur, Ill., USA). Powdered lecithin was
provided by ADM-Lecithin (Decatur, Ill., USA). Distilled
mono-glyceride was provided by Danisco ingredients (Kansas, Mo.).
Acid cheese whey was obtained from the dairy processing pilot plant
at Cornell University, Ithaca, N.Y. and concentrated to a
.about.20% total solid content by using a vacuum evaporator at
temperature 70.degree. C. The pH of the concentrated whey was
4.2.
Feed Formulations
[0137] Experiment I was conducted to determine how fruit pomace
addition impacts the textural quality of protein and starch
extrudates. The MPC was pre-hydrated to 18% moisture by spraying
water while continuously mixing in a SP130 San Cassiano mixer
(Roddi Alba, Piemonte, Italy). In experiment II, the liquid cheese
whey was concentrated and directly injected into extruder barrel in
lieu of water and as a source of milk nutrients. The concentrated
liquid whey containing .about.20% solid content was injected at a
flow rate of 27.5 wt. % of the dry-feed flow, providing 5.6% dry
wt. whey solids to the final feed formulation. The feed
formulations and functionalities of each ingredient used in these
experiments are shown in Table 10 and Table 11.
TABLE-US-00010 TABLE 10 Feed formulations used for fruit pomace
extrusion Milk Protein Extrudate Concentrate- Formulations 80 (%)
Binder/Starch (%) Fruit Pomace (%) MPC* 92 6% Maltodextrin No
Apple/grape pomace MPC + AP 70 6% Maltodextrin 22% Apple pomace MPC
+ GP 70 6% Maltodextrin 22% Grape pomace Starch 0 98% Pregel Starch
No Apple/grape pomace Starch + AP 0 76% Pregel Starch 22% Apple
pomace Starch + GP 0 76% Pregel Starch 22% Grape pomace MPC: Milk
Protein Concentrate-80; AP: apple pomace, GP: grape pomace. All 5
formulations contained 1% distilled monoglycerides and 1% lecithin
as emulsifier and anti-sticking agents, respectively. *MPC was
pre-hydrated to 18% moisture by spraying water while continuously
mixing in a SP130 San Cassiano mixer (Roddi d'Alba, Piemonte,
Italy).
TABLE-US-00011 TABLE 11 SCFX process parameters for pomace
incorporated milk protein extrudates Process conditions Process
parameters MPC alone MPC + AP MPC + GP Feed rate (kg/h) 35 35 35
Extruder motor load (%) 15 13 14 Extruder screw speed (rpm) 180 135
180 Water/liquid whey flow 40 25 22.5 (% Feed) Specific mechanical
73.2 52.5 61.5 energy (kJ/kg) Extrudate temperature 92 85.3 99
(.degree. C.)
All other constant parameters: Barrel temperature=25.degree. C.;
Die pressure=10.3 MPa; SC--CO.sub.2 injection pressure=7.6 MPa;
SC--CO.sub.2 injection rate=7.6.times.10.sup.-5 kg/s to provide 1%
of the feed rate.
Supercritical-CO.sub.2 Extrusion
[0138] Dry blend formulations were extruded using a pilot scale
Wenger TX-52 co-rotating twin-screw extruder with barrel diameter
of 52 mm and length/diameter (L/D) ratio of 28.5 configured to
operate at a screw speed of 100-180 rpm and the die pressure of
1200 psi (FIG. 11, Wenger Manufacturing, Sabetha, Kans.). The feed
rate was set to 35 kg/h for all treatments, with injection of 1%
supercritical CO.sub.2 of dry feed flow. Water was injected into
the extruder at 22-24 wt. % of dry feed flow rate. The final
product temperature was around 86-94.degree. C. A circular
cross-section die with diameter of 4.13 mm were used to shape the
extrudates. The extrudates were cut into ball shaped products using
a knife with 2 blades rotating at 900 rpm, collected in trays, and
dried in a forced-air oven at 90.degree. C. to .about.5-8% moisture
content. The products were allowed to cool down to room temperature
and stored in sealed bags.
[0139] The specific mechanical energy (SME) input into the dough
was calculated from the following equation:
SME = 37.3 ( % Extruder load 100 ) ( Extruder screw speed 306 ) (
3600 Extruder feed rate ) ( 1 ) ##EQU00001##
[0140] where extruder screw speed is in rpm (100-180 rpm), 306 rpm
is the maximum extruder screw speed, 37.3 kW is the power input and
the extruder feed rate is in kg/h (35 kg/h)
Extrudate Characterization
[0141] Bulk density was measured by filling a container of known
volume with the product, and dividing the weight of extrudates by
its volume. Piece density, defined as the ratio of the mass of the
sample to that of its volume that includes internal pores but
excludes the void or space among the pieces, was measured by using
sand displacement method (Webb 2001). Five replicates were measured
for each set of samples. Expansion ratio was calculated as the
cross-sectional area of the extrudate divided by the
cross-sectional area of the die opening (Alavi et al. 1999). An
average diameter of 10 samples was measured with a Vernier caliper
to determine the expansion ratio of each set of samples.
[0142] The color of extrudates was measured with a CR-400 Chroma
Meter (Konica Minolta Sensing Inc., Osaka, Japan) using the CIE L*,
a*, b* coordinate system. The color meter was calibrated with a
standard white plate (Y=93.8, x=0.3131, y=0.3191). Extrudates were
ground into fine powder and the color readings were taken with five
replicates of each sample. The total color difference (DE) and
browning index (BI, purity of brown color) of the premix blends and
extruded products were calculated using the following
equations:
DL*=L*.sub.1-L*.sub.2,Da*=a*.sub.1-a*.sub.2, and
Db*=b*.sub.1-b*.sub.2 (2)
Where L*.sub.1, a*.sub.1, b*.sub.1 mean color values of the initial
blend before extrusion, and L*.sub.2, a*.sub.2, b*.sub.2 represent
color values of the final products after extrusion.
DE = DL * 2 + Da * 2 + Db * 2 ( 3 ) BI = 100 ( x - 0.31 ) 0.17
where x = a 2 * + 1.75 L 2 * 5.645 L 2 * + a 2 * - 3.012 b 2 * ( 4
) ##EQU00002##
[0143] Textural characteristics of the extrudates were determined
by using a TA-XT2 texture analyzer operating with Texture Exponent
32 software (both from Stable Micro Systems Ltd., Godalming,
Surrey, U.K.). Fifteen extrudates from each treatment were
equilibrated using a humidity chamber (28% RH, 48 h). The
extrudates were compressed perpendicular to the direction of
extrusion to 50% of their average original diameter, using a 35 mm
compression plate at a test speed of 2 mm/s. The peak force (N),
initial gradient (N/mm) and the total number of peaks of the
force-deformation curve were recorded and analyzed to calculate the
hardness, compression modulus, and crispiness of the products,
respectively (Stojceska et al. 2008; Bruns and Burne 1975).
[0144] Moisture content of samples was determined by drying samples
in a forced air oven at 130.degree. C. for 2 hours. Water activity
was measured using the AquaLab water activity meter (Decagon
Device, Inc., Pullman, Wash., USA). Water hydration capacity (CH)
of the ingredients and premix formulations were determined by using
the AACC method 56-20 (AACC international, 2009; Karkle et al.,
2012). The CH was defined as grams of water adsorbed per grams of
dry matter. A 75 mg sample was weighed into 1.5 mL centrifuge tubes
and 1-mL distilled water was added and tubes were vortexed to
suspend the contents. The material was allowed to hydrate for 10
min with vortexing in 5 and 10 min. The tubes were centrifuged for
15 min using Eppendorf 5414 Centrifuge (Hamburg, Germany). The
supernatant was discarded and the sediment was weighed to estimate
the grams of water adsorbed per grams of dry matter.
[0145] The internal microstructure of the pomace extrudates were
observed by Tescan-Mira FESEM electron microscope. The sample was
cut into a thin slice, mounted on aluminum stubs with double-sided
adhesive tape, coated with gold-palladium, and examined at an
intensity of 5 kV.
Statistical Analysis
[0146] Twelve treatments of varying composition of protein and
starch-based apple and grape pomace formulations were extruded with
water (control) and concentrated liquid cheese whey with two
replications. Data were analyzed for analysis of variance by using
JMP 10.0.2 statistical software (SAS Institute Inc.). Least
significant differences were determined using Tukey-Kramer HSD test
at the 5% significance level.
Result and Discussion
Effect of Fruit Pomace Incorporation
[0147] Photographs of representative MPC and starch-based fruit
pomace extrudates are shown in FIG. 12. The MPC extrudates without
added pomace retained its creamy color after SCFX process,
indicating that little, if any, Maillard browning occurred during
the process. Extrudates containing apple and grape pomace retained
the distinctive color of their respective fruit. Since the process
uses low temperature and low sheer conditions, it did not cause any
discoloration to the final products, indicating the retention of
protein nutritional qualities of the final extrudates.
[0148] Extrudate physical properties including bulk density, piece
density, and expansion ratio are summarized in Table 12. The
MPC-fruit pomace extrudates showed higher density and lower
expansion ratio compared to starch-based pomace extrudates. Allen
et al. (2007) reported that high amount of protein inhibits the
growth of air cells in extrudates, which results protein extrudate
with low expansion and high density. However, the MPC-based
extrudates made in this study with supercritical fluid extrusion
had piece densities ranging from 0.24 to 0.29 g/cm.sup.3, which
were lower than those reported for various protein extrudates: whey
protein extrudate containing 50-70% whey protein concentrate had
piece density of 0.63-0.75 g/cm.sup.3 (Paraman et al. 2013) and soy
protein extrudates containing 50% soy protein concentrate had
density of 0.30-0.45 g/cm.sup.3 (Zhu et al. 2010). Extruded food
products that have density in the range of 0.02-0.7 g/cm.sup.3 are
classified as low density products thereby the present MPC-pomace
extrudates made by SCFX can be classified as low-density, expanded
products.
TABLE-US-00012 TABLE 12 Selected physical properties of MPC- and
starch-based fruit pomace extrudates .sup.1 Bulk Piece Compression
Crispness density density Expansion Hardness modulus (No. of
Treatments (g/cm.sup.3) (g/cm.sup.3) ratio (N) (N/mm) peaks)
Protein-based extrudates MPC 0.21 a 0.29 a 5.6 c 61.6 a 80.7 ab
14.0 a MPC + AP 0.22 a 0.29 a 5.4 c 39.3 b 94.1 a 12.5 b MPC + GP
0.22 a 0.24 b 5.7 c 38.6 c 54.3 bc 15.1 a Starch-based extrudates
Starch 0.14 c 0.21 b 10.7 a 22.1 c 9.4 d 18.3 a Starch + AP 0.18 b
0.23 b 8.2 b 22.2 c 26.3 c 17.5 a Starch + GP 0.13 c 0.18 c 10.6 a
19.1 d 16.2 c 16.7 a .sup.1 Means in the same column followed by
different letters are significantly different (P < 0.05). MPC:
milk protein concentrate; AP: apple pomace; GP: grape pomace.
[0149] When added up to the 22% level, the apple or grape pomace
did not affect the expansion or density of the final MPC
extrudates. However, when the same level of the fruit pomace were
added to starch-based formulations, the expansion ratio decreased
from 10.7 to 8.2, piece density increased from 0.21 to 0.24
g/cm.sup.3, and bulk density increased from 0.14 to 0.18
g/cm.sup.3. Previous studies also indicated that the addition of
pomace decreased the expansion of extrudate and thus increased the
density of the final products due to the high content of insoluble
fiber of pomace, which reduces viscoelasticity and gas holding
capacity of the extrudate melt (Lue, et al. 1990). As previously
reported by other researchers, the starch-based pomace extrudates
showed an inverse relationship between density and expansion
(Koksel et al. 2003; Karkle et al. 2012).
[0150] Hardness, brittleness, and crispiness of the pomace
extrudates are summarized in Table 12. Compared to starch-based
extrudates, the MPC-pomace extrudates showed higher hardness and
brittleness. As expected, the hardness values inversely correlated
with the expansion ratio of extrudates. According to Maskan and
Altan (2011), the extrudates that had a lower expansion had thicker
cell wall and thus higher hardness. The addition of fruit pomace
decreased the hardness of MPC extrudates, which was probably caused
by the insoluble fiber of the pomace, however, the pomace addition
did not affect the hardness of the starch-based extrudates. Overall
the hardness values of MPC-based extrudates (39-62 N) and
starch-based extrudates (19-22 N) made by the present SCFX process
were comparable to those reported for corn flour-based apple pomace
extrudates made by conventional steam extrusion (20-70 N) (Karkle
et al. 2012). Similarly, the crispiness measured by number of peaks
of force deformation curve indicated that crispiness of the pomace
incorporated extrudates were comparable to that of their respective
starch-alone or protein-alone control extrudates.
[0151] The pomace addition did not much affect the hardness or
crispiness, which contradicted to the typical inverse relationship
between expansion ratio and hardness reported in the literature.
The pomace incorporated extrudates might be more brittle as
compared to those of starch or MPC alone extrudates due to high
content of fiber derived from pomace. Besides, as indicated in
Table 11, the optimal feed moisture requirement decreased from 35%
to 22.5 when pomace was incorporated in starch or protein-alone
formulations, which was due to the high hydration capacity of
pre-gelatinized starch (13.6 g water/g starch) and MPC (7.3 g
water/g MPC) as compared to pomace incorporated formulations
(3.0-4.8 g water/g formulation) (data not listed in Table).
Compared to starch or MPC-alone control formulation, pomace
incorporated formulations required less water requirement (22-25%
of the feed flow rate) during the processing. Because of its high
fiber content, the fruit pomace incorporation significantly
decreased the water hydration capacity of the formulations (3.0-4.8
g water/g formulation). The decreased in the in-barrel moisture
might have compensated the increased hardness caused by pomace
addition.
Effect of Liquid Cheese-Whey Incorporation
[0152] Liquid cheese whey, a by-product of cheese manufacturing,
was added to extrudate as a source of milk nutrients. The liquid
whey was concentrated to 20.2% total solid content and directly
injected into the extruder barrel at 27.5 wt. % of dry-feed flow
rate. Photographs of the MPC extrudates fortified with fruit pomace
and liquid whey are shown in FIG. 13. As seen in the photograph of
the protein puffs, there were no undesirable color change caused by
liquid whey addition, indicating that no any undesirable
interaction between protein and soluble sugars occurred during the
process, even though a significant quantity of soluble sugars were
present in both pomace and liquid whey.
[0153] No significant differences were observed in water activity
of the pomace extrudates extruded with water or whey although the
extrudates made with whey contained higher moisture contents than
those made with water, which was due to the high hygroscopic nature
of lactose presence in whey (Table 13). Whey solids are known to
bind water and increase the moisture retention of the final
extrudates (Onwulata et al. 1998). All the pomace extrudates had
low water activity (0.49-0.54) and thus they are shelf-stable
products. According to Grant (2004), a water activity of 0.61 is
the lowest value for microbial growth.
[0154] Selected physical properties of liquid cheese whey added
extrudates are shown in Table 13. The piece density and expansion
ratio of pomace extrudates extruded with water or whey did not
differ significantly. Previous studies indicated that with the
addition of whey protein and lactose, the expansion ratio of
extrudate is generally reduced (Onwulata et al. 1998 & 2001).
However, no such differences were observed in expansion ratio and
piece density of the extrudates made with water and liquid whey in
this study, which probably be due to the fact that liquid whey
provided only 5.6% (dry wt.) whey solids. The hardness values of
the liquid whey-added products were higher than those of the
control water-added products, which might be due to the protein and
lactose presence in liquid whey. As indicated by the compression
modulus values, the MPC-pomace extrudates made with liquid whey had
lower brittleness than the extrudates made with water. The
crispiness of both water and whey added extrudates were not
significantly different. Overall, the liquid cheese whey addition
did not affect the textural qualities of the apple or grape pomace
extrudates.
TABLE-US-00013 TABLE 13 Textural properties of MPC-fruit pomace
extrudates made with water and liquid whey.sup.1 Physical Extruded
with water (control) Extruded with liquid whey characteristics MPC
MPC + AP MPC + GP MPC MPC + AP MPC + GP Moisture content (%) 9.3 b
8.1 b 7.2 b 11.5 a 8.8 ab 8.1 ab Water activity (a.sub.w) 0.52 a
0.54 a 0.50 a 0.53 a 0.52 a 0.51 a Bulk density (g/cm.sup.3) 0.21 a
0.22 a 0.22 a 0.24 a 0.24 a 0.20 a Piece density (g/cm.sup.3) 0.29
a 0.29 a 0.24 b 0.30 a 0.31 a 0.24 b Expansion ratio 5.6 b 5.4 ab
5.7 a 5.7 ab 4.6 b 5.6 ab Hardness (N) 61.6 a 39.3 b 38.6 b 63.7 ab
77.8 a 52.4 bc Compression modulus (N/mm) 80.7 b 94.1 a 54.3 bc
90.0 ab 42.8 cd 37.8 d Crispness (No. of peaks) 14.0 abc 12.5 c
15.1 abc 12.8 bc 16.4 ab 16.9 a .sup.1Means in the same column
followed by different letters are significantly different (P <
0.05). MPC: milk protein concentrate; AP: apple pomace; GP: grape
pomace.
[0155] SEM pictures confirmed that MPC extrudates had air cell with
thicker cell wall (13.7.+-.3.1 .mu.m) compared to starch extrudates
(6.8.+-.1.5 .mu.m) (FIG. 14). This explains the textural quality
differences observed between MPC and starch based pomace
extrudates. However, the both pomace extrudates of MPC and starch
made by SCFX process contained unique uniform internal morphology
with closed cell structure. Furthermore, no significant differences
were observed with the internal morphology due to whey or water
added extrudates (micrograph not shown).
[0156] As seen in Table 14, addition of fruit pomace increased the
natural color of the extrudates. The liquid whey addition did not
affect the color of the final products, even though a significant
quantity of soluble sugars was present in both pomace and liquid
whey. Apple pomace contains phenolic compound, phloridzin, which
produces yellow compounds due to oxidation so that b* value after
extrusion was distinctly increased from 14.6 to 26 compared to the
initial blend (Bhushan et al. 2008). As reported by Maskan and
Altan (2011) pomace incorporation reduced the lightness (L* value)
and increased the redness (a* value) of the extrudates, mostly due
to the natural color of the original pomace. The browning index
(BI) indicates the purity of brown color which is an index of
enzymatic and non-enzymatic reactions (Palou et al. 1999). The BI
value was not significantly changed by liquid whey addition to all
six formulations. However, addition of apple pomace showed larger
change in BI values of the final extrudates whereas the grape
pomace extrudates showed comparatively smaller change in BI values
before and after extrusion, indicating the influence of the natural
color of pomace rather than the color change due to browning
reactions.
TABLE-US-00014 TABLE 14 Color analysis of MPC-pomace extrudates
made with water and liquid whey.sup.1 Color Dry blend premix
Extrudates change Treatments L.sub.0 a.sub.0 b.sub.0 BI.sub.0
L.sub.E a.sub.E b.sub.E BI.sub.E (DE) Extruded with water (control)
MPC 98.2 a -1.72 c 11.2 b 10.5 b 87.4 b -1.32 d 25.1 a 32.0 b 17.6
d MPC + AP 89.5 b 1.62 b 14.5 a 18.6 a 73.0 c 7.34 a 26.5 a 51.6 a
21.1 b MPC + GP 80.8 c 1.98 a 6.44 c 9.9 c 55.6 d 4.99 c 6.6 c 18.8
d 25.3 a Extruded with liquid whey MPC 98.2 a -1.72 c 11.2 b 10.5 b
90.9 a -1.98 e 21.3 b 24.5 c 12.5 e MPC + AP 89.5 b 1.62 b 14.5 a
18.6 a 74.5 c 6.29 b 26.0 a 48.4 a 19.5 c MPC + GP 80.8 c 1.98 a
6.44 c 9.9 c 56.3 d 4.65 c 4.8 c 14.7 d 24.7 a .sup.1Means in the
same column followed by different letters are significantly
different (P < 0.05). MPC: milk protein concentrate; AP: apple
pomace; GP: grape pomace; DE: total color difference of samples
before and after extrusion; BI: browning index.
CONCLUSIONS
[0157] Fruit pomace and liquid whey were incorporated into protein
and starch based ready-to-eat extruded products by using a
low-temperature (.about.90.degree. C., melt temperature), low-shear
(100-180 rpm) supercritical fluid extrusion process. The addition
of pomace (22% wt.) and liquid whey containing whey solids of 5.6%
wt. did not affect the overall textural quality of the final
extrudates. The protein (MPC-based) extrudates had piece density of
0.24-0.31 g/cm.sup.3, which was within the range of protein
extrudates made by conventional steam extrusion (0.02-0.7
g/cm.sup.3). Hardness of the pomace and liquid whey incorporated
MPC extrudates ranged from 38-78 N, which was higher than those of
starch-based pomace extrudates (22-38 N). However, the hardness
values of the MPC-pomace extrudates were comparable to those of the
protein extrudates (20-70 N) made by steam extrusion. The fruit
pomace addition can improve the dietary fiber contents of the
protein extrudates without compromising their end-product textural
qualities.
REFERENCES
[0158] Citation of a reference herein shall not be construed as an
admission that such reference is prior art to the present
invention. All references cited herein are hereby incorporated by
reference in their entirety. Below is a listing of various
references cited herein: [0159] AACC International, 2000. Approved
Methods of the American Association of Cereal Chemists, 10th Ed.
Methods 44-31. The Association: St. Paul, Minn. [0160] Alavi, S.
H., Gogoi, B. K., Khan, M., Bowman, B. J. & Rizvi, S. S. H.
(1999). Structural properties of protein-stabilized starch-based
supercritical fluid extrudates. Food Research International, 32,
107-118. [0161] Alavi, S., & Rizvi, S. S. H. Supercritical
fluid extrusion--a novel method for producing microcellular
structures in starch-based matrices. In Novel Food
Processing--Effects on Rheological and Functional Properties, Eds.
Ahmed, J., Ramaswamy, H. S., Kasapis, S., and Boye, J. Taylor and
Francis. 2009. pp [0162] Alavi, S., Karkle, E., Adhikari, K., &
Keller, L. (2011). Extrusion research for addressing the obesity
challenge. Cereal foods world, 56(2), 56-60. [0163] Allen, K. E.,
Carpenter, C. E., & Walsh, M. K. (2007). Influence of protein
level and starch type on an extrusion-expanded whey product.
International Journal of Food Science and Technology, 42, 953-960.
[0164] Altan, A., McCarthy, K. L., & Maskan, M. (2008a).
Evaluation of snack foods from barley-tomato pomace blends by
extrusion processing. Journal of Food Engineering, 84(2), 231-242.
[0165] Altan, A., McCarthy, K. L., & Maskan, M. (2008b).
Twin-screw extrusion of barley-grape pomace blends: Extrudate
characteristics and determination of optimum processing conditions.
Journal of Food Engineering, 89(1), 24-32. [0166] Ar as, J. A.
(1992). Extrusion of Food proteins. Critical reviews in food
science and nutrition, 32(4), 365-92. [0167] Balasundram, N.,
Sundram, K., & Samman, S. (2006). Phenolic compounds in plants
and agri-industrial by-products: Antioxidant activity, occurrence,
and potential uses. Food Chemistry, 99(1), 191-203. [0168] Bhushan,
S., Kalia, K., Sharma, M., Singh, B., & Ahuja, P. S. (2008).
Processing of apple pomace for bioactive molecules. Critical
reviews in biotechnology, 28(4), 285-96. [0169] Bibbins-Martineza,
M. D., Enciso-Chavez, B., Galiciaa, S. B. N., & Hernandez. D.
C. Soluble Dietary Fiber generation from Apple Pomace
http://www.icef11.org/content/papers/few/FEW1013.pdf [0170]
Brennan, M. A., Derbyshire, E., Tiwari, B. K., & Brennan, C. S.
(2013). Ready-to-eat snack products: the role of extrusion
technology in developing consumer acceptable and nutritious snacks.
International Journal of Food Science & Technology. [0171]
Brunner, G. (2005). Supercritical fluids: technology and
application to food processing. Journal of food engineering,
67(1-2), 21-33. [0172] Bruns, J. A., & Bourne, M. C. (1975).
Effects of sample dimensions on the snapping force of crisps foods.
Journal of Texture Studies, 6, 445-458. [0173] Cho, K. Y. &
Rizvi, S. S. H. (2010). New generation of healthy snack food by
supercritical fluid extrusion. Journal of Food Processing and
Preservation, 34, 192-218. [0174] Deng, Q., Penner, M. H., &
Zhao, Y. (2011). Chemical composition of dietary fiber and
polyphenols of five different varieties of wine grape pomace skins.
Food Research International, 44 (9) (2011), pp. 2711-2719. [0175]
Gassara, Fatma, Brar, S. K., Pelletier, F., Verma, M., Godbout, S.,
& Tyagi, R. D. (2011). Pomace waste management scenarios in
Quebec--Impact on greenhouse gas emissions. Journal of Hazardous
Materials, 192(3), 1178-1185. [0176] Grant, W. D. (2004). Life at
low water activity. Philosophical Transactions of the Royal Society
B: Biological Sciences, 359(1448), 1249-1267. [0177] Harper, J. M.
(1981). Extrusion of Foods, Vol. 1. Pp. 21-45. Boca Raton: CRC
press, Inc. [0178] Hwang, J. K., Choi, J. S., Kim, C. J., &
Kim, C. T. (1998). Solubilization of Apple Pomace by Extrusion.
Journal of Food Processing and Preservation, 22(6), 477-491. [0179]
Karkle, E. L., Alavi, S., & Dogan, H. (2012). Cellular
architecture and its relationship with mechanical properties in
expanded extrudates containing apple pomace. Food research
international, 46(1), 10-21. [0180] Khanal R C, Howard L R,
Brownmiller C, Prior R L (2009a) Influence of extrusion processing
on procyanidin composition and total anthocyanin contents of
blueberry pomace. Journal of Food Science 74:52-58. [0181] Khanal,
R. C., Howard, L. R., & Prior, R. L. (2009b). Procyanidin
Content of Grape Seed and Pomace, and Total Anthocyanin Content of
Grape Pomace as Affected by Extrusion Processing. Journal of Food
Science, 74(6), H174-H182. [0182] Koksel, H., Ryu, G. H.,
Ozboy-Ozbas, O., Basman, A. & Ng, P. K. W. (2003). Development
of a bulgur-like product using extrusion cooking. Journal of the
science of food and agriculture, 83, 630-636. [0183] Lue, S.,
Hsieh, F., Peng, I. C. & Huff, H. E. (1990). Expansion of corn
extrudates containing dietary fiber: A microstructure study.
Lebens-Wiss Technol, 23, 165-173. [0184] Madrera, R. R., Bedrinana,
R. P., Hevia, A. G., Arce, M. B., & Valles, B. S. (2013).
Production of spirits from dry apple pomace and selected yeasts.
Food and Bioproducts Processing. [0185] Mahawar, M., Singh, A.,
& Jalgaonkar, K. (2012). Utility of apple pomace as a substrate
for various products: A review. Food and Bioproducts Processing, 90
(4), 597-605. [0186] Maskan M., & Altan A. (2011). Advances in
Food Extrusion Technology. CRC Press 2011. 121-168. [0187] Masoodi,
F. A., Sharma, B., & Chauhan, G. S. (2002). Use of apple pomace
as a source of dietary fiber in cakes. Plant Foods for Human
Nutrition, 57(2), 121-128. [0188] Min, S., Evrendilek, G. A., &
Zhang, H. Q. (2007). Pulsed electric fields: processing system,
microbial and enzyme inhibition, and shelf life extension of foods.
IEEE Transactions on Plasma Science, 35(1), 59-73. [0189] Onwulata,
C. I., & Heymann, H. (1994). Sensory properties of extruded
corn meal related to the spatial distribution of process
conditions. Journal of sensory studies, 9(1), 101-112. [0190]
Onwulata, C. I., Konstance, R. P., Smith P. W., & Holsinger, V.
H. (1998). Physical properties of extruded products as affected by
cheese whey. Journal of food science: an official publication of
the Institute of Food Technologists, 63(5), 814. [0191] Onwulata,
C. I., Smith, P. W., Konstance, R. P., & Holsinger, V. H.
(2001). Incorporation of whey products in extruded corn, potato or
rice snacks. Food Research International, 34(8), 679-687. [0192]
Palou, E., Lopez-Malo, A., Barbosa-Canovas, G. V., Welti-Chanes,
J., & Swanson, B. G. (1999). Polyphenoloxidase activity and
color of blanched and high hydrostatic pressure treated banana
puree. Journal of Food Science, 64(1), 42-45. [0193] Paraman, I.,
Supriyadi, S., Wagner, M. E., & Rizvi, S. S. (2013). Prebiotic
fiber-incorporated whey protein crisps processed by supercritical
fluid extrusion. International Journal of Food Science &
Technology. DOI: 10.1111/ijfs.12204. [0194] Paraman, I., Wagner, M.
E., & Rizvi, S. H. (2012). Micronutrient and protein fortified
whole grain puffed rice made by supercritical fluid extrusion.
Journal of Agricultural and Food Chemistry 60: 11188-11194. [0195]
Rizvi, S. S. H.; Mulvaney, S. J. Extrusion Processing with
Supercritical Fluids. U.S. Pat. No. 5,120,559. 1992. [0196] Rizvi,
S. S. H.; Mulvaney, S. J.; Sokhey, A. S. The combined application
of supercritical fluid and extrusion technology. Trends Food Sci.
and Technol. 1995, 6, 232-240 [0197] Robinson, T. Chandran, B.
Nigam, P. Removal of dyes from a synthetic textile dye effluent by
biosorption on apple pomace and wheat straw. Water Research, 36
(2002), pp. 2824-2830 [0198] Schieber, Andreas, et al., "A new
process for the combined recovery of pectin and phenolic compounds
from apple pomace." Innovative Food Science & Emerging
Technologies 4.1 (2003): 99-107. [0199] Stojceska V., Ainsworth P.,
Plunkett A., Ibanoglu E., & Ibanoglu S. (2008). Cauliflower
by-products as a new source of dietary fibre, antioxidants and
proteins in cereal based ready-to-eat expanded snacks. Journal of
Food Engineering, 87 (4), 554-563. [0200] Vendruscolo, F.,
Albuquerque, P. M., Streit, F., Esposito, E., & Ninow, J. L.
(2008). Apple pomace: A versatile substrate for biotechnological
applications. Critical Reviews in Biotechnology, 28(1), 1-12.
[0201] Walsh, M. K., & Wood, A. M. (2010). Properties of
Extrusion-Expanded Whey Protein Products Containing Fiber.
International Journal of Food Properties, 13 (4), 702-712. [0202]
Wang, H. J. Thomas R. L. (1989). Direct Use of Apple Pomace in
Bakery Products. Journal of Food Science, 54 (1989), pp. 618-620 3
[0203] Webb, P. 2001. Volume and density determinations for
particle technologists. Micromeritics Instrument Corp. Available
from: www.micromeritics.com. [0204] White B L, Howard L R, Prior R
L (2010) Release of bound procyanidins from cranberry pomace by
alkaline hydrolysis. Journal of Agricultural and Food Chemistry,
58:7572-7579 [0205] Yu, J., & Ahmedna, M. (2013). Functional
components of grape pomace: Their composition, biological
properties and potential applications. International Journal of
Food Science and Technology, 48(2), 221-237. [0206] Zhang, J.,
& Han, B. (2013). Supercritical or compressed CO.sub.2 as a
stimulus for tuning surfactant aggregations. Accounts of chemical
research, 46(2), 425-33.
[0207] Although preferred embodiments have been depicted and
described in detail herein, it will be apparent to those skilled in
the relevant art that various modifications, additions,
substitutions, and the like can be made without departing from the
spirit of the invention and these are therefore considered to be
within the scope of the invention as defined in the claims which
follow.
* * * * *
References