Note: Descriptions are shown in the official language in which they were submitted.
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IMPROVED BETA-GLUCAN AND METHODS OF USE
This application claims priority to U.S.
a
Provisional Application Serial No. 60/045,834, filed May
7, 1997, which is incorporated by reference herein.
FIELD OF THE INVENTION
This invention relates to the fields of food
processing and disease management through nutrition. In
particular, the invention provides an improved ~3-glucan
for use in food processing and health promotion through
nutritional supplementation.
BACKGROUND OF THE INVENTION
~3-glucan has been reported to have beneficial
therapeutic properties. It has been shown to lower both
total and LDL cholesterol while not reducing the
protective HDL cholesterol. It was found to help
maintain a normal glucose level in the blood of diabetic
patients, resulting in a decrease in insulin. It has
been found beneficial in the control of obesity. A
feeling of satiety is achieved from the residence time in
the lower intestine when ~i-glucan is included in the
diet. The ~i-glucan slows the rate of gastric emptying,
reduces the rate of carbohydrate absorption and it
absorbs and eliminates fats in the gut. Some
carbohydrates are also bound and eliminated and, thus are
not fully metabolized. ~3-glucan demonstrates good
functional properties as shown in various food product
developments. It has been shown to impart improvements
in "mouth feel" in products with reduced fat content. It
also retards staling in baked goods, thereby extending
shelf life by virtue of its ability to retain moisture
and also by virtue of its large molecular weight, which
slows water migration.
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(3-glucan obtained from conventional sources
possess, in varying degrees, the utility described above.
The main deficiency is the instability of conventional /3-
glucan to enzyme degradation. Thus, a need exists to
produce a (3-glucan of greater stability, thereby
improving its utility as a nutritional supplement and
food ingredient.
SUMMARY OF THE INVENTION
A /3-glucan having improved properties is
provided in accordance with the present invention. This
glucan preparation possesses a significantly higher
molecular weight and viscosity than (3-glucans prepared by
standard means. These properties enable the glucan to be
better resistant to enzymatic degradation, to exhibit a
longer residence time in the gastrointestinal tract and
thereby enhance the physiological functional properties
of conventional (3-glucan, and to extend the shelf life of
food products to which it is added.
According to one aspect of the invention, a
high molecular weight a-glucan is prepared by extrusion
of barley or oat flour. The (~-glucan has a viscosity
greater than about 1300 Braebender Units as measured in
the presence of accompanying starch in the extruded
material. It has a viscosity of greater than about 1100
cp as measured rheometrically after digestion of the
accompanying starch.
According to another aspect of the invention, a
method is provided for making ~i-glucan from barley or
oats, which comprises: (1) providing barley or oat flour,
preferably barley flour from waxy hull-less barley
varieties; and (2) extruding the flour under a die
temperature between about 100°C and 145°C, at a moisture
content of between about 20% and 50%.
According to another aspect of the invention, a
~i-glucan made by the above-described method is provided.
According to another aspect of the invention,
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the aforementioned improved (3-glucan is combined with one
or more other compositions to formulate a nutritional
supplement for health promotion or for control of a
disease condition, such as high cholesterol and/or blood
glucose.
According to another aspect of the invention,
the improved ~i-glucan is used as a food additive to
improve quality and shelf life of products. In preferred
embodiments it is used to replace part or all of the
glycerin that is currently used in the food products.
DETAINED DESCRIPTION OF THE INVENTION
The description below relates to the improved
(3-glucan of the invention and methods for producing it.
This ~i-glucan is useful for the control of certain
diseases, such as hypercholesteremia and diabetes. It
also has a variety of other uses, several of which are
set forth below, and others of which will be apparent to
one of skill in the art.
The improved /3-glucan of the invention is of
higher molecular weight and increased viscosity with
resultant greater resistance to enzyme degradation and
improved efficacy. The product is prepared by extrusion
of barley or oats, as described in greater detail below.
The enzyme degradation resistance and viscosity of the
product may be even further improved by coating the
product with a gum, such as a gum arabic.
(3-glucan can be obtained from oats or barley.
The barley variety preferred far use in the present
invention is a waxy variety, preferably a waxy hull-less
variety, such as Wanubet. However, ~i-glucan from any
barley or oat flour is expected to display some
= improvement in molecular weight and viscosity, if
prepared according to the methods of the present
invention.
In a particularly preferred embodiment of the
invention, a stabilized, fractionated barley flour
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available from Nu-Grain Products Co, (505 West North
Street, Harvey, North Dakota 58341), is used as the
starting material.
The ~i-glucan is prepared from the barley or oat
flour by extrusion under carefully controlled conditions.
Parameters, including die temperature and moisture, must
be balanced to produce an optimum product. Factors to be
considered include selecting moisture and die temperature
conditions sufficient to favor the formation of cross-
links, thereby increasing the molecular weight and
viscosity so as to impart the desired functionality of
the glucan, and the deactivation of (3-glucanase, but not
so great as to degrade the chain length of the ~i-glucan
or cook out the starch in the flour.
The mechanical pressure placed on the flour
during the extrusion process is a function of the
moisture content, die temperature and feed rate through
the extruder. The moisture level during the extrusion
process is kept in the range of 20-50%, preferably 25-40%
by weight. The die temperature is kept in the range of
100-145°C, preferably 110-135°C.
Examples 1-5 set forth particularly preferred
methods for preparing the improved ~i-glucan of the
invention. It will be appreciated by persons skilled in
the art that the aforementioned pressure, temperature and
moisture conditions are achieved by adjusting the
extruder to certain settings, which will vary from one
type of extruder to another. However, it is well within
the purview of the skilled artisan to adjust those
conditions to achieve the pressure, temperature and
moisture parameters set forth herein for production of
the ~3-glucan of the present invention.
Using the controlled conditions described
above, a high molecular weight ~3 glucan is prepared which
possesses a viscosity of between about 1300 and 1800
Braebender units in the presence of the accompanying
starch in the extruded material. As measured in
_._..~_.~.._.W..... ~ , , , ._ .
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centipoise, the viscosity is at least about 1100 cp, and
generally between about 1250 and 1690 cp after digestion
ofathe accompanying starch.
The improvements to viscosity and molecular
weight of the ~i-glucan described herein result in
improved efficacy aver ,Q-glucan provided by conventional
means. The higher molecular weight and viscosity of the
~3-glucan results in a longer residence time in the lower
digestive system. This improves its ability to lower
cholesterol and to maintain normal glucose levels in the
blood. This should also show benefits in weight
reduction by providing longer periods of satiety. The
improved resistance to enzyme degradation helps to
maintain these properties. The improved efficiency
. should also allow the ~3-glucan to be useful at lower
dosages when employed as food additive.
The improved ,Q-glucan has demonstrated superior
water retention properties. For instance, in meat
products, the product scored superior to other
commercially available starches and gums specifically
designed for meat applications. The superiority of the
(3-glucan of the invention in meat products is described
in greater detail in Example 6.
As additional examples, the same water
retention qualities makes the improved glucan very
effective in skin creams and has been demonstrated to
minimize wrinkles. Moreover, the product is expected to
exceed conventional products in extending shelf life and
delaying staling of baked goods.
The improve ~3-glucan of the invention is
especially useful in food products that presently use
glycerin in their formulations for the purpose of
reducing the percentage of water. Addition of glycerin
lowers the water activity of the product and its shelf
life is thereby extended. However, the negative result
of using glycerin is the poor taste and greasy mouthfeel
it imparts to the food product. Thus, while shelf life
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is_extended due to inhibition of microbial growth, the
overall quality of the product is less than desirable due
to the greasy quality and deterioration in flavor over
time, which accompanies glycerin-supplemented food
products.
The improved J3-glucan of the invention, with
its increased molecular weight, allows for as high as 50%
reduction of glycerin in a given food product, and
further serves to bind the remaining glycerin. This
prevents glycerin migration and lessens its reactivity
with other existing ingredients in the food.
The improved ;~-glucan can be used as-is,
providing great flexibility in sprinkling powder onto any
desired food or drink. Alternatively, it can be
developed into a dietary, supplemental confection as
pectin jellies or gum drops, a rather pleasant way to
intake a supplement. It can also be used as an
ingredient in extruded cereals, snacks, pasta, yogurt,
etc., and used to replace starch, gums or fats in a food
product.
The following examples are provided to describe
the invention in greater detail. They are not intended
to limit the invention in any way.
EXAMPLE 1
PREPARATION AND ANALYSIS OF IMPROVED Q-GLUCAN PSS-35-1
The starting material used to produce the
improved /3-glucan of the invention is a commercially
available (Nu-Grain Products Co.) waxy hull-less barley
flour, as described in the Detailed Description, that is
fractionated to give a higher content of ~3-glucan.
The product, referred to in this example as PSS
35-1, was prepared by extrusion, according to the
following protocol.
Extrusion Conditions
Screw speed = 150 rpm
Mass flow rate = 150 g/min
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Screw configuration = Pinto 1 (all forward
conveying elements) IGEL - 28/28 (6) - 28/14 (7) - 20/20
(6) - 20/10 (3) - 14/14 (6) (temperatures of zones 4 and
(see below) were basically the controlling variables
5 that determined the conditions used)
Moisture content = 30% (by weight)
Die temperature = 135°C
Die pressure = 170-19o psi
Torque = 12%
Barrel Temperature (zones 1-5 respectively, in
degrees Centigrade) - 168, 156, 78, 56, 24
Viscositv measurements 1 - Brookfield measurements:
Instrument used: Brookfield Model DV-I
Brookfield viscometer with #4 spindle and 5 and 10 rpm,
respectively.
Procedure of preparation: we prepared 5%
solutions of (1) "normal" barley flour, (2) fractionated
flour as described above (as a control) and (3) extruded
product PSS 35-1, in tap water. Samples were then heated
to 190°F and cooled to 160°F when viscosity measurements
were taken.
Findings:
Sample Viscositv
"normal" barley 248 cps
control 1220 cps
PSS 35-1 1890 cps
Viscosity measurements 2 - Hraebender measurements:
Instrument used: Braebender Visco/Amylo/Graph,
Model AVI S/N 577; cooling probe in "UP".
Procedure of preparation: Fractionated flour
("control") samples and PSS 35-1 samples were prepared by
mixing 35 g sample with 105 g granulated sugar and 360 g
distilled water, to a final weight of 500 g. Each sample
was mixed with the sugar and distilled water for about 1
min using a hand-held kitchen mixer, then placed into the
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instrument's sample bowl. Prepared samples were heated
to 30°C, held at that temperature for 60 minutes, at
which time the test was stopped and measurements made.
The 700 cmg sensitivity cartridge was used for
measurements in the instrument.
Findings:
Sample Viscosity
"control" 0 BU (Braebender Units)
PSS 35-1 beyond 1410 BU*
*the PSS 35-1 sample had not yet peaked in the 60 min
time frame.
Viscosity measurements 3 - spectrophotometric
measurements following removal of starch:
Instrument used: Rheometrics Fluids
Spectrometer, model 8400, using a cone and plate geometry
(diameter 5 cm, angle 0.1 radians). Each measurement was
taken for 2 minutes, and was initiated 7 and 8 minutes
after the starch digestion was completed.
Flour samples were milled on a Retch mill with
a 0.5 mM sieve. The powder was suspended in 150 ml of
lOmM sodium phosphate buffer, pH 6.9, and the temperature
adjusted to 37°C. Optionally, the sample was cooked
prior to starch digestion. For starch digestion, 8 mg
pancreatin (Sigma, P-1750) was added to the flour
suspension, and the suspension stirred for 1 hr at 37°C.
Findings:
Sample Viscosity
Control 866 cps
PSS-35-1 1470 cps
Molecular weight measurements
Comparative molecular weights of fractionated
flour ("control") and PSS 35-1 are as follows:
Sample Mol. Wt. (dad
Control 7.571 X 105
PSS 35-1 4.375 X 106
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EXAMPLE 2
PREPARATION AND ANALYSIS OF IMPROVED ~3-GLUCAN PSS 35 3
The product, referred to in this example as PSS
35-3, was prepared by extrusion, according to the
following protocol.
Starting Material and Extrusion Conditions
These were the same as for Example 1, with the
following exceptions:
Die temperature = 110-111°C
Die pressure = 210-230 psi
Torque = 13%
Barrel Temperature (zones 1-5 respectively, in
degrees Centigrade) - 122, 112, 68, 69, 25
Viscosity measurement - Braebender measurements:
Instrument used: Braebender Visco/Amylo/Graph,
Model AVI S/N 577; cooling probe in "UP".
Procedure of preparation: As described in
Example 1.
Findings:
Sample Viscosity
"control" 0 BU
PSS 35-3 1350 BU
EXAMPLE 3
PREPARATION AND ANALYSIS OF IMPROVED a-GLUCAN P88 35 4
The product, referred to in this example as PSS
35-4, was prepared by extrusion, according to the
following protocol.
Starting Material and Extrusion Conditions
These were the same as for Example 1, with the
following exceptions:
Die temperature = 120-121°C
Die pressure = 180=200 psi
Torque = 10-11%
Barrel Temperature (zones 1-5 respectively, in
degrees Centigrade) - 139, 130, 75, 40, 25
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Viscosity measurement - Braebender measurements:
Instrument used: Braebender Visco/Amylo/Graph,
Model AVI S/N 577; cooling probe in "UP".
Procedure of preparation: As described in
Example 1.
Findings:
Sample Viscosity
"control" 0 BU
PSS 35-4 1548 BU
EXAMPLE 4
PREPARATION AND ANALYSIS OF IMPROVED ~3-GLUCAN PSS-35-7
The product, referred to in this example a5 PSS
35-7, was prepared by extrusion, according to the
following protocol.
Startinq Material and Extrusion Conditions
These were the same as for Example 1, with the
following exceptions:
Moisture content = 470 (weight basis)
Die temperature = 120°C
Die pressure = 60-70 psi
Torque = 14%
Barrel Temperature (zones 1-5 respectively, in
degrees Centigrade) - 150, 136, 69, 27, 25
Viscosity measurement - Braebender measurements:
Instrument used: Braebender Visco/Amylo/Graph,
Model AVI S/N 577; cooling probe in "UP".
Procedure of preparation: As described in
Example 1.
Findings:
Sample Viscosity
"control" 0 BU
PSS 35-7 1710 BU
r
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_ EXAMPLE 5
PREPARATION AND ANALYSIS OF IMPROVED f3-GLUCAN PSS 35 8
The product, referred to in this example as PSS
35-8, was prepared by extrusion, according to the
following protocol.
Starting Material and Extrusion Conditions
These were the same as for Example 1, with the
following exceptions:
Moisture = 47% (by weight)
Die temperature = 128°C
Die pressure = 250-60 psi
Torque = 14%
Barrel Temperature (zones 1-5 respectively, in
degrees Centigrade) - 160, 136, 69, 27, 24
Viscosity measurement - Braebender measurements:
Instrument used: Braebender Visco/Amylo/Graph,
Model AVI S/N 577; cooling probe in "UP".
Procedure of preparation: As described in
Example 1.
Findings:
Sample Viscosity
"control" 0 BU
PSS 35-8 1650 BU
EXAMPLE 6
USE OF (3-GLUCAN IN MEAT PRODUCTS
This example illustrates the superiority of ~i-
glucan for use in meat products. Re-formed turkey
patties were formulated using the following ten products.
Each formulation was evaluated and rated for its
absorption qualities, texture and organoleptic qualities,
according to standard methods.
1) starch acetate flake
2) cellulose acetate micro fiber
3) cellulose acetate flake
4) Solka Floc
5) Viscarine #389
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d 6) Gelcarine #911
7) Gelcarine #621-ME
8) Firmtex
9 ) ~i-giucan ( 3 % )
h ) ~3-g lucan ( 5 0 )
The absorption qualities were rated as follows:
1) ~3-glucan 5% . . . best
2) Firmtex . . . . . close second
3/4) Viscarine #389 and ~-glucan 3%
(negligible difference)
5/6) Gelcarine and Solka Floc
(negligible difference)
7 ) starch acetate f lake
8) cellulose acetate micro fiber
9) cellulose acetate flake
10) Gelcarine #621-ME
The textural and organoleptic qualities were rated as
follows:
1) (3-glucan 5% . . . notably best
2) (3-glucan 3%
3) Firmtex
4) starch acetate flake
5) Solka Floc
6) Viscarine
7} Gelcarine #911
8) Gelcarine #621-ME
9) cellulose acetate micro fiber
10) cellulose acetate flake
The present invention is not limited to the
embodiments described herein, but may be varied and
modified within the scope of the appended claims.
i
