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J Sci Food Agric 1998, 77, 179È183
Barley b-Glucan is Eþective as a
Hypocholesterolaemic Ingredient in Foodss
Kari D Hecker,” Mary L Meier, Rosemary K Newman* and C Walter Newman
Montana State University, Department of Plant, Soil and Environmental Sciences, Bozeman, MT 59717,
USA
(Received 21 August 1997 ; accepted 6 October 1997)
Abstract : Barley contains high levels of soluble dietary Ðbre, including mixed
linked 1 ] 3, 1 ] 4b-D-glucans (b-glucan). An extract of b-glucan from waxy,
hulless barley containing 56% total dietary Ðbre (TDF) was incorporated into
Ñour tortillas, cornstarch pudding and apple granola bars to provide 2 g soluble
Ðbre as b-glucan per serving. The foods were tested for objective functional
properties. Flour tortillas with b-glucan were incorporated into rat diets and
compared to diets containing an equivalent amount of cellulose, to test the Ðbre
e†ect on growth and lipid metabolism parameters. Rats fed b-glucan tortillas had
lower feed consumption and body weight (P \ 0É05) compared to those fed the
cellulose tortillas, although feed/gain ratios were not di†erent (P [ 0É05). Plasma
LDL-cholesterol of rats fed b-glucan was lower (P \ 0É05) than cellulose-fed controls, although total cholesterol and triglycerides did not di†er (P [ 0É05). Rats
fed b-glucan tortillas had higher (P \ 0É05) faecal fat excretion, suggesting
impairment of intestinal fat absorption. Liver composition data showed lower
(P \ 0É05) levels of total lipid and cholesterol in b-glucan-fed rats. The results
suggest that the barley b-glucan concentrate has potential as a food ingredient to
provide supplemental soluble Ðbre which may be beneÐcial in reducing plasma
LDL-cholesterol in humans. ( 1998 SCI.
J Sci Food Agric 77, 179È183 (1998)
Key words : barley ; b-glucans ; cholesterol ; soluble Ðbre
INTRODUCTION
cosity in the intestine, and e†ect on the bile acidÈ
cholesterol cycle (Story 1986 ; Wang et al 1992). Barley
contains high levels of soluble dietary Ðbre, particularly
mixed linked 1 ] 3, 1 ] 4 b-D-glucans, and has been
demonstrated to have hypocholesterolaemic e†ects in
experimental animals and humans (Fadel et al 1987 ;
Newman et al 1989 ; McIntosh et al 1991).
Utilisation of barley as a food grain has been
reviewed and there is a potential for many forms of
barley as ingredients in a wide variety of foods
(Newman and Newman 1991). Incorporation of large
percentages of barley grain to produce high Ðbre foods,
however, may not always be practical or desirable. Concentrated b-glucan extracts from barley and oats have
been demonstrated to have hypocholesterolaemic
properties (Newman et al 1993).
The present study was conducted to evaluate the use
of a barley b-glucan concentrate as a Ðbre-enriching
food ingredient. The speciÐc objectives were to increase
Interest in dietary Ðbre has increased recently due to its
beneÐcial e†ects on blood cholesterol levels, glycaemic
responses, and associated risks for chronic diseases
(Pilch 1987). Total dietary Ðbre (TDF) consists of insoluble fractions, both of which are resistant to digestion
by the alimentary enzymes of humans (Slavin 1987). The
insoluble fraction in cereal grain contains a large proportion of cellulose and is noted for its beneÐcial e†ects
in the gastrointestinal tract (Jenkins et al 1986). The
soluble fraction, which contains mostly pectin, arabinoxylan, and b-glucan, has the ability to lower blood
serum cholesterol, through its tendency to increase vis* To whom correspondence should be addressed.
¤ Contribution No J-5057, Montana Agricultural Experiment
Station, Bozeman 59717.
” Present address : University of Missouri, Department of
Human Environmental Sciences, Columbia, MO 65211, USA.
179
( 1998 SCI.
J Sci Food Agric 0022È5142/98/$17.50.
Printed in Great Britain
K D Hecker et al
180
soluble Ðbre by 2 g per serving in three di†erent food
products. Serving sizes were one Ñour tortilla, one-half
cup of cornstarch pudding and one 8 cm apple granola
bar. These products, previously tested for acceptability,
were selected as representative foods that might be consumed either as snacks or, in the case of tortillas, breadstu† for a variety of menu items. The Ñour tortillas were
tested for cholesterol-lowering properties in a rat
experimental model and all three foods were tested for
functional quality.
MATERIALS AND METHODS
Fibre concentrate
b-Glucan concentrate, a Ñavourless white powder, was
obtained from Centennial Foods Inc (Dillon, MT,
USA). The composition was : 7É11% moisture ; 0É95%
ash ; 0É10% fat ; 3É59% protein ; and 55É60% b-glucan,
the remainder consisting of oligosaccharides.
Product preparation and objective evaluation
Flour tortillas were prepared using a standard formula
containing 446 g Ñour (Gold Medal, General Mills Inc,
Minneapolis, MN, USA), 5 g salt (Albertsons Inc, Boise,
ID, USA), and 28 g baking powder (Calumet, White
Plains, NY, USA). For the experimental tortillas, 50 g
of b-glucan concentrate was substituted for an equivalent amount of Ñour and added with the dry ingredients.
Thirty grams of lard (Rex Manteca, Bar-S Foods Co,
Phoenix, AZ, USA) was then added to the dry ingredients and the mixture was stirred to the consistency of
peas. Warm (40¡C) tap water (336 g) was gradually
added while stirring ingredients to form a ball of dough.
After the ball was formed, it was kneaded for 5 min and
placed in a bowl, covered with a towel and let stand for
20 min at room temperature. Eighteen equal portions
were then weighed out and rolled on a pasta press
(Berarducci Bros Mfg Inc, level 4). The tortillas were
placed on a hot griddle (West Bend Sensa Temp, West
Bend, WI, USA), at 121¡C and cooked for 45 s on each
side.
Tenderness of the tortillas was tested using the
Warner-Bratzler Shear Apparatus (G-R Elec Mfg Co,
Manhattan, KS, USA). Three samples of each product,
both control and experimental, were tested once and the
average of the three results used to determine tenderness. Storage stability, determined by rollability of
stored tortillas, was evaluated. Three samples of control
and experimental tortillas were tested every other day
for 7 days, and scored according to Friend et al (1992).
The rollability scale ranged from 1È5, as follows : (1) no
cracking (best) ; (2) signs of cracking but no breaking ; (3)
cracking and breaking beginning on one surface ;
(4) cracking and breaking imminent on both sides ; and
(5) unrollable, breaks easily (poorest). Since sample tortillas were stored in a refrigerator, they were heated in
a microwave on full power for 6 s before each test, then
rolled around a 0É64 cm dowel and judged according to
the above scale.
Cornstarch pudding was prepared by a standard
method (Morr and Irmiter 1990), the formula containing 18 g cornstarch (KingsfordÏs, Best Foods CPC
International Inc, Englewood Cli†s, NJ, USA), 48 g
granulated sugar, 1 g salt (AlbertsonÏs Inc, Boise, ID,
USA), 15 g margarine (AlbertsonÏs Inc, Boise, ID, USA),
8 g vanilla (Schilling, McCormick & Co Inc, Hunt
Valley, MD, USA), and 53 g beaten egg yolk. For the
experimental pudding, 5 g b-glucan concentrate was
added with the dry ingredients. For the control
pudding, 239 g of skim-milk (Darigold Inc, Seattle, WA,
USA) was added, and the amount for the experimental
pudding was increased to 270 g to compensate for the
water-holding capacity of the b-glucan. Pudding viscosity was determined using a line-spread apparatus
(McWilliams 1987), measured in consistometers. Duplicate samples of 100 g each of control and experimental
puddings were measured at 55 and 64¡C. The measured
samples were placed in a bottomless styrofoam cup with
a diameter of 4É6 cm, on measured concentric rings and
allowed to Ñow for 2 min. At the end of each 2 min
trial, the spread at each 90¡ increment of the circle was
read. Line-spread values are the means of the four
values obtained.
Control and experimental apple granola bars were
prepared as follows : 223 g brown sugar (California and
Hawaiian Sugar Co, Concord, CA, USA), 57 g creamy
peanut butter (Simply Jif, Procter and Gamble, Cincinnati, OH, USA), 36 g light corn syrup (Karo, Best
Foods, CPC International Inc, Englewood Cli†s, NJ,
USA), 53 g whole egg, 117 g margarine (AlbertsonÏs,
Boise, ID, USA), and 260 g apple Ðlling (Solo, Sokol &
Company, Countryside, IL, USA) were combined in a
large bowl and blended. The remaining ingredients, 7 g
vanilla (Schilling, McCormick & Co Inc, Hunt Valley,
MD, USA), 1 g salt (AlbertsonÏs Inc, Boise, ID, USA),
0É35 g ground cinnamon (Schilling, McCormick & Co
Inc, Hunt Valley, MD, USA), 269 g quick-cooking oats
(Quaker Oats Company, Chicago, IL, USA), 107 g
whole wheat Ñour (Gold Medal, General Mills Inc,
White Plains, NY, USA), 57 g Ñaked coconut (Kraft
General Foods Inc, White Plains, NY, USA), 25 g sunÑower nuts (Gold Shield, PaciÐc Foods Inc, Kent, WA,
USA), 28 g wheat germ, and 22 g sesame seeds were
added in sequence, blending well between each addition.
The mixture was then pressed evenly into a well greased
33 ] 23 ] 5 cm pan and baked at 177¡C for 35 min
until golden brown. The experimental bars were prepared using the same ingredients with the exception of
using 88 g corn syrup, 378 g apple Ðlling, 87 g whole
wheat Ñour and 59 g b-glucan concentrate. Because the
b-glucan concentrate has high liquid-holding capacity,
Hypocholesterolaemic e†ects of barley b-glucan
181
the increased amounts of corn syrup and apple Ðlling
were added and the Ñour quantity was adjusted to
achieve a comparable consistency to the control
product. The apple granola bars were tested for tenderness using the same methods as for the Ñour tortillas.
Physiological and cholesterol-lowering properties
The cholesterol-lowering property of the b-glucan
enriched tortillas was tested in a rat feeding study. The
control tortilla used for the rat experiment was made
using the same formula as used in objective evaluation,
except for the substitution of 27 g of cellulose (to equalise TDF) for this amount of wheat Ñour. Rat diets
(Table 3) met all nutrient requirements of laboratory
rats (NRC 1978). Twenty Sprague-Dawley rats, 22È26
days old, were acclimated in an approved animal facility
and fed a standard pelletised diet with a 12 : 12
light : dark schedule for 5 days. All conditions conformed to the NRC standards (NRC 1985). Rats were
weighed and assigned to two groups with equalised
weight ranges between 133 and 147 g. Animals were
placed in individual cages and fed diets containing tortillas with either cellulose (control) or b-glucan for 25
days. Rats were weighed weekly, diet consumption
reported every four days, and feed waste estimates made
twice weekly. Total faecal collections were taken on
days 17 to 19, and samples were freeze-dried and stored
at [20¡C prior to analysis. On day 25, rats were fasted
for 12 h before blood samples were taken by heart
puncture. Rats were killed with carbon dioxide and
livers excised, weighed and frozen at [20¡C for later
analysis.
Chemical analysis
The three food products and the test diets were
analysed for content of soluble and insoluble dietary
Ðbre (Prosky et al 1988), protein (N ] 6.25), ether
extract and ash (AOAC 1984).
Plasma was analysed for total cholesterol (Allain et al
1974), triglycerides (Tietz 1987), and HDL-cholesterol
(Finley et al 1978) on a Kodak DT 60 analyser
(Eastman Kodak, Rochester, NY, USA). Plasma LDLcholesterol was calculated as described by Friedwald et
al (1972) and faecal total lipid content was analysed
(Anon 1971). Livers were analysed for lipids (Folch et al
1957) and total cholesterol (Warnick et al 1982).
Statistical analysis
Data were analysed using SAS General Linear Models
Procedure and di†erences between means were analysed
by Least Square Means (SAS 1988).
RESULTS AND DISCUSSION
Chemical analysis
Table 1 shows the analysed composition of food products. Control and experimental versions of each
product had comparable fat, ash and protein content,
except for the apple granola bars, which had considerably lower fat in the b-glucan version due to added carbohydrate ingredients. Fibre content varied between
control and experimental products relative to the added
b-glucan.
Objective evaluations
Results of objective tests on food products are shown in
Table 2. In tenderness tests, the control tortillas used an
average of 0É15 kg of pressure compared to 0É127 kg for
those containing b-glucan, indicating slightly more tenderness for the latter. In rollability, control tortillas
scored “1Ï on the initial trial (day 0), while b-glucan tortillas scored “2Ï. Thereafter, there were no di†erences in
rollability scores between control and b-glucan tortillas.
Decreasing scores (higher numbers) over time indicated
gradual deterioration in consistency. Storage stability of
TABLE 1
Composition of food products (DM%)
Item
Tortillas
Control
b-Glucan
Pudding
Control
b-Glucan
Apple granola bars
Control
b-Glucan
Fat
Ash
Protein
Fibre
Insoluble
Soluble
T otal
5É3
5É7
4É1
3É6
9É5
9É9
2É0
2É3
1É7
10É2
3É7
12É5
12É0
10É5
2É8
2É9
8É1
8É6
0É5
0É4
0É1
2É0
0É6
2É4
18É1
12É6
1É7
1É5
9É9
8É2
3É6
3É1
1É4
3É3
5É0
6É4
K D Hecker et al
182
TABLE 2
Objective tests of food productsa
Product
T ype test
Control
TABLE 3
Composition of rat diets (% of diet)
b-Glucan
Tortillas
Tenderness
(kg pressure)
Rollability scores
Day 0
Day 2
Day 4
Day 6
0É15
0É127
1
3
4
5
2
3
4
5
Pudding
Viscosity
(linespread cm)b
0 minc
5 min
7É1
6É5
10É9a
8É3a
Tenderness
(kg pressure)
0É69
1É12
Apple granola bars
a Values followed by di†erent letters are statistically di†erent
than control products at a signiÐcance level of P \ 0É05.
b Viscosity : cm per 2 min spread.
c Cool time.
the tortillas could be improved by ways such as those
shown in Friend et al (1992) and Suhendro et al (1993)
who reported a reversal of poor storage stability in high
Ðbre and protein-enriched tortillas, respectively, by
addition of wheat gluten.
Line spread tests showed the control pudding to be
more viscous (smaller area spread) than the pudding
with b-glucan at 0 and 5 min cooling times. This is an
interesting phenomenon, in that uncooked b-glucan is
known to possess high viscosity in grain extract analysis
and in the intestine of experimental animals (Wang et al
1992).
In tenderness testing of the apple granola bars, the
control bars were more tender with an average of
0É69 kg of pressure compared to 1É12 kg for bars with
b-glucan.
Physiological properties
Feed consumption of rats, body weight gain and feed/
gain ratios are shown in Table 4. Rats fed b-glucan consumed less feed and gained signiÐcantly less body
weight (P \ 0É05) than those fed the control tortilla,
although there was not a signiÐcant di†erence in feed/
gain ratio. The LDL-cholesterol was signiÐcantly lower
(P \ 0É05) in rats fed b-glucan tortillas, but there were
no di†erences in total cholesterol, HDL-cholesterol or
triglycerides between the two groups.
Rats fed b-glucan tortillas had higher (P \ 0É05)
faecal excretion of fat, suggesting that b-glucan interfered with fat absorption. These results agree with
earlier results reported for barley (Fadel et al 1987),
Ingredient
Control
Experimental
b-Glucan tortilla
(13% TDF)
Cellulose tortilla
(13% TDF)
Casein
Peanut oil
AIN mineral mix
AIN vitamin mix
Cholesterol
Sodium cholate
Antioxidant
DL-Methionine
Lysine
Cornstarch
Dye
Analysed composition
(DM%)
Total dietary Ðbre
Soluble Ðbre
Insoluble Ðbre
Total protein
Total fat
È
80É00
80É00
È
7É7
4É4
3É5
1É0
1É0
0É20
0É01
0É31
0É04
1É8
0É01
7É3
4É7
3É5
1É0
1É0
0É20
0É01
0É33
0É01
1É9
0É01
10É4
1É3
9É1
14É8
10É1
9É5
7É8
1É7
13É9
10É5
barley b-glucan concentrate and oat concentrate
(Newman et al 1993). Livers of rats fed b-glucan tortillas
had lower (P \ 0É05) levels of total lipid and cholesterol
than the controls, suggesting a metabolic shift toward
reduced total blood cholesterol. These results are supportive of earlier studies reporting the cholesterolTABLE 4
Feed consumption, weight gain and metabolic parameters of
rats tortilla dietsa
T ortillas Diet group
with
tortillas with
cellulose
b-glucan
Totals for 25 days
Food consumption (g)
Body weight gain (g)
Feed/gain
Plasma lipids (mmol litre~1)
Total cholesterol
HDL-cholesterol
LDL-cholesterol
Triglycerides
Faecal fat (DM%)
Livers
Total lipids (g g~1 tissue)
Cholesterol (mg g~1 tissue)
430É0
162É0
2É66
2É82
1É45
1É13
0É38
7É8
15É0
34É7
392É5a
146É2a
2É69
SEb
6É8
2É8
0É04
2É38
1É63
0É68a
0.33
13É3a
0É22
0É12
0É12
0É03
0É40
11.4a
25É1a
0É80
1É60
a Values followed by di†erent letters are statistically di†erent
than control group at a signiÐcance level of (P \ 0É05).
b Standard error of the least square means.
Hypocholesterolaemic e†ects of barley b-glucan
lowering properties of barley grain (Newman et al
1989), and are particularly important as a demonstration of the use of extracted b-glucan concentrate as a
soluble Ðbre supplement in palatable food products.
CONCLUSIONS
Current dietary recommendations for Americans specify
25È35 g of total dietary Ðbre per day, of which onequarter should be soluble (Pilch 1987). The best
common sources of soluble Ðbre are beans, other vegetables, fruits, oats and barley. Barley b-glucan extracted
from the grain is a tasteless, odourless white powder
which can be incorporated into snack foods and breadstu†. The inclusion of 2 g soluble Ðbre per serving in
pudding, granola bars and tortillas is an example of
Ðbre enrichment that can contribute to consumer consumption approaching the recommended levels of Ðbre.
In this study, one of these foods was shown to have
hypocholesterolaemic properties.
ACKNOWLEDGEMENTS
This research was partially supported by the Montana
Wheat and Barley Committee, Box 3024, Great Falls,
MT 59403. Petrea Hofer assisted with chemical analysis
and care of animals.
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