EVALUATION OF SEVERAL SOURCES OF DIETARY FIBER FOR USE IN FOOD PRODUCTS
Date
1981-04
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
Type
Degree Level
Doctoral
Abstract
Properties of several fibrous byproducts from sunflowers, psyllium, flax, mustard, wheat and field peas were evaluated as potential fiber supplements for use in food products. The effect of particle size was examined by subdividing the sunflower hulls into coarse and fine fractions that differed primarily in particle size, and the wheat bran into coarse (bran) and fine (shorts) fractions that differed in composition as well. Each fiber supplement was characterized by its color, pH, relative density, relative shape and distribution of particle size.
Fiber from cellulose (99.5% neutral detergent fiber [NDF]), pea hulls (45.5% NDF) and sunflower heads (36.2% NDF) contained a high percent-age of cellulose, whereas fiber from the wheat bran fractions (51.7 and 36.4% NDF, respectively) contained a high percentage of hemicellulose. Fiber from flax hulls (30.6% NDF) and the sunflower hull fractions (97.0 and 98.0% NDF, respectively) contained high levels of lignin. Psyllium seeds (59.3% NDF) and mustard hulls (55.9% NDF) had high levels of both hemicellulose and cellulose. Sunflower heads contained 15-20% pectic substances. Psyllium seeds, flax hulls and mustard hulls contained 50, 21 and 12% mucilage, respectively. Approximately 30-50% of the mucilage was solubilized during the NDF analysis and 50-70% was measured as hemicellulose.
Sunflower heads, psyllium seeds, flax hulls and mustard hulls had the highest water absorption capacity, whereas cellulose had the lowest. The coarse fractions absorbed more water than the fine fractions. Sun-flower heads and sunflower hulls, wheat bran and cellulose absorbed twice as much fat as psyllium seeds, mustard hulls and pea hulls.
Each fiber supplement was fed ad libitum to male weanling Sprague-Dawley rats for three weeks. Diets contained 10% NDF, 16% protein and 8% fat. The flax hull diet depressed growth whereas, the sunflower hull diet depressed appetite. Sunflower heads, psyllium seeds, flax hulls and mustard hulls were the most effective bulking agents in the gastrointestinal tract, and were less digestible than wheat bran, sunflower hulls, pea hulls and cellulose. Flax hulls had the greatest effect on increasing stool weight and volume, and on decreasing apparent digestibility. Sunflower hulls effectively increased stool volume, but not stool dry weight. Sunflower heads and flax hulls lowered serum triglyceride. Differences in serum cholesterol were not significant.
Fiber-supplemented breads were prepared using the sponge-dough procedure with each fiber supplement replacing 7.5% of the wheat flour. Cellulose bread resembled the wheat bread control. The quality of the pea hull and wheat bran breads was similar to the whole wheat bread, with the pea hull bread having a light crumb color. Flax hulls and sunflower hulls
weakened the bread dough. Flax hull breads were small in volume and had a dark, red crumb. The coarse sunflower hulls imparted a gritty mouthfeel and a coarse crumb grain. The fine sunflower hulls also imparted a dark color to the crumb, although the fine particles interfered less with the bread structure than the coarse particles.
Fiber supplements were incorporated into bread and fed ad libitum to male weanling Sprague-Dawley rats for three weeks. Diets were formulated to contain 5% NDF, 16% protein and 8% fat. However, the bread diets were found to contain more lignin and less hemicellulose, cellulose and NDF than the raw ingredients. Rats fed the fiber breads had similar growth, feed consumption, digestibility, serum cholesterol and serum triglycerides as rats fed whole wheat bread. The sunflower hull breads, especially bread containing the coarse fraction, were more effective in increasing stool volume than whole wheat bread. The cellulose bread was less effective. Stool volumes of rats fed flax hulls, wheat bran and pea hulls were similar
to those of rats fed whole wheat bread.
Description
Keywords
DIETARY FIBER
Citation
Degree
Doctor of Philosophy (Ph.D.)
Department
Interdisciplinary Food Science Program