Physico-chemical characterization of dietary fiber sources

The physico-chemical characteristics of several dietary fiber sources—wheat bran, corn bran, peanut hull, oatmeal, alfalfa and alpha-cell (cellulose) were studied. All samples were dried in a vacuum-oven and ground until the particles would pass a U.S. Std. Sieve No. 30 but would not pass U.S. Std. Sieve No. 80. The ground samples were analyzed for acid-detergent fiber, acid-detergent lignin, water-holding capacity, bile salt binding, cation-exchange and emulsifying capacities. Proximate analysis of all samples was performed. Based on the results of this experimental study, the following con-clusions were made: Of the six samples, alpha-cell (cellulose) had the highest and oatmeal the lowest acid-detergent fiber content. Peanut hull had the highest and oatmeal the lowest acid-detergent lignin content. There were significant differences among the means of all samples (p<0.05). Among all samples, alfalfa possessed the highest water-holding capacity and oatmeal the lowest. There were significant differences among all means (p<0.05). Alfalfa possessed the highest bile salt binding capacity, followed by oatmeal, but little variation among the means was observed (p<0.05). For cation-exchange capacity oatmeal showed an unusually high cation-exchange capacity, followed by alfalfa. Peanut hull had the lowest cation-exchange capacity. No significant differences among the means of the five groups were observed (p<0.05). As for emulsifying capacity, alfalfa possessed the highest emulsifying capacity. Peanut hull showed the least emulsifying capacity and Duncan's Multiple Range test allowed partitioning of the means into three unique groups (p<0.05). Acid-detergent fiber and acid-detergent lignin did not exhibit strong correlation with any of the functionalities studied. A significant linear relationship was observed between ash and bile salt binding (r = 0.84). No significant relationship was observed among different functionalities (water-holding capacity and bile salt binding, water-holding capacity and cation-exchange capacity and cation-exchange capacity and bile salt binding capacity) except for water-holding capacity and cation-exchange capacity (r = -0.83).