2001 AACC Annual Meeting Charlotte, North Carolina October 14-18, 2001 Charlotte Convention Center

Legumes are a good source of unique starch, highly soluble protein and dietary fiber. By fractionating legumes into these main components, both their utilization and market value can be increased. The objectives of this research were to develop an efficient method of isolating dietary fiber from peas, chickpeas and lentils, and to determine the composition and functional properties of the isolated fiber. Seeds were milled into flour using a roller mill and separated into prime starch, tailings starch and water solubles using a wet fractionation method. Insoluble dietary fiber was isolated from the tailings starch by wet screening through sieves with various openings and analyzed for yield and purity. Soluble dietary fiber was isolated from the water-soluble fraction by enzymatic digestion of protein and precipitation of fiber. Total dietary fiber content of legume flours ranged from 10.7-14.3%, starch content ranged from 45.8-52.1% and protein ranged from 23.6-27.6%. Yields of prime starch, tailings starch and water solubles from wet fractionation were 28.9-30.8%, 22.9-25.5% and 36.3-39.9%, respectively. Insoluble dietary fiber yields increased as the sieve opening size decreased while purity remained relatively constant within each species for all sieves. Starch content of isolated insoluble fiber ranged from 14.7 to 31.1% and protein content from 7.1 to 13.2% depending on the sieve size and legume species. Yields and purity of insoluble fiber from each sieve were similar for peas and lentils while chickpeas had the lowest yields and purity.