29C-15 |
Fiber supplements and the physical properties of legume extrudates |
M. CHENG1, J. D. J. Berrios2, J. Tang1, B. G. Swanson3, and R. J. Garnanez3. (1) Dept. of Biological Systems Engineering, Washington State Univ., PO Box 646120, Pullman, WA 99164-6120, (2) Processed Foods Research Unit, USDA-ARS-Western Regional Research Center, 800 Buchanan St., Rm. 0204, Albany, CA 94710-1105, (3) Dept. of Food Science & Human Nutrition, Washington State Univ., PO Box 646376, Pullman, WA 99164-6376 High fiber-supplemented functional snack or breakfast foods could be consumed to improve average intakes of dietary fiber in USA diet which is only half of the recommend amount. However, fiber supplements may damage the appearance and texture of extrudates, which play major roles to product quality. The objective of this study was to investigate the possibility of dietary fiber supplements to legume extrudates. Seeds of two legume cultivars, Yellow Split Pea (YSP) and Red Chief Lentil (RCL) were processed using a twin-screw extruder with different dietary fiber. The influences of fiber sources (apple pomace fiber and wheat bran) and related concentration levels (5%, 10%, 15% and 20%) were studied by determining expansion index (EI), relative diameter difference (RD), density, color and texture profiles of the corresponding extrudates. The texture profiles of extrudates were also compared with those of six commercial extruded snacks. It was found that fiber supplements decreased EI and increased the density linearly with increasing fiber concentrations. No significant differences were observed between YSP and RCL when considering EI. Addition of fiber reduced RD while slightly darkened the extrudates due to its original brown color. Hardness and strength of extrudates increased significantly when increasing fiber concentration. Equivalent amounts of apple pomace fiber affected more remarkably than wheat bran did on the physical properties of extrudates, except for color. The results also demonstrated that peas and lentils extrudates exhibited equivalent texture as commercial extruded snacks did with similar moisture contents. This study indicated that fiber may reduce the quality of legume extrudates slightly, but it is still promising to be a nutrition supplement to the expanded foods based on legume flours.
Session 29C, Food Engineering: Rheology and texture
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