17G-24 |
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J. R. HERNÁNDEZ-DÍAZ1, R. R. Balandrán-Quintana1, A. Quintero-Ramos1, and J. Barnard2. (1) Facultad de Ciencias Químicas, Universidad Autónoma de Chihuahua, Ciudad Universitaria S/N, Chihuahua, 31170, Mexico, (2) Food Science & Technology, Cornell University, New York State Agricultural Experiment Station, 630 W. North St., Geneva, NY 14456-1371 Blends from cereal and legumes are suitable for extrusion cooking in order to obtain foods with enhanced nutritional properties. Usually fiber is removed from meal and only the starch or protein rich fractions are extruded, so the effect of crude fiber on functional properties of extrudates is not evaluated. Our objective was to evaluate the effect of extrusion conditions and the addition of wheat bran to a blend of Pinto bean meal:wheat flour, on functional properties of extrudates. Blends from wheat flour:bean meal (60:40) with added wheat bran (0, 5, 10, 15 and 20%) were adjusted to 16, 18, 20, 22 and 24% moisture content (MC) and subjected to extrusion cooking at 160, 170, 180, 190 and 200ºC, and 160, 180, 200, 220 and 240 rpm screw speed. Extrudates were analyzed for expansion index (EI), bulk density (BD), apparent viscosity (AV), water absorption index (WAI) and water solubility index (WSI) using a second order rotatable central composite design. Excepting WAI, functional properties were significantly affected (p<0.05) by moisture, wheat bran content (BC) and extrusion conditions. EI and BD decreased with increasing BC and MC in the blends; EI ranged from 1 to 1.8 and BD from 0.62 to 0.79. AV increased with increasing MC and screw speed until a maximum of 2,572 centipoises was reached at 24% MC and 220 rpm. WSI decreased with increasing levels of BC and MC and ranged from 0.0855 to 0.1590. The increased AV and reduced WSI reflect minor damage to macromolecules like starch and proteins, which was attributed to a protective role of the added fiber. Our experiments produced extrudates with acceptable EI, suitable for applications that involve water absorption. Moreover, the combination of legumes and cereals in the development of products is beneficial as these extrudates have potential with both functional and health advantages.
Session 17G, Food Engineering: Physical, chemical and electrical properties
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