312 Digestion profile of extruded rice flour using a-amylase.

R. J. BRYANT (1), R. Kadan (2), and D. Boykin (3). (1) USDA, ARS, DB NRRC, Stuttgart, AR 72160; (2) USDA, ARS, SRRC, New Orleans, LA 70124; (3) USDA, ARS, Stoneville, MS 38776.

Waxy (short grain), long grain, and parboiled (long grain) rice flour were evaluated for their digestion profile after extrusion cooking in a co-rotating twin-screw extruder. The main difference in the digestion profiles was due to temperature. The flours extruded at 100 C were digested significantly slower than those extruded at 125 and 150 C. Significant differences were not detected in the digestion profile of the three rice flours for a given temperature and moisture (P > 0.05) with the following exceptions: long grain and parboiled extruded at 100 C and 15% added moisture (F = 4.48, P = 0.03); and long grain and parboiled extruded at 150 C and 20% added moisture (F = 3.72, P = 0.05). Moisture appeared to have little effect on the digestion profile of the modified rice flour for a given temperature, except when parboiled was extruded at 150 C. The digestion rate for 11 and 25% added moisture was significantly less than that for 20% (P 0.05).