EFFECT OF PROCESSING ON IN-VITRO DIGESTIBILITY OF PROTEIN AND STARCH IN QUINOA SEEDS

The in vitro digestibility of protein in raw quinoa assessed by an enzymic method was 78%, significantly (P < 0.01) lower than that of casein, 91%, and also somewhat lower (P < 0.01) than that of the raw washed quinoa sample, 83%. The process used to remove the outer layers of the seeds containing saponins increased the protein digestibility significantly (P < 0.01), by 7%. Heat treatments increased protein digestibility over that of raw quinoa samples. Only the cooked sample treated for 60 min presented a slightly lower protein digestibility, 77%, than those obtained for other heat-treated samples. The temperature, time and moisture used in cooking and autoclaving of whole seeds of quinoa did not improve starch digestibility significantly. The digestibility of the starch in the raw and precooked samples was 72 and 77%, respectively, after drum drying and about 64% after extrusion in both cases. Precooking at 60-degrees-C for 20 min does not improve the digestibility of the quinoa starch.