Effects of dehulling and storage conditions on cooking requirements and chemical composition of soybeans / Efecto del descascarado y de las condiciones de almacenamiento en los requerimientos de cocción y composición química de la soya

Changes in cooking requirements and chemical composition of whole and dehulled soybeans, stored in 2 different environments [25ºC/75 per cent RH. (Environment 1) and 38ºC/90 per cent RH. (Environment 2)], were studied. Rate of water absorption and solid losses during cooking were higher for the dehulled soybeans at both storage conditions. However, cooking requirements to archieve the same degree of texture cotyledons were similar for whole and dehulled seeds. Cooking time increased with prolonged storage; the effect was more noticeable in samples stored under Environment 2. Samples kept for 6 months almost twice as much cooking than control samples. dehulled soybeans had a lower fiber content, relatively higher amounts of protein and fat, but similar amino acid compositions than whole soybeans. Cooking caused losses of carbohydrates and ash and, therefore, significantly increased levels of protein and fat reflected by losses of solids during soaking and cooking. Among the amino acids, only cysteine suffered subtantial decrease as a result of cooking. Cooking and storage inactivated 90 per cent and from 20-35 per cent of the trypsin inhibitors, respectively; the latter effect was more accentuated in samples stored under Environment 2

Effects of dehulling, cooking and storage conditions on protein quality and digestibility of soybeans / Efecto del descascarado, cocción y almacenamiento sobre la calidad de la proteína y digestibilidad de la soya

Soybeans were debulled, stored under two environmental conditions [25ºC/75 por ciento RH (Env. 1) and 38ºC/90 por ciento RH (Env. 2)], optimally cooked and assayed for trypsin inhibitor and protein quality with laborary rats. Dehulling not significantly effects protein quality (PER and NPR) and protein digestibility of raw and cooked soybeans. Raw soybeans diets were significantly poorer in protein quality and digestibility when compared with cooked counterparts. PER values of dehulled-cooked soybean diets decreased significantly (p<0.05) as seeds were stored for up to 3 months under either environment. These were no significant differences in PER values due to etorage suring the period from 3 a 6 months. PER values for whole-cooked soybean diets exhibited a significant decline only when stored for 6 months under Env. 2