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

The effect of soaking time on water time on water absorption and solid losses of whole and dehulled soybeans / Efecto del tiempo de remojo en la absorción de agua y pérdida de sólidos en soya entera y descascarada

Dehulled entire soybean cotyledons are required for the preparation of many interesting products. Removing hulls had a dramatic effect on the rate of water uptake during soaking. Maximum uptake was reached in only 3 hr compared to the 12 hr needed by whole beans. This saves time and reduces microbial groeth during soaking. The amount of water absorbed by beans, with and without hulls, was similar once corrected for solid losses and surface water. Removal of fibrous shells during dehulling increased both the protein and oil contents by 2 per cent. Dehulled beans steadily lost solids during soaking. Losses were 8.6 per cent compared to 0.7 per cent whole beans when maximum uptakes were first reached. Way of avoiding or reducing these losses are discussed