Improvement of some quality attributes of soymilk through optimization of selected soybean sprouting parameters using response surface methodology

Abstract

This study aimed at producing functional soymilk by optimizing the sprouting conditions of soybeans using response surface methodology. Soaking (12–24 h) and germination times (48– 96 h) were optimized using central complete randomized design. Responses obtained from experimental runs were fitted into second order polynomial regression model. Significance of model parameters was tested using ANOVA and R2 was evaluated. The optimum sprouting conditions of soybeans were 12 h soaking and 52 h germination using desirability concept. Soymilk made from optimized conditions had 17% increase in total proteins, 50% reduction in phytic acid, 1.7% increase in total phenolics and a color change (ΔE) of 4.89 compared with the control. There was a significant reduction in trypsin inhibitor activity (0.03 mg/g TI), with increase in total amino acids and similar rheological properties in optimized soymilk. Optimized conditions obtained are adequate in the production of soymilk with improved nutritional and quality attributes.