Influence of pre-blanching on the water absorption kinetics of soybeans

The influence of a pre-blanching step on water absorption kinetics of soybeans was investigated. Three models, commonly used to describe the soaking kinetics of legumes, were fitted to the data and compared in terms of their resultant pooled Akaike Information Criterion (AIC). A first-order asymptotic model resulted in the lowest AIC, and was therefore selected to investigate the effect of temperature and pre-blanching on the process of water absorption. A general model was developed to describe moisture content as a function of pre-treatment, soak time and temperature. From the model, it was predicted that pre-blanching could decrease the soak time by up to 2 h. However, the effect of pre-blanching diminished as soak temperature was increased, and blanching was not beneficial (in terms of soaking time) for samples soaked at temperatures above 55 °C. Blanching also resulted in a significant decrease of soybean-surface microbial levels (p < 0.05). The results demonstrate that pre-blanching can be especially beneficial to soybeans soaked at low temperatures (25-50 °C), by decreasing initial microbial counts and shortening the soaking time required.