The effects of freezing on soybean microstructure and qualities of soymilk

This study was to investigate the effects of freezing on soybean microstructure and the qualities of soymilk made from the soybean by direct grinding in water without soaking. Transmission electron microscopic (TEM), particle size distribution determination and SDS–PAGE were used for the examination. TEM images showed that freezing treatment could induce the coalescence of protein storage vacuoles (PSVs) and oil bodies. Particle size distribution showed a trend that prolonging of freezing could decrease the average particle size of soymilk and increase the extraction efficiency of soybean. SDS–PAGE showed that extractable proteins were mainly composed of glycinin and β-conglycinin even after freezing. After freezing, soybean could be easily stored and could be used to make soymilk without soaking. The soymilk had a higher solid content and better stability than the soymilk from soybean without treatment. Thus, this study provided a convenient and short-time way to process soymilk at home.