Effects of Freezing Temperature on the Freeze-thaw Fractionation of Soymilk

Abstract

In this study, we investigated the effects of freezing temperature (−10°C, −30°C, and −80°C) on the freeze-thaw fractionation of soymilk. The physicochemical properties of soymilk samples were analyzed after freeze-thawing and fractionation (upper and lower layers). The weight ratios, protein and lipid contents, and 11S/7S ratios of the upper layers were essentially equivalent to those of the lower layers, regardless of the freezing temperature employed. On the other hand, the particle size of the lower layer increased as the freezing temperature was elevated. However, when the lower layers were heated, the particle size distributions were again found to be equivalent across the various freezing temperatures tested. Furthermore, the heated lower layers exhibited similar soymilk calcium coagulability and texture of the produced tofu curd across the various freezing temperatures. These results suggested that the fractions obtained by the freeze-thaw fractionation of soymilk were unaffected by freezing temperature.