Influence of globulin subunit composition of soybean proteins on silken tofu quality. 1. Effect of growing location and 11SA4 and 7Sα’ deficiency

Growing location and genotypes are known to affect the subunit composition of the major storage proteins of soybeans, β-conglycinin (7S globulins) and glycinin (11S globulins), which have been associated with tofu quality. In this study, we examined 16 soybean genotypes grown at two locations in Queensland, Australia, for the influence of globulin subunit composition, growing location and genotype × growing location interaction on seed, soymilk and silken tofu properties. These genotypes comprised four groups: with all globulin subunits, without 11SA4, without 7Sα’, or without 11SA4 and 7Sα’. There were significant differences in the major protein subunits among the genotypes and the four groups and between locations. Significant genotypic and location differences were also observed in the properties of the seed, soymilk and silken tofu. There were no significant genotype × location interactions. The group without 11SA4 had less 11S and more 7S globulins, resulting in the lowest 11S/7S ratio. The silken tofu from this group had firmer texture and less water loss than the group containing all globulin subunits. The results suggested that genotypes of differing globulin subunit composition may produce tofu with different qualities and the effect of globulin subunit composition on tofu quality could be affected by growing location and the absence of certain globulin subunits.