A small-scale tofu test for soybean breeding programs

Abstract

Soybean breeding programs targeting tofu production must identify cultivars that are well suited for making tofu. A small-scale (SS) test of tofu texture was developed to evaluate breeding lines. The SS tofu test was developed to complement the larger scale Harrow tofu test but to use smaller samples of seed and soymilk to make tofu. The SS tofu test uses both magnesium chloride (MgCl2) and glucono-delta-lactone (GDL) coagulants to produce tofu samples of 20 mL. In comparisons of the SS and Harrow tofu texture tests, using lines with varying protein subunit profiles, both tests ranked lines similarly. In plant breeding trials, the SS tofu test was useful in ranking varieties for tofu texture. Multiple-year testing should be used for a thorough evaluation of varieties. When the SS tofu test was used with a population of lines with a wide range of seed protein, GDL-coagulated tofu texture was independent of seed protein content; however, MgCl2-coagulated tofu texture was moderately inversely correlated with seed protein. With the SS test, it may be best to compare tofu texture within groups of lines with similar seed protein levels. The SS tofu test is useful to test tofu texture of breeding lines using small amounts of seed.