Yield and quality of soymilk and tofu made from soybean genotypes grown atfour locations

Soyfoods are becoming popular among American consumers because of potential health benefits. However, specific information about the kind of soybean [ Glycine max (L,) Merr.] seed desirable for soyfoods preparation is limited. The objectives of this study were to compare soymilk and tofu prepared fro m 12 soybean genotypes grown at four locations in the southern USA during 1 995 to identify genotypes suitable for soymilk and tofu manufacture and to determine effects of seed traits on yield and quality of soymilk and tofu. Location effects were significant only for soymilk solids and tofu strength . Soymilk yield with a mean value of 5.1 mt g(-1) seed was not affected by soybean genotype. Significant genotypic effects were observed on tofu yield , which varied from 0.82 to 0.91 g mL(-1) of soymilk. Tofu yield was signif icantly correlated to seed size (+ 0.31), seed oil (+ 0.74), rate of water absorption after 1 and 16 h of soaking (+ 0.38 and + 0.56, respectively), a nd seed protein (-0.82). Seed protein content, seed size, and soymilk solid s were significant determinants of tofu yield (R-2 = 0.80). Two variables, soymilk index (SI) and tofu index (TI), were calculated to compare overall suitability of soybean genotypes for soymilk and tofu production. SI was ca lculated by summing yield, total solids, protein content, and whiteness ind ex of soymilk. TI was calculated by summing yield, protein, whiteness index , and strength of tofu. Seed oil content and size were significant determin ants of SI (R-2 = 0.41), whereas soymilk color, seed size, and seed protein content were significant determinants of TI (R-2 = 0.52) The SI and TI val ues indicated BARC-9 to be a desirable genotypes for soymilk and for tofu p reparation.