Yield and quality of soymilk and tofu made from Manitoba-grown food grade soybeans
Reimer, Michael Chad
Effects of variety and environment on seed characteristics and processing potential of Manitoba-grown food-grade soybeans were determnined and compared to Harovinton, a well-established Canadian food-grade soybean variety. Seed size and seed protein and sucrose content were measured. A laboratory-scale procedure for soymilk and tofu production was adapted to evaluate soymilk yield and colour and tofu yield, colour, and hardness. Eleven soybean varieties at three sites (Carman, Morris, Rosebank) were evaluated in 2005 and ten soybean varieties at three sites (St. Adolphe, Morris, Rosebank) were evaluated in 2006. Both site-year and variety main effects were found to significantly affect soybean seed characteristics (protein), soymilk colour, and tofu hardness (P <0.0001). The site by year interaction was significant for seed protein, soymilk colour, and tofu hardness. Seed size for Manitoba-grown soybean varieties were generally smaller than the commercial Harovinton sample; exceptions were the varieties OT05-21 and OT05-20, which were only grown in 2006. Protein content of the varieties CL987704, Kaminchis and Lotus, grown in 2005 only, were similar to Harovinton; however, all other Manitoba-grown soybeans were lower in protein content. The varieties OAC Prudence, Jim, OAC 01-12, OAC Erin and OT05-20 grown in 2006 had higher seed sucrose content than Harovinton. For soybeans with lower protein content, soymilk and tofu yield and tofu color were lower than for Harovinton. Soymilk colour and tofu hardness for all Manitoba-grown soybeans compared well to Harovinton. While it is possible to make acceptable soymilk and tofu from Manitoba-grown soybeans, the cultivars that meet acceptable agronomic criteria are deficient in termns of yield and/or seed size.