Physicochemical Characteristics of Soft Tofu Formulated From Selected Soybean Varieties1

Abstract

Currently, hundreds of soybean varieties with a wide range of quality attributes are available. The majority of these soybean varieties have not been evaluated for their quality in soymilk and tofu. In this research, tofu was prepared using the hot ground method by coagulating soymilk from four soybean varieties (Macon, Saturn, OHIOFGI and OHIOFG2) with calcium sulfate dihydrate. Soybean variety significantly affected yield, held water, color parameters, viscosity, storage modulus, and textural properties of tofu cakes. Soymilk with higher pH, viscosity, and protein produced tofu with higher protein, wafer held, and yield. Varietal differences should be considered in selecting soybeans for tofu production. Macon soybeans produced the best tofu with regards to quality attributes.

Comparison of Two Small-Scale Processing Methods for Testing Silken Tofu Quality

“…Tofu colour was evaluated using the CIE L*a*b* colour system in this study, and the results (Table 4) showed that silken tofu made with nigari tended to have higher a* and b* values than that with GDL for both the dry and the soak method while their L* values were similar (P<0.05). This would indicate a light creamy colour for tofu made with nigari, agreeing with those reported in the literature (Khatib et al 2002;Obatolu 2008). The lightness of tofu, L* value, correlated negatively with a* value (r=−0.83, P<0.05) although no significant differences were found between processing methods and coagulants used for L* value or b* value.…”

Effects of soybean protein composition and processing conditions on silken tofu properties

“…In searching for explanations, the literature indicated that many other factors contributed to the texture of tofu. Glycinin (11S) and β‐conglycinin (7S) are the major storage proteins in soybean seeds and their levels vary greatly in soybean varieties . Their contents, ratios (11S/7S), as well as their subunit composition have all been shown to impact on tofu texture.…”

“…Many researchers have attempted to correlate the protein content and the protein subunit composition in soybean seeds with tofu texture, but the results have differed greatly. The levels of the two principal groups of storage proteins in soybean seeds – 11S (glycinin) and 7S (β‐conglycinin) – vary greatly in soybean varieties . For example, the content of 11S and 7S, the ratio of 11S/7S as well as the subunit composition of 11S and 7S have all been shown to impact on tofu texture.…”

Soymilk Viscosity as Influenced by Heating Methods and Soybean Varieties

“…Saxena and Singh (1997) also reported that the viscosity of soymilk made from six soybean varieties varied from 3.8 to 5.2 cP (25C, 60 rpm), and the range of soymilk protein and total solids content was 2.8–3.5% and 5.8–6.5%, respectively. Khatib et al. (2002) reported a large variation in soymilk viscosity among four soybean varieties.…”

“…Saxena and Singh (1997) also reported that the viscosity of soymilk made from six soybean varieties varied from 3.8 to 5.2 cP (25C, 60 rpm), and the range of soymilk protein and total solids content was 2.8-3.5% and 5.8-6.5%, respectively. Khatib et al (2002) reported a large variation in soymilk viscosity among four soybean varieties. They adjusted the total solids content of all soymilk samples to 11.0% (the protein content varied from 4.9 to 5.5% after adjusting), and found that the soymilk viscosity varied from 62 to 157 cP (4C, shear rate: 9.2/s).…”