Evaluation of Stabilized Soymilk Prepared from Sprouted Soybean with Orange Flesh Sweet Potato Starch for Ambient Storage

Abstract

Ambient storage stability is one of the major constrains amidst drudges of homemade soymilk due to absence of stabilizer there by restricting the consumption to the production areas. Homemade stabilizers and stabilization becomes the only available option. Soymilk prepared from 12 h steeped and 72 h sprouted soybeans was subdivided and each batch stabilized with 0.5%, 1%, 2% and 3% levels of orange flesh sweet potato starches (OFSPS). Functional properties of the starches and proximate, vitamins, minerals, anti-nutrient, physicochemical, and sensory properties of stabilized soymilk samples were assessed with standard analytical methods. With increase in fortification levels, there were significant improvement in ash (0.84 to 0.88%), protein (4.14 to 4.24%), fibre (0.31 to 0.39%), fat (3.75 to 4.19%), carbohydrate (4.54 to 5.55%), vitamins B1 (0.29 to 0.4 mg/100g), B2 (0.10 to 0.14 mg/100g), B3 (1.03 to 1.13 mg/100g), C (0.86 to 1.09 mg/100g) and pro-vitamin A (5.75 to 6.14 µg/100g). Also improved are calcium (26.81 to 28.55 mg/100g), potassium (31.54 to 32.95 mg/100g), magnesium (44.40 to 46.82 mg/100g), sodium (32.73 to 33.43 mg/100g), iron (2.82 to 3.71 mg/100g), saponin (0.028 to 0.035 mg/100g), tannin (0.041 to 0.048 mg/100g), flavonoid (0.031 to 0.034 mg/100g), alkaloid (0.025 to 0.034 mg/100g), phenol (0.25 to 0.34 mg/100g), viscosity (4.89 to 5.60 mg/100g) and specific gravity (1.02 to 1.04 mg/100g). There were decrease in moisture (86.39 to 84.86%), pH (5.75 to 5.45), visible coagulation time (VCT) (28 to 14 d), foam stability (0.51 to 0.00) and general acceptability (6.84 to 4.84). Functional properties of the OFSPS flour were reasonably high. Despite the anti-nutrient increase, all the soymilk samples in this study were safe for human consumption and moderately accepted at maximum stabilization level of 1%.