Color, texture, nutrient contents, and sensory values of vegetable soybeans [Glycine max (L.) Merrill] as affected by blanching

摘要

Vegetable soybeans (VSB) are harvested over a short period of the year as they are in the immature state outside that period. Freezing and storing, after blanching, constitute a possible method to commercialize vegetable soybeans. In this study, blanching conditions of vegetable soybeans [Glycine max (L.) Merrill] were determined, based on colour, texture, nutrient content, and sensory value. The sensory values (a seven-point scale) for the overall qualities of VSB blanched at 80 ℃ for 30 min, 90 ℃ for 20 min, and 100 ℃ for 10 min were 4.6, 5.0 and 5.2, respectively. These three conditions gave the highest sensory values at each temperature, and were used for further examination. The levels of greenness degradation at the three blanching conditions were similar. The loss of nutritive components including sugars, vitamins B_1, B_2, and C, were minimal at 100 ℃ for 10 min. Seed hardness values (g_f), after blanching, were 469, 392, and 284, respectively, whereas that of the control was 576. Conclusively, blanching at a high temperature and short time is recommended.