104C-25 |
The influence of soybean storage conditions on the quality and yield of soymilk and tofu |
M. F. SUSANTO, Food Science and Human Nutrition, Iowa State University, 2312 Food Science, Ames, IA 50011 and L. A. Wilson, Dept. of Food Science & Human Nutrition, Iowa State Univ., 2541 Food Science Bldg., Ames, IA 50011-1061. There is an increase in soybean consumption in United States because of its health benefit for reducing risk of chronic diseases like heart disease. During soybean storage, biological, chemical, and physical changes occur, dependent on different storage time, temperature, and humidity. These changes might lead to quality and yield reduction of soybean products. The objective of this study is to determine the influence of room, refrigeration, and frozen temperatures in dry and presoaked conditions on soybean properties, and the yield of soymilk and tofu. These results could be used to optimize the storage condition for soybeans on earth and in NASA missions. Soybeans were stored for 8 months at: dry at -20ºC, 4ºC, 25º C, and wet at -20ºC, analyzed at 0, 2, 6, and 8 months, and processed into soymilk and tofu (steam-jacketed kettle and tofu press). Water absorption of soybean, yield, moisture, protein, color, ºbrix and viscosity of soymilk, and texture of tofu were determined. Soymilk soluble solids, viscosity, yield, and % protein; tofu yield and % protein; and soybean water absorption did not change during storage. The moisture percentage of soymilk and tofu for all treatments increased and stayed constant after 2 month of soybean storage. Increases in greenness and redness were observed in the soymilk and tofu respectively. The tofu firmness decreased slightly at 2 months, and increased up to 6 month. To maintain tofu firmness, extra coagulant and coagulation time were necessary. The treatments used in this study were able to maintain the soybean products quality and yield up to 8 months of soybean storage. Further studies with longer storage time at higher temperatures and humidity are needed to further define the influence of commercial soybean storage conditions on the quality of soybean products.
Session 104C, Fruit & Vegetable Products: Vegetables (Processed)
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