| Summary: | 碩士 === 中國文化大學 === 生活應用科學研究所 === 98 === This research uses Canada soybean as the raw materials. There were three purposes in this research, the first purpose is going to build up the alkaline solution absorption models of soybeans. The other purposes are going to find out the effect of different soaking and grinding conditions on (1) the total bacteria counts of the soaking water and raw soymilk and (2) the quality of raw soymilk and tofu.
The result showed that all of the absorption rate, solid dissolving rate and constant of hydration rate of soybean were increased by temperature increasing, pH increasing and soaking time elongated. The pH of the soaking water increased from pH7.0 to pH11.0 could reduced the soybean’s soaking time and reduced the activation energy of the soaking model from 24.63 KJ/mol to 20.43 KJ/mol. Soybean soaked in pH8.0 solution had the lowest total bacteria counts（2.24 log CFU/g）of soaking water which were compared with soybean soaked by pH7.0 and pH9.0 solutions. Meanwhile, the soybean soaked in 65℃ solution had the lowest total bacteria count（1.45 log CFU/g）of soaking water which were compared with soybean soaked by 5℃ and 30℃ solutions. Increasing the water change times could reduced the total bacteria counts of soaking water. The raw soymilk made by the condition of 5℃ water soaking and 5℃ water grinding had the lowest total bacteria counts. The soymilk turned more yellowish and greenish when the grinding water temperature increased from 5℃ to 80℃. Soymilk ground with 5℃ water had the highest L-value, white index, viscosity, protein recovery and solid recovery which were compared with soybean ground by 30℃ and 80℃ water. The tofu which made by the soymilk ground with 5℃ water had the highest density, hardness, adhesiveness, gumminess, chewiness, springiness cohesiveness and lowest syneresis rate which were compared with the tofu’s made by the soymilk ground with 30℃ and 80℃ water. These results can provide the soybean processors to improve the quality of the soaking and grinding conditions of the soy products.
|
|---|
