Liu Zhi-Sheng, Chang K C
Department of Cereal and Food Sciences, North Dakota State University, Fargo, North Dakota 58105, USA.
J Agric Food Chem. 2003 Aug 27;51(18):5214-21. doi: 10.1021/jf034203t.
A rapid titration method was developed for predicting the optimal coagulant concentration for making filled tofu. Cooked soymilk (350 mL, 20 degrees C) in a 400 mL beaker was stirred by a magnetic stirrer to form a swirl. The quick-acting coagulant solution (20.0 Brix) was added into the soymilk at 1.0 mL/min. The swirl depth decreased when the soymilk viscosity increased as a result of increasing the concentration of coagulant in the soymilk. At a suitable stirrer speed, the swirl finally disappeared but the soymilk still maintained rotation, and then the swirl reappeared after around 1 min. The critical point of coagulant concentration (CPCC) was calculated on the basis of the volume of coagulant consumed to get the swirl to disappear. The influences of several factors on the CPCC were investigated, including coagulant addition rate, soymilk temperature, soymilk concentration, soymilk volume, stir bar length, and container size. For validation, 33 soybean samples were used to determine their CPCCs and make filled tofus. The results indicated that CPCC was a characteristic parameter of soymilk and could be used as an effective indicator for predicting optimal coagulant concentration.
开发了一种快速滴定法来预测制作填充豆腐所需的最佳凝固剂浓度。在一个400毫升的烧杯中，用磁力搅拌器搅拌350毫升、20摄氏度的熟豆浆，使其形成漩涡。将速凝剂溶液（20.0波美度）以1.0毫升/分钟的速度加入豆浆中。由于豆浆中凝固剂浓度增加导致豆浆粘度升高时，漩涡深度会降低。在合适的搅拌速度下，漩涡最终消失，但豆浆仍保持旋转，然后大约1分钟后漩涡再次出现。根据使漩涡消失所消耗的凝固剂体积计算凝固剂浓度临界点（CPCC）。研究了几个因素对CPCC的影响，包括凝固剂添加速率、豆浆温度、豆浆浓度、豆浆体积、搅拌棒长度和容器尺寸。为进行验证，使用33个大豆样品来测定它们的CPCC并制作填充豆腐。结果表明，CPCC是豆浆的一个特征参数，可作为预测最佳凝固剂浓度的有效指标。
