Investigation into the Coagulating Properties of Acid and Enzyme Coagulated Soy Protein Precipitate

Abstract

Precipitation is widely used in processing of biological products, such as proteins. The coagulating properties of Sodom apple ju ice, vinegar, lemon juice and rennet as coagulants of soy protein precipitate fro m soymilk at different temperature were investigated. Soymilk was produced using the hot grind method. The studied coagulants were used to precipitate soy protein fro m the produced milk at d ifferent temperature respectively. The coagulation time was observed to decrease with increasing temperature, with 100℃ giv ing the best time. The p H of the coagulated proteins was observed to decrease with increasing temperature with the optimal pH observed at 70℃ for all the coagulants. No significant difference was observed on the effect of coagulating temperatures on the yield of coagulated soy protein precipitate. Results fro m this study indicate that optimu m coagulating activ ities can be achieved between 70- 80℃. Ho wever, the yields by the studied coagulants are not affected by temperature. Thus, imp lying that temperature modulate the coagulating activit ies, pH and not yields of the coagulants. Therefore, production at 70 - 80℃ will g ive the best soy protein quality.