Process Optimization of Tempeh Protein Isolate from Soybean (Glycine max Merr) and Cowpea (Vigna unguiculata) Mixture

Abstract

Production of ‘tempeh’ (fermented soybean) protein isolates in Indonesia is still very low. It is necessary to increase the production with the alternative materials which is make by soybean and cowpea mixture. The utilization of this soybean cake (tempeh) as protein isolate raw material is expecting benefits both of soybean and cowpea component which can complement each other. Protein’s content of protein isolates should be a minimum of 90% (db). Therefore, it is necessary to find the precipitation pH and the optimum level of purification in order to get tempeh protein isolate with high protein content. The analytical method used descriptive analysis. The optimal process of tempeh protein isolates from soybean and cowpea mixture conducted with pH 5 and pH 4 precipitation, the oil extraction was carried out at the beginning of the process (before extraction of protein) and before the drying stage. The result showed that the tempeh protein isolate of soybean and cowpea mixing have 75.12% (db) protein content. It was increasing in 20.67% to 50.16% from previous research.