Studies on the enzymatic hydrolysis of rice protein using commercial enzymes in batch reactor
S. Abd Aziz* and L.O. Gaik Ai
Biotechnology Department, Faculty of Food Science and Biotechnology, University Putra Malaysia, 43400 Serdang, Selangor, Malaysia
Received 13 July 2000 / Accepted 15 September 2000
Abstract.
Studies on the enzymatic hydrolysis of the rice protein (Oryza sativa Basmati) by two commercial enzymes, Flavourzyme and Alcalase, have been investigated. To understand the process variable involved in producing hydrolytic products from rice protein, the estimation of degree of hydrolysis was determined by measurement of free amino groups and by proton release method. These studies have shown that the degree of hydrolysis of rice protein was controlled by temperature, substrate concentrations, the type of enzyme used and enzyme concentrations. The pKa for Flavourzyme and Alcalase were 5.43 and 6.07, respectively. The results show that the suitable hydrolysis condition for Flavourzyme were 4% substrate concentration, 150 mg/mI enzyme concentration, pH 8.0 and at optimum temperature of 55oC. While for Alcalase the suitable hydrolysis condition for Alcalase were 4% substrate concentration, 200 mg/ml enzyme concentration, pH 8.0 and at optimum temperature of 60oC. The enzyme decay determination were also done to each of the enzyme used and it was found that at optimum operating temperature, the half life for Flavourzyme and Alcalase were 15.42 min and 11.25 min, respectively.
Keywords: Enzymatic hydrolysis, pH stat method, protein hydrolysate, rice protein
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