Optimization of the biological processing of rice dregs into nutritional peptides with the aid of trypsin.

Abstract

A protein hydrolysate was prepared from rice dregs (RD) using trypsin as a suitable protease. The hydrolysis conditions were optimized with response surface methodology, and then a mathematical model was developed to demonstrate the effect of each process parameter on the degree of hydrolysis (DH) and recovery of protein (RP). A hydrolysate with relatively high RP (75.81%) and low DH (6.95) was obtained from RD by hydrolyzing for 2.4h at pH7.6 52.8°C with a enzyme/RD ratio of 0.89:1000 (w/w) and RD/water level of 0.22g/mL. The dried hydrolysate was low molecular weight peptides (predominantly <1,000Da) and it possessed good solubility at various pH levels. Result of amino acid analysis revealed that the hydrolysate was considerably enriched in essential amino acids. Thus, the protein hydrolysate has a potential to be an excellent protein ingredient as a balanced milk replacer.