CONTINUOUS PRODUCTION OF HIGH-DEGREE CASEIN HYDROLYSATES BY IMMOBILIZED PROTEASES IN COLUMN REACTOR

The enzymatic complete hydrolysis of casein was investigated by using immobilized endopeptidase and exopeptidase packed in the jacketed colu mn reactors. The mass transfer efficiency of proteins was improved by using sliced shrimp chitin hull as enzyme support, which formed a netw ork structure inside the column reactor that prevented the formation o f protein precipitate and increased the line flow rate of protein solu tion. The specificity of the protease was of crucial importance for bo th the hydrolysis degree and the free amino acid content of the hydrol ysates. Of the enzymes tested, the immobilized A. oryzae protease was the most effective enzyme in breaking down the casein molecules and re leasing the free amino acid from casein hydrolysates. The immobilized pancreatic and kidney exopeptidase could lead to a 20% increase of fre e amino acids. The free amino acid content of casein hydrolysates was 34.81% after processing and could reach to 64% if the column length wa s doubled, but 100% hydrolysis was impossible as the reverse reaction was also taking place. The casein hydrolysates was characterized by it s high degree of hydrolysis and high content of free amino acids. It c an be applied in infant formula, element diet, and as a protein ingred ient for food industry.