Abstract:

Defatted rapeseed meal was hydrolyzed with alcalase firstly and then with neutral protease to prepare compound amino acids and peptides. The two hydrolysis processes were optimized by orthogonal test with hydrolysis degree with investigation index. Moreover, the functional properties of the obtained hydrolysates were discussed. The results showed that the optimal conditions of alcalase hydrolysis were as follows: pH value 10.5, liquid to solid ratio 15:1, temperature 50 ℃, time 1.5 h, and enzyme dose 3250 U/g of substrate, and those of neutral protease hydrolysis were as follows: pH 9, temperature 45
℃, time 2 h, and enzyme dose 3250 U/g of substrate. Under the above conditions, the hydrolysis degree and nitrogen yield were 25.66% and 86.8%, respectively. In the range of pH 3 to 7, the nitrogen soluble index (NSI) of the obtained hydrolysates was higher than 72.19%. Their trichloroacetic acid (TCA)-NSI was 85.67%. Through hydrolysis, the contents of tannin, glucosinolate and phytic acid in defatted repeseed meal were decreased markedly .

Key words: defatted rapeseed meal, compound amino acids, alcalase, neutral protease