酶解机械预处理啤酒糟制备饲用蛋白肽

Study on enzymatic hydrolysis and ball milling of brewer's spent grain for feed protein peptide

啤酒糟经过粉碎后筛分,筛下物经球磨后粗蛋白含量提高到38.8%,比原样提高了36.1%,水溶性蛋白含量提高到2.53%,比原样提高了3.1倍,经中性蛋白酶液态酶解,水溶性蛋白含量达到12.85%,比原样的7.88%提高了1.6倍,机械预处理显著提高了酶解效率。通过单因素实验和混合水平均匀设计实验,确定了啤酒糟最优酶解条件:加酶量2 400 U/g,酶解温度45℃,酶解pH 8.0,酶解时间8 h,此时水溶性蛋白含量能够达到21.31%,提取率达到54.9%。对酶解液进行真空冷冻干燥,制备饲用蛋白肽,粗蛋白含量达到78.8%,氨基酸含量达到74.6%,必需氨基酸含量达到28.18%,多肽含量达到60.8%。

After blade grinding and screening pretreatment, the undersize brewer＇ s spent grain was dealt with ball milling. Consequently, the content of crude protein was increased up to 38.8% , which was 36.1% higher than that in origin sample, while the content of soluble protein was up to 2.53% , which was 3.1 times higher than that in origin sample. The soluble protein content of undersize brewer＇ s spent grain was increased up to 12.85% after the enzymatic hydrolysis of neutral protease, which was 1.6 times higher than that in origin sample （7.88%）. The re- sults showed that the efficiency of enzyme hydrolysis had been significantly improved by mechanical pretreatment. The enzyme hydrolysis conditions were optimized by single factor experiment and uniform design. The optimal conditions were as follows ： the dosage of enzyme of 2400 U/g, enzyme hydrolysis temperature of 45℃ , enzyme hydrolysis pH of 8.0, and enzyme hydrolysis time of 8 h. Under these conditions, the content of soluble protein was up to 21.31%. The exaction rate was up to 54.9%. The hydrolysis liquid was dealt with vacuum freeze drying to prepare feed protein peptide. The crude protein content of feed protein peptide was up to 78.8%. The amino acids content was increased to 74.6%. Essential amino acids content was 28.18% , and polypeptides content was 60.8%.