【作者】 单若兰； 吴昊； 程云辉；

【Author】 Shan Ruolan;Wu Hao;Cheng Yunhui;School of Food & Biological Engineering,Changsha University of Science & Technology;

【机构】 长沙理工大学食品与生物工程学院；

【摘要】 抗冻肽具有保护细胞膜和维持益生菌在低温胁迫下细胞活力的作用,因此,本研究以青稞麸皮蛋白为原料,通过酶解法制备抗冻肽,探究其对鼠李糖乳杆菌ATCC7469的冷冻保护活性及其作用机制。采用碱溶酸沉法提取总蛋白,用6种蛋白酶分别酶解青稞麸皮蛋白,以酶解产物对鼠李糖乳杆菌ATCC7469的冷冻保护活性为评价标准,采用SDS-PAGE凝胶电泳法和高效液相色谱法分别测定总蛋白及6种酶解物的条带分子量范围和蛋白酶解液的分子量分布。结果显示青稞麸皮蛋白的蛋白质浓度为8.94 mg/mL,在-20℃冷冻24 h和48 h后,0.9%无菌生理盐水(阴性对照)的细菌相对存活率分别仅为16.88%和1.79%,而木瓜蛋白酶酶解产物(水解2 h)的细菌冷冻保护活性最高,其相对存活率分别为85.85%和82.03%。凝胶电泳图显示青稞麸皮总蛋白中存在醇溶蛋白(15～110 ku)、谷蛋白(30～50 ku)、清蛋白和球蛋白(11～22 ku)4种条带,而6种酶解产物中这4种条带全部消失,青稞麸皮蛋白均被酶解成分子量小于10 ku的多肽混合物。进一步研究其木瓜蛋白酶酶解产物的分子量分布,发现产物中分子量小于1ku的多肽占比为6.1%,大于3 ku的占比为93.9%。这些结果表明,青稞麸皮抗冻肽可以作为一种潜在的冷冻保护剂用于鼠李糖乳杆菌的保存,为青稞麸皮的利用与开发提供了一种新的途径。更多还原

【Abstract】 Antifreeze peptides(AFPs) possess the ability to protect cell membranes and maintain the viability of probiotics under low-temperature stress.Therefore,this study utilized highland barley bran protein as the raw material to prepare antifreeze peptides through enzymatic hydrolysis,aiming to investigate their cryoprotective activity on Lactobacillus rhamnosus ATCC7469 and explore the underlying mechanism.Total protein was extracted using the alkali-soluble acid precipitation method.The barley bran protein was hydrolyzed with six different proteases,and the cryoprotective activity of the hydrolysates on L.rhamnosus ATCC7469 was used as the evaluation criterion.SDS-PAGE and high-performance liquid chromatography(HPLC) were employed to determine the molecular weight ranges of the total protein and the six hydrolysates,as well as the molecular weight distribution of the protease hydrolysates.The results showed that the protein concentration of highland barley bran protein was 8.94 mg/mL.After freezing at-20℃ for 24 h and 48 h,the relative survival rates of bacteria in 0.9%sterile physiological saline(negative control) were only 16.88% and 1.79%,respectively.In contrast,the papain hydrolysate(2 h hydrolysis) exhibited the highest cryoprotective activity,with relative survival rates of 85.85% and 82.03%,respectively.The SDS-PAGE results indicated the presence of four bands in the total protein of highland barley bran,corresponding to prolamin(15-110 ku),glutelin(30-50 ku),albumin,and globulin(11-22 ku).However,these bands disappeared in all six hydrolysates,indicating that the barley bran protein was hydrolyzed into peptide mixtures with molecular weights below 10 ku.Further analysis of the molecular weight distribution of the papain hydrolysate revealed that 6.1% of the peptides had a molecular weight below 1 ku,while 93.9% were above 3 ku.These results demonstrate that highland barley bran-derived antifreeze peptides can serve as potential cryoprotectants for the preservation of L.rhamnosus,offering a new approach for the utilization and development of highland barley bran.更多还原