牦牛乳硬质干酪苦味肽的分离与特征鉴定  

Separation and Characterization of Bitter Peptides from Hard Cheese Made from Yak Milk

作　　者：宋雪梅[1,2] 张炎[1,2] 杨敏[2,3] 梁琪[1,2] 

机构地区：[1]甘肃农业大学食品科学与工程学院,甘肃兰州730070 [2]甘肃省功能乳品工程实验室,甘肃兰州730070 [3]甘肃农业大学理学院,甘肃兰州730070

出　　处：《食品科学》2016年第15期160-164,共5页Food Science

基　　金：国家自然科学基金地区科学基金项目(31260383)

摘　　要：为了探究牦牛乳硬质干酪中苦味肽组成特征,采用氯仿-甲醇法提取苦味肽,通过Sephadex G-25葡聚糖凝胶色谱进行分离纯化,并利用液相色谱-串联质谱（liquid chromatography-mass spectrometry/mass spectrometry,LC-MS/MS）对其分离的苦味较强组分进行特征鉴定。结果表明：经Sephadex G-25葡聚糖凝胶色谱分离得到3个不同分子质量的组分,组分Ⅱ具有明显苦味。LC-MS/MS鉴定出组分Ⅱ中存在14种苦味肽,主要为氨基酸残基数目7~17个、分子质量小于2 000 D的小肽,苦味肽序列中存在的疏水性氨基酸主要有脯氨酸、缬氨酸、亮氨酸、苯丙氨酸、异亮氨酸,800~1 500 D苦味肽占64.29%,源自β-酪蛋白（β-casein,β-CN）降解产物的苦味肽占92.86%。因此,干酪成熟过程中源自β-CN的具有较强疏水性、分子质量小于2 000 D的混合多肽的积累可能对干酪苦味的产生有较大影响。The intention of this work was to investigate the structural characteristics of bitter peptides in hard cheese madefrom yak milk. Bitter peptides were extracted with chloroform-methanol mixture and isolated by using gel chromatography,and the more bitter fractions were identified by liquid chromatography-mass spectrometry （LC-MS-MS）. The results showedthat three fractions named as fractions I, II and III were obtained through Sephadex G-25 column chromatography andfraction II tasted the most bitter among these and had a flavor described as slightly bitter. Fourteen peptides were identifiedin fraction II and these peptides were composed of 7–17 amino acid residues in a molecular weight range less than 2 000 D.Hydrophobic amino acids such as proline, valine, leucine, phenylalanine and isoleucine constituted these bitter peptides. Thebitter peptides in a molecular weight range of 800 –1 500 D accounted for 64.29% and bitter peptides derived from β-casein（β-CN） accounted for 92.86%. Therefore, polypeptides derived from β-casein with high hydrophobicity and molecularweight below 2 000 D may have a significant influence on the bitterness of cheese.

关 键 词：牦牛乳硬质干酪 苦味肽 特征 Β-酪蛋白 

分 类 号：TS252.1[轻工技术与工程—农产品加工及贮藏工程]