单 位：
甘肃省功能乳品工程实验室;甘肃农业大学食品科学与工程学院
关键词：
牦牛乳硬质干酪;苦味肽;特征;β-酪蛋白
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。
译 名：
Separation and Characterization of Bitter Peptides from Hard Cheese Made from Yak Milk
作 者：
SONG Xuemei;ZHANG Yan;YANG Min;LIANG Qi;College of Food Science and Engineering, Gansu Agricultural University;Functional Dairy Product Engineering Laboratory of Gansu;College of Science, Gansu Agricultural University;
关键词：
hard cheese made from yak milk;;bitter peptide;;characteristic;;β-casein
摘 要：
The intention of this work was to investigate the structural characteristics of bitter peptides in hard cheese made from 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 showed that three fractions named as fractions I, II and III were obtained through Sephadex G-25 column chromatography and fraction II tasted the most bitter among these and had a flavor described as slightly bitter. Fourteen peptides were identified in 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. The bitter 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 molecular weight below 2 000 D may have a significant influence on the bitterness of cheese.
