食品科学

• 生物工程 • 上一篇    下一篇

牦牛乳硬质干酪苦味肽的分离与特征鉴定

宋雪梅1,2,张 炎1,2,杨 敏2,3,梁 琪1,2,*   

  1. 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
  • 出版日期:2016-08-15 发布日期:2016-08-30

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

SONG Xuemei1,2, ZHANG Yan1,2, YANG Min2,3, LIANG Qi1,2,*   

  1. 1. College of Food Science and Engineering, Gansu Agricultural University, Lanzhou 730070, China;
    2. Functional Dairy Product Engineering Laboratory of Gansu, Lanzhou 730070, China;
    3. College of Science, Gansu Agricultural University, Lanzhou 730070, China
  • Online:2016-08-15 Published:2016-08-30

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。

关键词: 牦牛乳硬质干酪, 苦味肽, 特征, &beta, -酪蛋白

Abstract:

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.

Key words: hard cheese made from yak milk, bitter peptide, characteristic, β-casein

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