食品科学 ›› 2019, Vol. 40 ›› Issue (23): 123-129.doi: 10.7506/spkx1002-6630-20181101-013

• 食品工程 • 上一篇    下一篇

超声处理对牛乳酪蛋白结构及抗原性的影响

薛海燕,操歌,贺宝元,樊娇娇,薛丽欢   

  1. (1.陕西科技大学食品与生物工程学院,陕西 西安 710021;2.陕西科技大学轻工科学与工程学院,陕西 西安 710021)
  • 出版日期:2019-12-15 发布日期:2019-12-24
  • 基金资助:
    国家自然科学基金青年科学基金项目(31301405);陕西省科技统筹计划项目(2013KTZB02-05(2)); 陕西省教育厅服务地方专项项目(19JC05);西安市科技计划农业科技创新工程项目(20193035YF023NS023)

Effect of Ultrasonic Treatment on the Structure and Antigenicity of Bovine Caseins

XUE Haiyan, CAO Ge, HE Baoyuan, FAN Jiaojiao, XUE Lihuan   

  1. (1. School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi’an 710021, China;2. College of Bioresources Chemical and Materials Engineering, Shaanxi University of Science and Technology, Xi’an 710021, China)
  • Online:2019-12-15 Published:2019-12-24

摘要: 利用超声波处理牛乳致敏蛋白α-酪蛋白(casein,CN)和β-CN,结合十二烷基硫酸钠-聚丙烯酰胺凝胶电泳、圆二色光谱、荧光光谱及酶联免疫吸附测定等方法分析α-CN和β-CN结构和抗原性的变化。结果表明:随着超声波功率的增大,α-CN的分子质量无显著性变化,β-CN在600 W时发生聚集,两种酪蛋白羰基含量上升,自由巯基含量先下降后回升,在500 W时达到最低,疏水性则呈现与自由巯基含量相反的规律;二级结构中,α-螺旋结构经超声处理后其相对含量减少,无规卷曲相对含量随着超声功率先增加后降低,功率为500 W时相对含量最高,β-折叠的相对含量变化趋势则与无规卷曲相反,这表明超声波处理破坏了酪蛋白的高级结构;随着超声功率的增强,抗原性呈现先升高后降低的趋势,其中500 W时抗原性最高,与酪蛋白疏水性及无规卷曲结构相对含量呈正相关,与β-折叠结构的相对含量呈现负相关。超声处理酪蛋白在影响蛋白构象及结构的同时改变其抗原性,且抗原性与疏水性及无规卷曲相对含量相关。

关键词: 牛乳酪蛋白, 超声波, 抗原性, 羰基, 巯基, 二级结构, 疏水性

Abstract: In this study, changes in the structure and antigenicity of the milk allergenic proteins α-casein (α-CN) and β-casein (β-CN) after ultrasonic treatment were investigated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, circular dichroism (CD) spectroscopy, fluorescence spectroscopy and enzyme-linked immunosorbent assay (ELISA). The results showed that with the increase of ultrasonic power, the molecular mass of α-CN did not change significantly, β-CN aggregated at 600 W; the carbonyl contents of the two caseins increased, and the free sulfhydryl contents decreased first and then rose after reaching a minimum value at 500 W, while the trend was opposite to that of hydrophobicity. The proportion of α-helical secondary structure was reduced after sonication, and the proportion of random coil initially increased with ultrasonic power up to 500 W and then decreased; this trend was opposite to that of β-sheet content, indicating that ultrasonic treatment could destroy the structure of casein. As the ultrasonic power increased, the antigenicity first increased, reaching a maximum level at 500 W, and then decreased. The hydrophobicity of caseins was positively correlated with changes in random coil content, but negatively correlated with changes in β-sheet content. Sonication could affect protein structure conformation while altering the antigenicity of caseins, which was associated with changes in hydrophobicity and random coil content.

Key words: bovine α-casein, ultrasonic, antigenicity, carbonyl, sulfhydryl, secondary structure, hydrophobicity

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