食品科学

• 基础研究 • 上一篇    下一篇

芋艿分离蛋白的理化性质

黄友如,王教飞,朱东兴,李昕蓓,徐田甜   

  1. 常熟理工学院生物与食品工程学院,江苏 常熟 215500
  • 出版日期:2016-08-15 发布日期:2016-08-30

Physicochemical Characterization of Taro Protein Isolates

HUANG Youru, WANG Jiaofei, ZHU Dongxing, LI Xinbei, XU Tiantian   

  1. School of Biological Science and Food Engineering, Changshu Institute of Technology, Changshu 215500, China
  • Online:2016-08-15 Published:2016-08-30

摘要:

针对芋艿分离蛋白的等电点、变性温度、氨基酸组成及亚基分子质量分布等重要理化性质进行研究。结果表明,芋艿分离蛋白各组分的等电点主要集中在pI值为6.73和5.21两个条带,分别占分离蛋白总量的16.36%和27.30%;十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(sodium dodecyl sulfate-polyacrylamide gel electrophoresis,SDS-PAGE)分析表明芋艿分离蛋白主要由4 种亚基组成,其分子质量分别分布在57 000、46 300、34 200、8 500 D左右,添加巯基乙醇可增加分子质量在23 100 D左右的条带,证明芋艿分离蛋白亚基间有二硫键的交联;差示扫描量热(differential scanning calorimetry,DSC)分析确定芋艿分离蛋白的变性温度为(71.3±0.2) ℃,变性焓ΔH为1.550 J/g;氨基酸组成分析表明,非极性氨基酸含量占37.26%,极性氨基酸含量占62.74%;必需氨基酸(色氨酸除外)含量占39.02%,幼儿所必需的半必需氨基酸(即精氨酸、组氨酸)含量占9.9%。

关键词: 芋艿分离蛋白, 等电点, 变性温度, 氨基酸组成, 分子质量

Abstract:

Isoelectric point (pI), denaturation temperature, amino acid composition, and molecular weight of taro protein
isolates were studied in this research. The results showed taro protein isolates had two main pI bands near 6.73 and
5.21, accounting for 16.36% and 27.30% of the total proteins, respesctively. Sodium dodecyl sulfate-polyacrylamide gel
electrophoresis (SDS-PAGE) analysis indicated that taro protein isolates were mainly composed of four subunits with
relative molecular weights distributed around 57 000, 46 300, 34 200 and 8 500 D. A new band having a molecular weight
of about 23 100 D appeared with added mercaptoethanol suggesting that taro protein isolates had disulfide bonds between
subunits. Differential scanning calorimetry (DSC) analysis confirmed that denaturation temperature of taro protein isolates
was (71.3 ± 0.2) ℃ with an enthalpy change (ΔH) of 1.550 J/g. Amino acid analysis demonstrated that the contents of
non-polar and polar amino acids were 37.26% and 62.74%, respectively. The content of essential amino acids except for
tryptophan was 39.02% and the content of semi-essential amino acids for very young children was 9.9%.

Key words: taro protein isolates, isoelectric point, denaturation temperature, amino acid composition, molecular weight

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