限制性酶解修饰对郁李仁分离蛋白结构和功能特性的影响

Effects of Restrictive Enzymatic Hydrolysis Modification on Structure and Functional Properties of Plum Seed Protein Isolates

  • 摘要:
      目的  以郁李仁分离蛋白为研究对象, 探讨限制性酶解修饰对郁李仁蛋白结构和功能特性的影响。
      方法  采用碱性蛋白酶修饰郁李仁分离蛋白, 探讨酶解时间对郁李仁分离蛋白亚基组成、二级结构、三级结构、溶解性、乳化性、ζ-电势、表面疏水性以及热稳定性的影响。
      结果  郁李仁分离蛋白经过酶解修饰后, 其溶解性提高了156%, 乳化活性提高了135%, 乳化稳定性提高了696%, 表面疏水性提高了182%。这些功能特性的改善主要是因为酶解修饰诱导郁李仁分离蛋白质中小分子肽链的释放、无规则卷曲结构的增加、分子的去折叠化以及表面电荷数量的增加。然而, 郁李仁分离蛋白功能特性的改善与水解度密切相关。过度水解(水解度>6.3)会诱导蛋白质发生聚集行为, 从而导致功能特性的下降。此外, 酶解修饰还会降低郁李仁分离蛋白的热稳定性。
      结论  在采用限制性酶解修饰技术时, 可以通过控制水解度, 从而改善郁李仁分离蛋白的功能特性。

     

    Abstract:
      OBJECTIVE  To explore the effects of restrictive enzymatic modification on the structural and functional characteristics of plum seed protein, using the plum seed protein isolates as the research object.
      METHODS  The alcalase was used to hydrolyze plum seed protein isolates. The effects of hydrolysis time on subunits, secondary and tertiary structure, solubility, emulsifying properties, surface hydrophobicity, ζ-potential and thermal stability of protein were evaluated.
      RESULTS  After enzymatic modification of plum seed protein isolates, the solubility, emulsifying activity index, emulsifying stability and surface hydrophobicity were improved by 156%, 135%, 696%, and 182%, respectively. The improvement in functional properties was attributed to the release of small molecular peptide, the increase of random coil and surface charge and unfolding of molecule induced by enzymatic modification. However, the improvement in functional properties was also dependent on the degree of hydrolysis. The excessive hydrolysis (the degree of hydrolysis > 6.3) could induce the aggregation of protein which led to a decrease in functional properties. In addition, the treatment of limited hydrolysis also reduced the thermal stability of plum seed protein isolates.
      CONCLUSION  The functional properties of plum seed protein isolates can be improved by controlling the degree of hydrolysis.

     

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