酸碱处理对酪蛋白源ACE抑制肽稳定性影响的研究

Study on effects of treatment of heating combined with acid and alkali on the stabilities of angiotensin converting enzyme inhibitory peptide derived from bovine casein

在不同pH值条件下,处理酪蛋白源ACE(血管紧张素转换酶)抑制肽,以ACE抑制活性、游离氨基质量浓度以及色差值为检测指标,研究了酸碱处理对ACE抑制肽稳定性的影响。结果表明,ACE抑制肽受酸碱度影响较大,pH值为1~8的ACE抑制肽的抑制活性维持在一个较高水平,平均抑制活性达到58.33%,pH值为9~13的样品抑制活性明显降低;游离氨基质量浓度在中性条件下较高,随着酸性和碱性条件的增强,其含量逐渐降低;另外,ACE抑制肽在pH<3和pH>11条件下,随酸性和碱性条件的增强,b*值变大,颜色变深。因此,在食品加工贮藏过程中,为使酪蛋白源ACE抑制肽保持活性稳定,应避免其处于过酸或过碱的加工条件。

Effects of different processing and storage conditions on stabilities of angiotensin converting enzyme inhibitory peptide were studied by determining ACE inhibitory activity, free amino group content and color. It was shown that stabilities of ACE inhibitory peptide were easi- ly influenced by pH value. Under the conditions of pHI^pH8, ACE inhibitory activity maintained in a higher level and average inhibition ac- tivity reached 58.33%. Meanwhile, there was decrease of ACE inhibitory activity at pH9-pH13. Under the conditions of pH〈3 and pH〉9, free amino group content of ACE inhibitory peptides decreased and their colors turned dark. Consequently, in order to keep the stabilities of ACE inhibitory peptide stable, food processing and storage conditions ofpH〈3 or pH〉9 should be avoided.