醋制对黑豆蛋白含量及多肽ACE抑制活性的影响

Effect of Vinegar Soaking on Black Soybean Protein Fractions Content and Their Corresponding Peptides' ACE Inhibitory Activity

为考察醋制对黑豆蛋白含量及多肽ACE抑制活性的影响,为对黑豆醋浸过程中蛋白组分及含量变化进行分析,并对相应ACE抑制肽活性进行测定。黑豆经醋浸不同时间后,采用顺序抽提法提取清蛋白、球蛋白、醇溶蛋白和谷蛋白,并采用凯氏定氮法及SDS-PAGE电泳进行定量和定性分析;各蛋白组分经胃蛋白酶水解,经超滤(截留分子量3 k D)后收集滤液,获得多肽组分,RP-HPLC法进行ACE抑制活性评价。结果表明:经醋浸14 d后,黑豆总蛋白含量变化幅度小于±0.5%;清蛋白含量由55.13%(0 d)降低至9.61%(14 d);球蛋白由7.04%(0 d)增加到20.34%(14 d);醇溶蛋白由0.81%(0 d)增加到1.72(14 d);谷蛋白由21.11%(0 d)增加到59.45%(14 d),含量最高。醋浸处理降低了清蛋白源多肽的ACE抑制活性,但提高了球蛋白、醇溶蛋白及谷蛋白多肽的ACE抑制活性,其中,谷蛋白多肽抑制率由18.18%(0 d)增加至37.58%(14 d),抑制活性升高。醋浸可改变黑豆各蛋白组分的含量和对应多肽的ACE抑制活性,其中,谷蛋白含量及其多肽ACE抑制活性均有增加。研究结果表明可进一步采用分离纯化技术从谷蛋白多肽中获得高活性降压肽。

To analyze the variation total protein content and four protein fractions of black soybean and their corresponding peptides＇ ACE inhibitory activity after soaking in vinegar,four protein fractions of albumin,gulbulin,prolamin and glutelin were sequentially extracted and then protein contents and molecular weight distribution were measured by Kjeldah method and Tris-Glycine SDS-PAGE,respectively.These four protein fractions were hydrolyzed by pepsin and the hydrolysate was passed through an ultrafiltration membrane（cutting off molecular weight of 3 kD） to collect the ultrafiltrate.The angiotensin I converting enzyme（ACE） inhibitory activity of the peptides was evaluated by RP-HPLC.The results showed that：The total protein content of black soybean changed less than ±0.5% after soaking in vinegar for 14 d,while the content of albumin reduced from 55.13%（0 d） to 9.61%（14 d）,globulin,prolamin and glutelin contents increased from 7.04%（0 d） to 20.34%（14 d）,0.81%（0 d） to 1.72%（14 d） and 21.11%（0 d） to 59.45 %（14 d）,respectively.Vinegar soaking made the ACE inhibitory activity of albumin peptides decreased,while those from gulbulin,prolamin and glutelin increased.Among them,glutelin peptides manifested highest increased inhibitory activity from 18.18%（0 d） to 37.58%（14 d）.The protein fraction contents of black soybean and ACE inhibitory activity of corresponding peptides significantly changed after vinegar soaking,among them,glutelin content and its peptide ACE inhibitory activity were increased,suggested that the antihypertensive peptides could be further generated from glutelin peptide by using the technology of separation and purification.