自然乳酸发酵猪肉蛋白质降解与血管紧张素转化酶抑制肽的分离纯化

Protein Degradation and Purification of ACE Inhibitory Peptides from Pork Naturally Fermented by Lactic Acid Bacteria

对猪肉发酵过程中蛋白质及其降解产物进行分析。结果表明:猪肉在发酵过程中蛋白氮含量随发酵时间延长呈下降趋势,非蛋白氮和氨态氮含量随发酵时间的延长而增加,多肽氮含量呈先升高后降低趋势,在发酵20 d时达最:大值(0.227%);发酵20 d酸肉多肽具有最强的体外血管紧张素转化酶(angiotensin I-converting enzyme,ACE)抑制活性,ACE抑制率达74.35%,IC_(50)为2.75 mg/mL;采用超滤、D101型大孔树脂、葡聚糖凝胶对发酵20 d的酸肉多肽进行分离纯化,分离得到的F3组分有较强的ACE抑制活性,IC_(50)为0.90 mg/mL,肽含量为86.54%,氨基酸组成分析显示水解后增加最多的氨基酸是脯氨酸(7.08倍)和酪氨酸(3.26倍),谷氨酸、组氨酸、天冬氨酸、苯丙氨酸和丙氨酸占全部肽中氨基酸总量的49.09%,构成肽的疏水性氨基酸、芳香族氨基酸和支链氨基酸分别占39.35%、10.69%和13.65%;反相高效液相色谱显示F3组分主要由9个峰组成,有待进一步的纯化。

The contents of protein and its degradation products were analyzed during the natural fermentation of pork by lactic acid bacteria.The results indicated that with the extension of fermentation time,the content of protein nitrogen decreased,non-protein nitrogen and amino acid nitrogen increased,and peptide nitrogen showed a downward trend after an initial increase to the maximum level（226.5 mg/100 g） during fermentation for approximately 20 days.Peptides derived from sour meat fermentation for 20 days exhibited the highest ACE inhibitory activity in vitro.ACE inhibitory rate was74.35%,with an IC_（50） value of 2.75 mg/mL.Ultrafiltration and D101 macroporous resin and gel filtration chromatography were carried out sequentially for the purification of ACE inhibitory peptides.Fraction F3 had a strong ACE inhibitory activity with IC_（50） value of 0.90 mg/mL,and the content of peptides was 86.54%.Amino acid composition analysis showed that most significantly increased levels of amino acids after hydrolysis were observed for prolme（7.08-fold） and tyrosme（3.26-fold）,and glutamic acid,histidine,aspartic acid,phenylalanine and alanine together accounted for 49.09%of the total amino acids in peptides.Hydrophobic amino acids,aromatic amino acids and branched-chain amino acids in peptides accounted for 39.35%,10.69%and 13.65%,respectively.RP-HPLC showed that F3 was mainly composed of nine peaks thus needing further purification.