基于模拟胃肠道消化的云南民族乳制品蛋白肽研究

Characterization of Peptides from Simulated Gastrointestinal Digestion of Ethnic Dairy Products in Yunnan,China

乳扇、乳饼和奶渣是云南民族传统乳制品,具有历史悠久、特色鲜明、蛋白质含量高等特点。本研究基于模拟胃肠道消化,采用液相色谱-串联质谱、氨基酸分析仪研究乳扇、乳饼和奶渣的肽谱及游离氨基酸含量,并借助蛋白肽数据库分析潜在的生物活性肽。结果表明,乳扇蛋白肽221条,分子质量集中在500~750 Da,潜在的功能活性肽包括血管紧张素转化酶抑制肽5条、免疫调节肽4条、抗氧化肽3条,抗血栓肽2条和抗菌肽1条。乳饼蛋白肽225条,分子质量集中在750~1000 Da,功能活性肽包括抗氧化肽2条。奶渣蛋白肽222条,分子质量集中在750~1000 Da,功能活性肽包括免疫调节肽2条、抗氧化肽2条和抗血栓肽1条。3种乳制品中的蛋白肽主要源于β-和α-酪蛋白。乳扇、乳饼和奶渣经模拟消化液消化后其游离氨基酸含量分别为9.45、10.7 g/100 g和9 g/100 g,其中,中性氨基酸含量最高,其次依次为碱性氨基酸和酸性氨基酸。本研究揭示了乳扇、乳饼和奶渣的生物学价值,可为功能活性产品的研发提供科学依据。

Dairy fan,milk pastry and milk residue as traditional ethnic dairy products in Yunnan have a long history,possess distinctive characteristics and are high in protein.This study was implemented to investigate the peptide profiles and free amino acid contents of dairy fan,milk pastry and milk residue by liquid chromatography-tandem mass spectrometry(LC-MS/MS)and an amino acid analyzer based on simulated gastrointestinal digestion,and to analyze potential biological peptides by peptide database searching.The results showed that a total of 221 peptides including five angiotensin converting enzyme inhibitory peptides,four immunoregulatory peptides,three antioxidant peptides,two antithrombotic peptides and one antibacterial peptide were identified from dairy fan,with molecular mass distribution in the range of 500–750 Da.In total 225 peptides including two potential antioxidant peptides were identified from milk pastry,with molecular mass distribution in the range of 750–1000 Da.In total 222 peptides including two immunoregulatory peptides,two antioxidant peptides and one antithrombotic peptide were identified from milk residue with molecular mass distribution in the range of 750–1000 Da.The peptides in the three dairy products were mainly derived fromβ-andα-casein.The contents of free amino acids in dairy fan,milk pastry and milk residue after simulated gastrointestinal digestion were 9.45,10.7 and 9 g/100 g,respectively,with neutral amino acids being the most abundant,followed by basic and acidic amino acids.This study reveals the biological value of dairy fan,milk pastry and milk residue,and provides a scientific basis for the development of functional dairy products.