酪蛋白胃肠模拟水解液活性检测及细胞吸收机制初步研究

The bioacitve detection and mechanism of cell-based absorptionon simulating gastrointestinal hydrolysis of casein

目的:研究牛乳酪蛋白在胃肠模拟水解条件下水解物的生物活性,以及这些肽类在细胞水平的吸收机制,为蛋白质生理作用机制研究奠定基础。方法:以牛乳酪蛋白为原料,对其进行体外模拟胃肠消化实验,通过检测消化液的DPPH自由基清除率和抑菌圈大小,分析其抗氧化和抗菌活性;建立Caco-2单层细胞模型对水解液进行过膜吸收,RP-HPLC分析过膜前后消化液组成,研究吸收情况。结果:模拟胃和肠消化时间均在2 h时,牛乳酪蛋白消化液的DPPH自由基清除率达到最大,分别为46.40%和56.7%,并且此时对大肠杆菌和金黄色葡萄球菌抑菌性能最强;细胞吸收实验表明2 h胃模拟水解液肽氮生物利用度达到7.79%,2 h肠模拟水解液达到15.11%,之后基本持平;亲水性的多肽能被成功吸收进入单细胞层下侧,但疏水性多肽大部分不易通过,易被降解或阻止。结论:牛乳酪蛋白在模拟消化条件下能产生生物活性肽类,并能被肠细胞吸收。

Objective： To study on bioative detetion and cell-based absorption mechanisms of gastrointestinal hydrolysis derived from bovine casein. It can further elucidate physiological mechanisms of food protein to humanbeing.Methods： Bovine milk casein was hydrolyzed in vitro simulating gastrointestinal digestion.The hydrolysate＇s antioxidant and antimicrobial activity were detected through the DPPH free radical clearance rate analysis and the bacteriostatic ring size determination. In addation,Caco-2 monolayer cell model was optimizated and established to simulate the membrane absorption of hydrolysate. RP-HPLC was used to analyze the digestive juices before and after across the membrane.Results： It showed the DPPH free radical clearance rates reached maximum,46.40% of 2 h-Gastricand 56.7% of 2h-Gastroin-testinal digestions from bovine casein.At the same time,the inhibition activity on Escherichia coli and Staphylococcus aureus also achieve maximum. Experiment results showed that hydrolyzed 2 h stomach simulation peptide absorption nitrogen bioavailability of 7.79%,2 h hydrolyzed imtestines simulation of 15.11%,after the flat.The peptide can be successfully absorb water into single cell layer under the side,but most hydrophobic peptide by not easily,easy degradation or stop.Conclusion： The gastrointestinal hydrolysate of casein can produce bioactive peptides as well as absorb by intestinal cell monolayer.