罗非鱼蛋白-乳清蛋白复合乳液负载β-胡萝卜素的研究

Load of β-Carotene in Tilapia Protein-Whey Protein Composite Emulsion

为了提高β-胡萝卜素的稳定性和生物利用率,充分利用双蛋白的营养和功能特性优势,以罗非鱼分离蛋白(tilapia protein isolate,TPI)和乳清分离蛋白(whey protein isolate,WPI)混合液作为乳化剂,通过高压均质结合热处理制备负载β-胡萝卜素的TPI-WPI复合乳液,探讨两种蛋白的质量比(2∶1、1∶1、1∶2)对乳液稳定性、抗氧化活性及体外消化特性的影响。结果表明,与单一的TPI和WPI乳液比较,TPI-WPI复合蛋白乳液的稳定性及β-胡萝卜素的生物利用率提高。当TPI与WPI质量比为1∶2时,复合蛋白乳液初始粒径为259.18 nm,zeta电位绝对值为28.23 m V,乳液的稳定性好,4℃贮藏21 d不分层;当TPI与WPI质量比为2∶1时,复合蛋白乳液贮藏21 d后β-胡萝卜素保留率达到62.36%,DPPH自由基和ABTS+自由基清除率分别为54.83%和40.11%,经体外消化后,β-胡萝卜素的生物利用率达24.76%,乳液游离脂肪酸释放率高。因此,WPI的添加可以提高复合蛋白乳液的稳定性,而TPI的添加可以提高乳液负载β-胡萝卜素的稳定性和生物利用率。研究结果可为混合蛋白构建稳定的乳液体系及活性成分的递送提供参考。

To improve the stability and bioavailability of β-carotene and make full use of the nutritional and functional advantages of double proteins,this study mixed tilapia protein isolate(TPI)and whey protein isolate(WPI)as the emulsifier,and prepared the composite protein emulsion loaded with β-carotene through high pressure homogenization and heat treatment,thus exploring the effects of the mass ratio(2∶1,1∶1,and 1∶2)of the two kinds of proteins on the stability,antioxidant activity,and in vitro digestion characteristics of the emulsion.The results showed that,the stability of the TPI-WPI composite emulsion and the bioavailability of the loadedβ-carotene were significantly improved as compared with single TPI or WPI emulsion. When the mass ratio of TPI and WPI was 1∶2,the initial particle size of TPI-WPI composite emulsion was 259.18 nm,and the absolute value of zeta potential was 28.23 mV. In addition,the composite emulsion had good stability,and there was no delamination after storage for 21 d at 4 ℃. When the mass ratio of TPI and WPI was 2∶1,the retention rate of β-carotene in composite emulsion was 62.36% after storage for 21 d,and DPPH free radical and ABTS+free radical scavenging rates were 54.83% and 40.11%. After in vitro digestion,the bioavailability of β-carotene was 24.76% with the high release rate of free fatty acids in the emulsion. Therefore,the addition of WPI enhanced the stability of the composite emulsion,and the addition of TPI increased the stability and bioavailability of β-carotene in the emulsion. The findings of this study provided a basis for the construction of stable emulsion system and the delivery of active ingredients for mixed proteins.