马铃薯乳清复合蛋白乳液凝胶的制备和特性

Gelling characteristics of mixed protein emulsion with varying ratios of potato protein to whey protein

摘要:

为开发马铃薯乳清双蛋白乳液凝胶， 以新鲜马铃薯为材料，采用碱溶酸沉法提取马铃薯蛋白（PP），然后与乳清蛋白（WP）制备马铃薯乳清复合蛋白乳液凝胶，通过FTIR、低场核磁（LF-NMR）、SEM、激光扫描共聚焦显微镜（CLSM）表征，结合流变、质构、色度、分子间力等测试，考察了m(PP)∶m(WP)对复合蛋白乳液凝胶特性的影响。结果表明，复合蛋白乳液凝胶综合特性要优于单一的马铃薯蛋白或乳清蛋白乳液凝胶。相比于m(PP)∶m(WP)＝10：0制备的马铃薯蛋白乳液凝胶，m(PP)∶m(WP)＝7：3、5：5制备的复合蛋白乳液凝胶的温度循环终点储能模量（G"）分别提高了114.7%和108.7%（P<0.05）；束缚水质量分数分别提高了2.01%和1.97%（P<0.05）；凝胶强度、弹性、胶黏性、恢复性和咀嚼性等质构特性显著增强（P<0.05）。CLSM和SEM显示m(PP)∶m(WP)＝7∶3、5∶5制备的复合蛋白乳液凝胶网络结构紧密，凝胶网络中油滴均匀分布在蛋白凝胶网络中，起到了更好支撑作用。β-折叠和β-转角结构是马铃薯乳清复合蛋白乳液凝胶中蛋白的主要二级结构，含量 约为70%。

Abstract:

Potato protein (PP), extracted from fresh potato by the alkali-soluble acid-precipitation method, was mixed with whey protein to fabricate the composite protein emulsion gel. The effect of PP to WP ratios (10:0, 7:3, 5:5、3:7, 0:10, w:w) on characteristics of mixing potato and whey protein emulsion gels were investigated by FTIR, low-field nuclear magnetic resonance (LF-NMR), scanning electron microscopy (SEM), Confocal laser scanning microscopy (CLSM), rheological and textural analysis, chrominance, and intermolecular force. The results showed that the comprehensive properties of composite protein emulsion gel were better than those of single potato protein or whey protein emulsion gel. The storage modulus(G") of the composite emulsion gels with the PP to WP ratio of 7:3 and 5:5 was 114.7% and 108.7% higher than that of the PP emulsion gels (PP: WP=10:0) (p<0.05). The gel strength, elasticity, adhesiveness, resilience, and chewability of composite emulsion gels with the PP to WP ratio of 7:3 and 5:5 were higher than those of PP emulsion gels (p<0.05). CLSM and SEM showed that the emulsion gels with the PP to WP ratio of 7:3 and 5:5 have dense networks and well-distributed emulsified oil droplets. The emulsion gels" primary secondary protein structure was β-helix and β-turn, which account for about 70%.