不同添加剂对酪蛋白可食膜理化性质的影响

Effects of Different Additives on the Physicochemical Properties of Casein Edible Film

酶可催化蛋白质分子内交联,多糖和多酚可与蛋白质发生分子间相互作用,3种添加剂均可改善蛋白质的功能性质。为提高酪蛋白(CA)可食膜的应用范围,研究了谷氨酰胺转氨酶(TG酶)、表没食子儿茶素没食子酸酯(EGCG)和壳聚糖(CS)对酪蛋白可食膜结构及性能的影响。测定膜溶液的粒径和电位,对复合膜机械性能、色泽和水蒸气透过率等指标进行表征。结果表明,TG酶、EGCG和CS对膜结构均影响显著,6组样品中添加EGCG和CS的样品(CAEC组)性能最佳。添加TG酶后,膜的机械性能有所提高,而水阻隔能力下降。添加EGCG后膜颜色变暗,抗拉伸强度提高,而韧性下降。添加CS后膜的抗拉伸强度提升,韧性也下降。同时添加EGCG和CS后,所得薄膜拥有良好的抗拉伸强度、水阻隔能力和较强的自由基清除能力。通过向酪蛋白膜中引入TG酶、EGCG和CS,赋予CA可食膜良好的机械性能和自由基清除能力,提高其水阻隔能力。研究结果对开发新型蛋白基可食膜具有一定意义。

Enzymes can catalyze the oxidative cross-linking of proteins, and there is molecular interaction between polysaccharides or polyphenols with proteins. In order to enhance the application range of casein(CA) edible film, the effects of transglutaminase(TG enzyme), epigallocatechin gallate(EGCG) and chitosan(CS) on film structure and properties were studied. The particle size and zeta-potential of the film solution were measured, and the mechanical properties, color and water vapor permeability of the composite film were characterized. The results showed that TG enzyme,EGCG and CS all had significant effects on the film structure, and the CAEC group with EGCG and CS added had the best performance among the groups of samples. After adding TG enzyme, the mechanical property of the film was improved, but the water barrier property decreased. After the addition of EGCG, the color of the film darkened, and the tensile strength was improved, but the toughness of film was greatly reduced. After the addition of CS, the tensile strength of the film increased, and its toughness also decreased. After adding both EGCG and CS, the film not only had good tensile strength but also exhibited certain water vapor barrier ability. It exhibited stronger free radical scavenging ability compared with other composite films, and its toughness decreased compared with the original casein film. This study introduced TG enzyme, EGCG and CS to the CA film, which gave it good mechanical properties, free radical scavenging ability and water barrier ability. Overall, this study has some guiding significance for the development of new protein-based edible film.