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摘要：本文针对乳清蛋白膜机械性能未能达到食品包装膜的程度，研究了重组细菌漆酶和阿魏酸的共同作用对乳清蛋白交联成膜及其性能的影响，并且从膜厚度、机械强度、透明度、颜色的变化、膜蛋白溶解度、体外消化率及气体透过率等方面测定膜性能的变化，结果表明在添加相同体积的酶液和不同浓度的阿魏酸溶液之后膜的性能变化是：在40 ℃、50 ℃、60 ℃的处理温度下，膜厚度随着阿魏酸添加量的增加而略微增大，膜的机械强度增强；随着阿魏酸添加量的增加，膜的透明性增大而膜越不透明，而膜的颜色逐渐加深，且膜的亮度和黄度显著增加；蛋白溶解度随着阿魏酸添加量的增加呈现出增加的趋势，同时在3 %的阿魏酸添加量下达到最大值，这说明乳清分离蛋白很稳定，不会发生物质的转移；随着阿魏酸的浓度增加，膜的体外消化率呈现上升的趋势，这说明通过漆酶和阿魏酸共同作用的改性蛋白膜更容易被人体吸收利用；随着阿魏酸浓度的增加，膜的氧气透过率减小，二氧化碳和水蒸气的透过率增加，这表明膜具有良好的隔绝氧气的作用和亲水性。总之，在漆酶和阿魏酸共同作用后得到的膜性能大大改善，有望成为新型无毒安全健康的食品包装材料。25979
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毕业论文关键词：乳清蛋白；重组细菌漆酶；可食用膜；阿魏酸
Effects of Recombinant Bacterial Laccase on The Properties of Whey Protein Films
Abstract： In this paper, due to the mechanical properties of whey protein films failing to meet the extent of food packaging film, the effect of recombinant bacteria laccase and ferulic acid on the cross-linking of whey protein and its properties were studied. And the change in films properties was measured from the aspects of film thickness, mechanical strength, transparency, color change, film protein solubility, in vitro digestibility and gas permeability.The results show that the performance of the film after adding the same volume of enzyme solution and different concentrations of ferulic acid solution is as follows. At a treatment temperature of 40 °C, 50 °C and 60 °C, the film thickness increases slightly with the addition of ferulic acid, and the mechanical strength of the film is enhanced; With the increase of ferulic acid, the transparency of the film increased and the film became opaque, and the color of the film gradually deepened, and the brightness and yellowness of the film increased significantly; The solubility of protein increased with the increase of ferulic acid, and reached the maximum at 3% ferulic acid, which indicated that the whey protein was stable and did not transfer; With the increase of the concentration of ferulic acid, the in vitro digestibility of the film showed an increasing trend, which indicated that the modified protein film, which was formed by laccase and ferulic acid, was more easily absorbed by the human body; As the concentration of ferulic acid increases, the oxygen permeability of the film decreases and the transmittance of carbon dioxide and water vapor increases, indicating that the film has a good barrier to oxygen and hydrophilicity. In short, the film performance greatly improved under the joint action of laccase and ferulic acid, which is expected to become a new non-toxic safe and healthy food packaging materials.
Key words: Whey protein ; Recombinant bacterial Laccases ; Edible films; Ferulic acid
目 录
摘要3
关键词3
Abstract3
Key words3
引言4
1 实验器材与方法4
1.1 实验材料 4
1.1.1 实验仪器与设备4
1.1.2试剂的配制4
1.2 实验方法及步骤5
1.2.1 漆酶的制备5
1.2.2 漆酶催化阿魏酸氧化交联乳清蛋白成膜5
1. 2. 3 考马斯亮蓝法测定蛋白浓度 6
1. 2. 4 膜厚度的测定 6
1. 2. 5 膜抗拉强度及断裂伸长率的测定 6