超高压处理对米糠蛋白功能及结构特性的影响研究

发布时间：2018-06-19 23:15

本文选题：超高压 + 米糠蛋白　；参考：《浙江大学》2017年硕士论文

【摘要】：蛋白质是人体健康必需的营养物质。近年来,随着人们对健康的追求,植物蛋白代替动物蛋白已经成为未来的发展趋势。在我国,米糠是一种产量巨大的加工副产物,而且它是优质蛋白米糠蛋白的重要来源。本文以米糠为原料,采用碱提法制备米糠蛋白,并对其进行超高压改性处理,探究超高压处理对米糠蛋白功能特性、结构特性的影响。其次,研究超高压对米糠清蛋白糖基化反应特性的影响,探究超高压处理对糖基化反应进程以及对糖基化反应产物功能特性的影响,主要结论如下:1、超高压处理能有效改善米糠蛋白的功能特性。采用100-500 MPa,保压时间为10min对米糠蛋白进行高压处理发现,与未经处理的米糠蛋白相比,经过100 MPa和200 MPa处理后米糠蛋白的溶解性得到显著改善,而随着压力的继续增加,米糠蛋白的溶解度下降。米糠蛋白的持水性和起泡性都随着压力的增大而增大,并且在500MPa时达到了最大值。高压后的米糠蛋白的持油性得到了提高,并在200 MPa下达到了最大值,而乳化稳定性在400 MPa下达到了最大值。与未经处理的米糠蛋白相比,经过超高压处理的米糠蛋白的乳化性、起泡稳定性和最小凝胶浓度显著改善,但是不同的处理压力之间没有显著性差异。2、为了探究超高压对米糠蛋白改性的机理,本文通过采用红外光谱、圆二色谱、表面疏水性、内源荧光光谱等方法探究超高压对米糠蛋白结构特性的影响。由红外光谱的结果发现,随着压力的增大,-OH伸缩振动特征峰持续发生红移,并在400MPa时达到了最大的偏移位移。-CH、C=O、C-N等伸缩振动的特征峰也都相应发生了一定的偏移。圆二色谱的结果表明,经过高压处理后,蛋白质中的a螺旋结构增多。相对内源荧光强度呈现先增大后减小的变化趋势,表明蛋白质的三级结构发生变化。同时,米糠蛋白的表面疏水性随着压力的增大而持续增大。通过分析表面疏水性与米糠蛋白功能特性之间的相关性发现,蛋白质的表面疏水性与其他功能特性之间具有很强的相关性。3、超高压处理对米糠清蛋白葡萄糖糖基化反应有一定的抑制作用。通过对超高压处理后的米糠清蛋白的糖基化反应初级阶段(A294)和高级阶段(A420)的反应进程进行测定,发现:与未经高压处理的蛋白相比,经过不同高压处理后的米糠清蛋白的初级和高级糖基化反应程度均降低。由此可得,高压后的米糠清蛋白与葡萄糖的糖基化反应初级阶段和高级阶段受到一定的抑制作用,且不同压力之间没有显著性差异。同时对反应过程中游离氨基含量以及接枝度进行计算,进一步验证了此结论。说明,超高压处理后对米糠清蛋白的结构变化是趋于不利于发生糖基化反应的方向进行的。4、超高压处理对米糠清蛋白糖基化反应产物的功能特性有一定的改善作用。对糖基化产物的功能性质进行研究发现,经过100 MPa处理可以提高米糠清蛋白的溶解度,但随着压力继续增大,溶解度呈现下降的趋势;在较低压力下,乳化性和乳化稳定性与未处理相比没有显著性的差异,当压力较大时,才有一定的增强效果;起泡性和持油性都随着超高压处理压力的增加而增加,并在400 MPa时达到了最大值,而持水性则在300 MPa达到了最大值。
[Abstract]:Protein is a necessary nutrient for human health. In recent years, with people's pursuit of health, plant protein has become a trend of future development. In China, rice bran is a very productive by-product, and it is an important source of high quality protein rice bran protein. In this paper, rice bran is used as raw material and the alkali extraction method is used in this paper. The rice bran protein was prepared and treated with ultra-high pressure, and the effect of ultrahigh pressure treatment on the functional properties and structural characteristics of rice bran protein was investigated. Secondly, the effect of ultra-high pressure on the glycosylation of rice bran albumin was studied, and the effect of ultra high pressure treatment on the process of glycosylation and the functional properties of glycosylation products were investigated. The following conclusions are as follows: 1, ultra high pressure treatment can effectively improve the functional properties of rice bran protein. Using 100-500 MPa and pressure holding time of 10min, the rice bran protein is treated with high pressure. Compared with untreated rice bran protein, the solubility of rice bran protein after 100 MPa and 200 MPa treatment has been significantly improved, and as the pressure continues to increase, The solubility of rice bran protein decreased. The water holding property and foaming ability of rice bran protein increased with the increase of pressure and reached the maximum at 500MPa. The oil holding property of rice bran protein after high pressure increased and reached the maximum value at 200 MPa, and the emulsification stability reached the maximum value under 400 MPa. In comparison with the emulsification of rice bran protein treated by ultra-high pressure, the foaming stability and minimum gel concentration significantly improved, but there was no significant difference between different treatment pressures.2. In order to explore the mechanism of super high pressure on rice bran protein modification, the paper adopted infrared spectrum, circular two chromatography, surface hydrophobicity and endogenous fluorescence spectrum. The effect of ultrahigh pressure on the structural characteristics of rice bran protein was explored. The results of infrared spectra showed that the peak of the -OH expansion vibration peak was red shift with the increase of pressure, and the maximum displacement.-CH, C=O, C-N and other characteristic peaks of the telescopic vibration at the time of 400MPa were also offset. The results of circular two chromatography The results showed that after high pressure treatment, the spiral structure of a increased in protein. The relative endogenous fluorescence intensity showed a tendency to increase first and then decrease, indicating that the three grade structure of protein was changed. Meanwhile, the surface hydrophobicity of rice bran protein increased with the increase of pressure. The surface hydrophobicity and rice bran protein function characteristics were analyzed. The correlation between the surface hydrophobicity of the protein and other functional properties has a strong correlation.3, and the ultra high pressure treatment has a certain inhibitory effect on the glucose glycosylation of rice bran albumin. Through the reaction to the primary stage (A294) and the advanced stage (A420) of the glycosylation of rice bran albumin after ultra high pressure treatment The process was determined. It was found that the primary and advanced glycosylation levels of rice bran albumin decreased after different high-pressure treatments compared with those without high pressure treatment. Thus, the primary and higher stages of glycosylation of rice bran albumin and glucose after high pressure were inhibited, and the pressure was different. There is no significant difference between them. At the same time, the content of free amino group and the degree of grafting in the reaction process are calculated, and the conclusion is further verified. It shows that the structure change of rice bran albumin after ultra high pressure treatment is.4 which tends to be disadvantageous to the direction of glycosylation, and the ultra high pressure treatment of rice bran albumin glycosylation product The functional properties of the glycosylated products showed that the solubility of rice bran albumin could be improved by 100 MPa treatment, but with the pressure continued to increase, the solubility showed a downward trend, and there was no significant difference in emulsifying and emulsifying stability compared with that of untreated under the lower pressure. When the pressure is large, it has a certain enhancement effect. The foaming and oil holding property increases with the increase of the pressure of ultra high pressure treatment, and reaches the maximum at 400 MPa, while the water holding capacity reaches the maximum at 300 MPa.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TS201.21

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