蛋白质热处理对绿豆蛋白-高酰基结冷胶乳液凝胶性质的影响

Effect of Protein Heat Treatment on Properties of Mung Bean Protein-High Acyl-Gellan Emulsion Gel

本实验将绿豆蛋白在40、55、70、85、100℃的条件下热处理15、30、45、60、120 min,制备绿豆蛋白-高酰基结冷胶乳液凝胶,分析了凝胶的硬度、持水性、色度、溶解度、蛋白质二级结构及凝胶微观结构,以探究绿豆蛋白热变性对其形成乳液凝胶的性质影响。研究表明:随着热处理温度提高,热处理时间延长,凝胶硬度、持水性先增大后减小,在85℃、30 min达到最大值,分别为1403.91±12.05 N、99.715%±0.022%。热处理显著降低了凝胶亮度L*(P<0.05),提高了红度值a*。凝胶溶解度结果表明,形成此凝胶的主要分子间作用力为疏水键及氢键。当热处理温度升高,热处理时间延长,形成凝胶的键先增多后减少,在85℃、30 min时达到最大值,其疏水键及氢键浓度分别为10.87±0.02 mg/g、4.03±0.02 mg/g。凝胶二级结构相对含量结果显示:热处理会导致凝胶二级结构发生显著变化(P<0.05)。凝胶微观结构证明:持水性及硬度高的凝胶具有更致密的网络结构。综合来看,85℃、30 min的热处理条件改善凝胶特性的效果最好。本研究为提高绿豆蛋白-高酰基结冷胶乳液凝胶的性能改善和进一步开发利用提供理论依据。

In this study, mung bean protein was heat-treated at 40, 55, 70, 85 and 100 ℃ for 15, 30, 45, 60 and 120 min,respectively. Mung bean protein-high acyl gellan gum emulsion gel was prepared and its hardness, water holding capacity,color, solubility, protein secondary structure and gel microstructure were studied analyzed to explore the influence of mung bean protein thermal denaturation on the properties of emulsion gel. Studies showed that with the increasing of heat treatment temperature and the extension of heat treatment time, the gel hardness and water holding capacity firstly increased and then decreased, and reached the maximum values at 85 ℃ and 30 min, which were 1403.91±12.05 N and 99.715%±0.022%, respectively. Heat treatment significantly reduced the gel brightness L*(P<0.05) and increased the redness value a*. The gel solubility results showed that hydrophobic bond and hydrogen bond were the important intermolecular forces to form the gel. With the increasing of heat treatment temperature and the extension of heat treatment time, the bonds forming the gel firstly increased and then decreased, and reached the maximum at 85 ℃ and 30 min. The hydrophobic bond and hydrogen bond concentrations were 10.87±0.02 mg/g and 4.03±0.02 mg/g, respectively. The relative content of gel secondary structure showed that the secondary structure of gel was significantly changed after heat treatment(P<0.05). The picture of the microstructure of the gel proved that the gel with high water holding capacity and hardness had a denser network structure. In summary, the heat treatment conditions of 85 ℃ and 30 min had the best effect on improving the gel properties. This research could be the theoretical basis for improving the performance of mung bean protein-high acyl gellan gum emulsion gel and further development.