不同种类大豆蛋白对冷冻发酵面团馒头 品质的影响机制Effect mechanism of different kinds of soy protein on the quality of frozen fermented dough buns

旨在为大豆蛋白在冷冻发酵面团中的应用提供一定的理论依据，对添加大豆分离蛋白（SPI）、质构化大豆分离蛋白（TSP）、水解大豆分离蛋白(SPH)的冷冻发酵面团馒头及冷冻发酵面团进行研究，分析了添加不同种类大豆蛋白的冷冻发酵面团馒头的理化指标（比容、水分含量、pH），并通过测定冷冻发酵面团的二硫键含量、蛋白质二级结构和微观结构，探讨不同种类大豆蛋白对冷冻发酵馒头品质的影响机制。结果表明：添加SPH的发酵面团冷冻储藏前后所蒸制的馒头比容变化最小，在冷冻储藏40 d时蒸制的馒头比容相比冷冻储藏10 d增加了4.59%；同一冷冻储藏时间下添加SPH的发酵面团蒸制的馒头水分含量最低；添加大豆蛋白可以减小在冷冻储藏过程中发酵面团馒头pH的下降速率，至少可延长冷冻发酵面团10 d的保质期；通过傅里叶红外光谱和激光共聚焦对冷冻发酵面团蛋白质结构分析，得出添加3种大豆蛋白均会降低面筋蛋白网络结构的均匀性和连续性，SPI和TSP对面筋蛋白网络结构的影响小于SPH，但在冷冻储藏过程中添加SPH的发酵面团的面筋蛋白网络结构相对较为稳定。综上，大豆蛋白与面筋蛋白通过二硫键和非共价键相互作用，改变面筋蛋白网络结构的均匀性和连续性，从而引起馒头品质变化。In order to provide some theoretical basis for the application of soy protein in frozen fermented dough, the frozen fermented dough buns and frozen fermented doughs with soy protein isolates(SPI), texturised soy protein isolates(TSP), hydrolysed soy protein isolates (SPH)added were studied, the physicochemical indexes (specific volume, water content, pH) of frozen fermented dough buns added with different kinds of soy proteins were analysed, and the effect mechanism of different kinds of soy proteins on the quality of frozen fermented dough buns was investigated by determining the disulphide bond content, the secondary structure and microstructure of proteins in the frozen fermented doughs. The results showed that the specific volume of steamed buns before and after frozen storage of fermented dough with SPH had the smallest change, and the specific volume of steamed buns after 40 d of frozen storage increased by 4.59% compared with 10 d of frozen storage. The water content of steamed buns with SPH was the lowest under the same frozen storage time. The addition of soy protein could reduce the rate of pH drop of fermented dough buns during frozen storage, and could extend the shelf life of frozen fermented doughs by at least 10 d.The protein structure analysis of frozen fermented dough by Fourier infrared and laser confocal results showed that the addition of three soy proteins reduced the uniformity and continuity of gluten protein network structure.The effects of SPI and TSP on the gluten protein network structure were less than those of SPH, but the gluten protein network structure of fermented dough with SPH added during frozen storage was relatively stable.In summary, soy protein and gluten protein interact through S—S and non-covalent bonds to change the uniformity and continuity of the gluten protein network structure, causing changes in the quality of steamed buns.