酸面团发酵过程中面团流变及面筋蛋白降解变化研究

实验选用酿酒酵母、德氏乳杆菌保加利亚亚种和短乳杆菌进行不同菌种的酸面团发酵,研究发酵过程中面团流变及面筋蛋白降解变化,为酸面团制品及其品质与生产提供理论参考。分析了酿酒酵母(Sce)发酵、酿酒酵母和德氏乳杆菌保加利亚亚种混合(Sce-Lb)发酵以及酿酒酵母和短乳杆菌(Sce-Lbr)混合发酵过程中面团流变及面筋蛋白降解变化。研究结果表明:3种发酵方式下面团pH值都随着发酵时间增加而降低,且Sce-Lbr发酵时酸化速度最快;发酵过程中面团的弹性模量和黏性模量都随着发酵时间的增加而降低,发酵过程中弹性模量始终大于黏性模量即面团的损耗因子始终小于1,其中Sce-Lbr发酵过程中黏弹性降低程度最大;发酵过程中面团的湿面筋含量和面筋指数都降低,且降低程度为Sce-Lbr>Sce-Lb>Sce,与酸化程度一致,其中Sce-Lbr发酵至12 h时由于过度酸化导致面筋蛋白结构的完全破坏已经无法洗出湿面筋;发酵过程中面团中的游离巯基含量随着发酵时间的增加而显著增加,其中Sce发酵12 h后游离巯基含量趋于稳定,而Sce-Lb和Sce-Lbr长时发酵后其游离巯基含量持续显著增加。

Research on the Change of Dough Rheology and Gluten Protein Degradation during Sourdough Fermentation

In this experiment,Saccharomyces cerevisiae,Lactobacillus delbrueckii subsp.bulgaricus and Lactobacillus brevis were selected to conduct the sourdough fermentation of different strains,and the changes of dough rheology as well as gluten protein degradation during the fermentation process were studied,so as to provide theoretical reference for sourdough products as well as their quality and production.The changes of dough rheology and gluten protein degradation during the process of fermentation of Sce,Sce-Lb and Sce-Lbr were analyzed.The results showed that the pH value of the dough samples were decreased with the increase of fermentation time under three fermentation methods,and the acidification speed of Sce-Lbr fermentation was the fastest.In the process of fermentation,the elastic modulus (G’) and the viscosity modulus (G") of the dough samples decreased significantly with the increase of the fermentation time and G’ were always greater than G" during the fermentation process.The viscoelasticity decreased the most during Sce-Lbr fermentation.The wet gluten content and gluten index of dough decreased significantly during fermentation,and the degree of the reduction was Sce-Lbr>Sce-Lb>Sce-Lbr,which was consistent with acidification degree.The wet gluten could not be washed out when Sce-Lbr fermented for 12 h because of the complete destruction of gluten structure caused by excessive acidification.The content of free sulfhydryl groups increased significantly with the increase of fermentation time,and it tended to be stable after 12 hours of Sce fermentation,while the content of free sulfhydryl groups in Sce-Lb and Sce-Lbr continued to increase significantly after long-term fermentation.