γ-聚谷氨酸提高冷冻甜面团面包质构和感官特性研究
Study on the enhancement of texture and sensory attributes of frozen sweet dough bread using γ-poly glutamic acid
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摘要: 研究了一种通过生物发酵制得的多聚氨基酸——γ-聚谷氨酸（γ-PGA）对冷冻甜面团抗冻活性和冷冻甜面团面包质量的影响。主要采用差示扫描量热仪（DSC）、质构仪和感官评定等方法研究了γ-PGA的抗冻活性、γ-PGA添加量和冻藏条件（恒温冻藏和冻融循环）对冷冻甜面团中可冻结水含量、面包比容、质构和感官品质的影响。结果表明,γ-PGA的抗冻活性值为8.027g不可冻结水/g,说明其具有非常好的抗冻活性;恒温冻藏和冻融循环后,冷冻甜面团中可冻结水含量明显增多,面包比容显著减小,质构变差,感官品质下降,尤其是冻融循环后,这种变化趋势更为明显;在相同冻藏条件下,添加0.5%和1%γ-PGA后,冷冻甜面团中可冻结水含量显著减少、冷冻甜面团面包比容显著增大、面包质构明显改善、面包感官评分明显提高,其中以1%γ-PGA的作用效果最好。Abstract: The effects of γ-poly glutamic acid (γ-PGA) produced by biological fermentation on the freezing resistance of frozen sweet dough and its bread-making properties are studied. Differential Scanning Calorimeter (DSC) , Texture Analyzer and sensory evaluation, and so on were used to investigate the antifreeze activity ofγ-PGA, and frozen water content, bread specific volume, texture and sensory attributes of frozen sweet dough with different amount of γ-PGA at different frozen storage conditions (frozen storage at constant and fluctuating temperature) . Results showed that:the antifreeze activity of γ-PGA was 8.027 g unfrozen water/g, indicating that γ-PGA had good antifreeze activity. The addition of γ-PGA into frozen sweet dough caused a significant decrease in ice melting enthalpy of frozen sweet dough (ΔHdough) , indicating that the freezable water content decreased significantly. The addition of 0.5% and 1% γ-PGA significantly improved the bread specific volume, texture and sensory scores of frozen sweet dough, and the bread made of frozen sweet dough with 1%γ-PGA was the best.
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