酵子面包在贮藏过程中理化及微生物指标的变化

Changes in Physicochemical and Microbial Properties during Storage of Bread Made with Jiaozi, A Traditional Starter Culture for Steam Bun in Northern China

测定在25℃条件下贮藏期间酵子面包和酵母面包的理化指标及微生物指标的变化,得出面包老化的物性参数变化规律,揭示其抗老化机理。对感官指标、硬度、水分活度、热特性、自由水含量、电镜扫描、破碎率、膨润度、质构分析特性等理化指标及微生物指标进行测定。结果表明:随贮藏时间延长,面包水分含量显著下降,硬度明显上升。与酵母面包相比,酵子面包具有水分含量较高,硬度较小,淀粉颗粒更容易发生团聚等特性,物性学研究结果显示,将传统发酵剂酵子应用于面包生产,具有较好地延缓淀粉回生和老化的效果。确定面包老化的定量物性参数范围,为由定性分析向定量参数分析转变作了有益探索。

This study investigated the changes in physicochemical and microbial properties during storage at 25℃ of bread made with Jiaozi, a traditional starter culture for steamed bun in northern China, established the changing patterns of the physical parameters related to bread staling, and revealed the anti-staling mechanism, Sensory evaluation indexes, hardness, water activity, thermal characteristics, free water content, scanning electron micrograph, disruption ratio, swelling degree and texture profile analysis （TPA） properties were determined as well as microbial indexes. The results showed that the water content of bread declined, and hardness rose remarkably with extended storage time. Compared with sourdough bread, Jiaozi bread contained higher levels of water, its texture was softer, and its starch granules were more prone to agglomeration. The quantitative physical parameter range for bread staling was also established. TPA showed that starch retrogradation and staling were effectively inhibited by applying the traditional starter culture in bread. This study can provide a beneficial exploration for the transformation of the traditional qualitative analysis to quantitative analysis in bread production.