高活性天然酵母发酵剂的优化

Study on the optimization of sourdough starter with high activity

目的:研究标准化稳定天然酵母发酵剂的制备工艺,探究干燥工艺及保护剂对天然酵母活性的影响,并研究其贮藏活性。方法:选用多种水果制备天然酵母,研究其发酵过程并分离菌株通过ITs和16s基因测序在数据库中比对鉴定优势菌株。以干燥工艺处理后的存活率和贮藏活性为指标,通过选择干燥工艺、样品状态和保护剂配方来获得最佳方案。结果:葡萄天然酵母制备的面包具有最好的比容、孔隙度和硬度。在此基础上,以干燥存活率和贮藏活性为指标得到两种保护效果较好的配方:①冷冻干燥优势菌种菌液,脱脂乳粉35%、麦芽糊精7.5%和海藻糖25%,干燥存活率约为93%;②天然酵母整体喷雾干燥,脱脂乳粉35%、麦芽糊精10%和海藻糖15%,干燥存活率约为90%。结论:喷雾干燥的发酵剂贮藏活性下降较快,而冷冻干燥的发酵剂贮藏活性较强。

Objective:This research aimed to study the preparation of standardized and stable sourdough starter,to explore the effects of different drying processes and protective agents on the survival rate of sourdough,and examine its storage activity.Methods:A variety of fruits were selected to prepare sourdough,the fermentation process was studied,and the strains were isolated and identified by ITs and 16s gene sequencing in the database.The optimum scheme was obtained by selecting the drying process,sample state and protectant formulation with the activity after drying and storage activity as indexes.Results:It was found that the bread prepared with grape sourdough had the best specific volume,porosity and hardness.On this basis,the drying survival rate and storage activity were used as indexes to study the combination of drying protectants.Finally,two better protective agent formulations were obtained by orthogonal experiment:①Freeze-dried the dominant pure bacterial solution,skim milk 35%,maltodextrin 7.5%and trehalose 25%,and the drying survival rate was about 93%.②Spray dried sourdough germ whole,skim milk 35%,maltodextrin 10%and trehalose 15%,and the drying survival rate was about 90%.Conclusion:It was found that the storage activity of the spray-dried starter decreased rapidly,while that of the freeze-dried starter was slower.