加酶挤压高粱小曲酒生产工艺的响应面优化

Design and Optimization of an Efficient Enzymatic Extrusion Pretreatment for Xiaoqu Liquor Fermentation

采用加酶挤压法解决膨化高粱粘度高,糖化难的问题,研究了加酶挤压、不加酶挤压和蒸煮3种处理方式得到的高粱淀粉的物性差异,并将得到的3种高粱样品分别进行固态、液态和半固态发酵。结果表明,加酶挤压对高粱淀粉结构破坏最彻底,加酶挤压、不加酶挤压和蒸煮处理高粱淀粉均在22°出现新的B型衍射峰,相对结晶度分别为6.96%、10.89%和9.53%,糊化度分别为99.36%、51.27%和46.06%,加酶挤压高粱的峰值粘度降低至163mPa·s。加酶挤压高粱固态、液态和半固态发酵的产酒率分别为50.65%、47.83%和92.23%,半固态发酵产酒率较其它两种发酵方式提高了近一倍。通过响应面分析,预测出加酶挤压最佳工艺参数为高粱水分质量分数33.28%,套筒温度98.40℃,加酶量1.62‰,优化后的产酒率为93.73%。

To solve the problem of high viscosity and difficult saccharification of extrued sorghum starch,an enzymatic extrusion liquefaction pretreatment was used. Differences between sorghum starches treated by enzymatic extrusion,conventional extrusion and cooking were studied and the ethanol yield of different fermentation methods was compared. Results showed the morphology of sorghum starch treated by enzymatic extrusion was most damaged. XRD data indicated the sorghum starches generated strong peaks of B-type crystallites at 22°,the crystallinity of sorghum starches treated by enzymatic extrusion,conventional extrusion and cooking were 6.96%,10.89% and 9.53%. Sorghum starches tended to be more appropriate for fermentation because its extent of gelatinization was 99.36% and its peak viscosity was 163 cp. Semi-solid fermentation exhibited the highest fermentation efficiency of 92.23% among the different three fermentation methods. Based on Response surface methodology(RSM),the optimum extrusion conditions to obtain maximum fermentation efficiency of 93.73% were at the BT of 98.40 ℃,MC of 33.28%,and AC of 1.62‰.