制麦白地霉的筛选及其初步应用

Selection of Geotrichum and Its Preliminary Application

对40株白地霉产β-葡聚糖酶、木聚糖酶、中性蛋白酶和纤维素酶的酶活情况进行研究,以加权评分对这些酶活进行分析评价,从中选出4株白地霉菌株(3号、12号、18号和39号)作为制麦用微生物。通过大麦制麦试验证明:这4株白地霉均对麦芽的溶解具有促进作用,其中12号白地霉的效果最好。与空白对照相比,制得的白地霉麦芽中,β-葡聚糖质量分数降低了17.8%,60min的滤液体积提高了35.4%,糖化力增加了10.3%,α-氨基氮质量分数增加了7.3%,其他理化指标也均符合QB1686-2008。将12号白地霉麦芽与对照麦芽分别进行了啤酒酿造实验,结果表明:白地霉麦芽的酿造性能优于空白对照麦芽,两种麦芽所酿啤酒的理化指标均符合GB 4927-2008。

The activities of β-glucanase,xylanase,protease and cellulase produced by 40 strains of Geotrichum candidum were studied in this manuscript.The weighted mark method was used to analyze activities of the above enzymes,and four G.candidum strains including No.3,No.12,No.18 and No.39 were selected as the malting microbial strains.The malting trials indicated that four G.candidum strains could improve the modification of malt and No.12 was the best one.Compared with that of the control,β-glucan content in final malt produced by G.candidum No.12 was decreased by 17.8%,and filtration volume in sixty minutes,diastatic power and free amino nitrogen content increased by 35.4%,10.3% and 7.3%,respectively.Meanwhile,other characteristics of the final malt met the requirement of QB1686-2008.The results of fermentation experiment shown that the brewing characteristics of microbial malt was better than that of the control malt,and the beer brewed with microbial malts or control malts both met the requirement of GB4927-2008.