中高温大曲表面霉菌分离鉴定与控制研究

Isolation, identification and control of molds on the surface of medium-high-temperature Daqu

为针对性控制曲坯表面霉菌的生长,该研究在原有制曲工艺的基础上,对大曲生产过程中关键控制点进行合理调整,从曲坯表面分离出霉菌菌株并进行鉴定,同时通过研究安曲间距、覆盖物、一次翻曲时间以及霉菌擦拭等对曲坯表面霉菌生长情况以及曲坯感官和理化指标等的影响,摸索出控制冬春季中高温大曲表面霉菌生长的措施。结果表明,从曲坯表面分离纯化得到一株霉菌菌株L1,经鉴定为少根根霉(Rhizopus arrhizus)。在原有制曲工艺的基础上,保持安曲间距为2.0~2.5 cm、选择厚度为12~15 cm稻草作为覆盖物、调整一次翻曲时间为安曲后第3天,在此控制条件下,曲坯表面霉菌生长面积可降至50%,长度控制约为2 mm。一次翻曲时进行霉菌擦拭操作结果表明,断面菌丝更为明显和饱满,糖化力和酯化力指标略有提高,分别为783.3 mg/(g·h)、643 mg/(25 g·7 d),该研究对中高温大曲质量稳定和提升具有一定的参考意义。

In order to control the growth of molds on the surface of Daqu,on the basis of the original Daqu-making process,the key control points in the production of Daqu were reasonably adjusted,and mold strains were isolated from the surface of the Daqu and then identified.At the same time,the effects of the spacing between Anqu,mulch,first Fanqu time,and molds wiping on the growth,of mold on the surface of Daqu,and on the sensory,physicochemical indexes of Daqu were studied,and the measures to control the growth of molds on the surface of medium-high temperature Daqu in winter and spring were explored.The results showed that a fungus strain L1 was isolated and purified from the surface of Daqu,and it was identified as Rhizopus arrhizus.On the basis of the original Daqu-making process,the spacing between the Daqu was maintained at 2.0-2.5 cm,the straw with a thickness of 12-15 cm was selected as the mulch,and the first Fanqu time was 3 d after Anqu.Under these control conditions,the mold growth area on the surface of the Daqu could be reduced to 50%,the length was controlled to about 2 mm.The mold wiping was operated during the first time Fanqu.Results showed that the cross-sectional hyphae were more pronounced and full,the indexes of saccharification power and esterification power were slightly increased,which were 783.3 mg/(g·h)and 643 mg/(25 g·7 d),respectively.The research had certain reference significance for the stability and improvement of the quality of medium-high-temperature Daqu.