清香型大曲中高糖化力霉菌的筛选、鉴定及其挥发性风味物质分析

Screening,identification of mold with high saccharifying power from light-flavor Daqu and its volatile flavor compounds

采用传统微生物培养分离法、水解圈法及糖化力测定从牛栏山清香型大曲中分离筛选高糖化力的霉菌,通过形态观察及分子生物学技术对其进行菌种鉴定,并采用顶空固相微萃取结合气质联用法(HS-SPME-GC-MS)测定其代谢产物中的挥发性风味成分。结果表明,共筛选到5株高糖化力霉菌,经鉴定,菌株Q2、Q11为米曲霉(Aspergillus oryzae)、菌株Q19、Q70为黑曲霉(Aspergillus niger)、菌株Q48为米根霉(Rhizopus oryzae),其中菌株Q19的糖化力最高(2 288.17 U/g)。从5株霉菌的代谢产物中共检出44种挥发性物质,包括6种醇类、18种酯类、9种醛酮类、11种芳香类。不同菌株产生的风味物质差异较大,菌株Q19和Q48代谢物中挥发性风味物质较为丰富且含量较高,且菌株Q2和Q11代谢物中1-辛烯-3-醇含量较高,菌株Q19代谢物中苯乙醇含量较高,菌株Q48和Q70代谢物中十六酸乙酯和亚油酸乙酯等高沸点酯类化合物含量较高。

Molds with high saccharifying power were isolated and screened from Niulanshan light-flavor Daqu by traditional microbial culture and separation method,hydrolytic circle method and saccharification power test,identified by morphological observation and molecular biology techniques,and the volatile flavor components in the metabolites were determined by headspace solid phase microextraction combined with gas chromatography-mass spectrometry(HS-SPME-GC-MS).The results showed that 5 strains of molds with high saccharification power were screened,the strains Q2 and Q11 were identified as Aspergillus oryzae,the strains Q19 and Q70 were identified as Aspergillus niger,and the strain Q48 was identified as Rhizopus oryzae.Among them,the strain Q19 had the highest saccharifying power(2288.17 U/g).A total of 44 volatile substances were detected from the metabolites of 5 strains of molds,including 6 alcohols,18 esters,9 aldehydes and ketones,and 11 aromatics compounds.The flavor substances produced by different strains were quite different,the volatile flavor substances in the metabolites of strains Q19 and Q48 were relatively rich and high in content,the content of 1-octene-3-ol in the metabolites of strains Q2 and Q11 was high,the content of phenylethanol in the metabolites of strain Q19 was high,and the content of easters with high boiling point such as palmitic acid ethyl ester and ethyl linoleate in the metabolites of strains Q48 and Q70 was higher.