白酒大曲中产香微生物筛选及提升再造烟叶品质研究

Screening of an aroma-producing microorganism in Baijiu Daqu and its application on improving the quality of reconstituted tobacco extract

针对再造烟叶香气质较差的问题,从广西特香型白酒大曲中筛选能够利用再造烟叶萃取液中营养物质发酵产香的微生物,结合形态学及分子生物学方法对产香效果最佳的微生物进行菌株鉴定及发酵条件优化,利用GC-MS技术测定其产香的物质基础,并将其添加于再造烟叶中进行感官评价。结果表明:筛选出的Y-1菌株对再造烟叶萃取液中可溶性糖和蛋白质的利用能力最强,对萃取液的香气改善效果最佳;经鉴定,Y-1菌株为库德里阿兹威毕赤酵母(Pichia kudriavzevii),其在25℃、pH值为5、体积分数为80%的再造烟叶萃取液中发酵24 h后,能够显著提升萃取液中酯类、酮类、醇类和酸类等挥发性香气物质的含量,提升幅度分别达2.31倍、0.66倍、12.15倍和2.74倍,且萃取液中新增16种挥发性香气物质;Y-1菌株发酵萃取液添加于再造烟叶后,能显著增强其果香、甜香感及香气层次感,提升其吸味品质。

Microorganisms able to produce aroma from nutrients in reconstituted tobacco extract were screened from Guangxi′s unique aroma-type Baijiu Daqu in order to address the issue of low aroma quality of reconstituted tobacco extract.With morphological and molecular biology approaches,the best aroma-producing microbe was then identified,the cultivation and fermentation conditions were optimized and the material basis for scent improvement was investigated using GC-MS technology.The sensory analysis method was used to assess the aroma-enhancing effect.According to the findings,strain Y-1 improved the extract′s aroma the most and showed the greatest capacity to utilize soluble sugar and protein in the reconstituted tobacco extract.It was identified that Y-1 was Pichia kudriavzevii,and after fermentation under the cultivation of 25℃,pH=5,and 80%concentration in reconstituted tobacco extract for 24 hours,it could significantly improve the contents of volatile aroma substances in the extract,with esters,ketones,alcohols,and acids increasing by 2.31-fold,12.15-fold,0.66-fold and 2.74-fold,respectively.In addition,16 new volatile aroma components were detected after fermentation.When the fermented extract containing Y-1 was added to reconstituted tobacco leaves,it significantly enhanced the fruity,sweet aroma and aroma layering,improving the smoking quality.