Abstract
In total, 16 yeast were isolated from Chinese strong flavour Daqu samples and underwent RAPD analysis and identification. Totally, 11 different species were identified among these isolates including Saccharomyces cerevisiae, Hanseniaspora vineae, Pichia kluyveri, Trichosporon asahii, Wickerhamomyces anomalus, Kluyveromyces lactis, Yarrowia lipolytica, Wickerhamomyces mori, Galactomyces geotrichum, Dabaryomyces hansenii, and Saccharomyces kudriavzevii. To understand the impact of these yeast strains on the quality and flavour of Daqu, we then assessed volatile compounds associated with Daqu samples fermented with corresponding strains. These analyses revealed strain YE006 exhibited the most robust ability to produce ethanol via fermentation but yielded relatively low quantities of volatile compounds, whereas strain YE010 exhibited relatively poor fermentation efficiency but produced the greatest quantity of volatile compounds. These two yeast strains were then utilized in a mixed culture to produce fortified Daqu, with the optimal inoculum size being assessed experimentally. These analyses revealed that maximal fermentation, saccharifying, liquefying, and esterifying power as well as high levels of volatile compounds were achieved when using a 2% inoculum composed of YE006/YE010 at a 1:2 (v/v) ratio. When the liquor prepared using this optimized fortified Daqu was compared to unfortified control Daqu, the former was found to exhibit significantly higher levels of flavour compounds and better sensory scores. Overall, our findings may provide a reliable approach to ensuring Daqu quality and improving the consistency and flavour of Chinese strong-flavour liquor through bioaugmentation.
Highlights
Chinese strong-flavour liquor is a traditional distilled alcoholic beverage that plays a central role in many aspects of Chinese culture
Preliminary screening of yeast strains In total, 16 yeast colonies exhibiting different morphological characteristics were isolated from samples of Chinese strong-flavour Daqu and were evaluated via a Random amplified polymorphic DNA (RAPD)-PCR approach which grouped these isolates into 11 clusters at a 68% similarity level (Fig. 2)
Four of these yeast isolates (YE006, YE009, YE015, and YE016) were found in cluster V, while strains YE002 and YE004 were incorporated into group VI and strains YE007 and YE010 were incorporated into cluster IX
Summary
Chinese strong-flavour liquor is a traditional distilled alcoholic beverage that plays a central role in many aspects of Chinese culture. As traditional Daqu production involves the utilization of non-autoclaved raw materials in an open environment, the microbial communities that facilitate the eventual solid-state fermentation process are sensitive to changes in moisture, temperature, pH, and acidity such that this process cannot be reliably controlled. This has the potential to yield Daqu of inconsistent quality, resulting in higher production costs and reduced fermentation power that can compromise the liquor production process
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
