Environmental and Physicochemical Characterization and Fungal Community of Two Batches of Chinese Luzhou-Flavored Daqu

Abstract

The environmental and physicochemical characteristics and fungal communities of two batches of Chinese Luzhou-flavored Daqu were investigated during the fermentation stage and storage period. The Daqu was processed on July 1, 2018 and August 1, 2018, and was identified as middle-temperature and middle and high-temperature Daqu, respectively. At the genus level, the dominant fungi were Aspergillus during the fermentation stage and Candida after three months of storage. Principal component analysis (PCA) and the unweighted pair group method with arithmetic mean (UPGMA) analysis revealed that the fungal community could be divided into two primary groups based on the fermentation and storage stages. Each large fungal population could then be divided into two smaller groups according to the batch. Notably, LEfSe [line discriminant analysis (LDA) effect size] analysis did not find any significantly different fungal populations between the two batches. Redundancy analysis showed that during the entire culture stage of two batches of Daqu, water content and fermenting power were positively correlated with Aspergillus and Wickerhamomyces, while water content correlated negatively with Rhizopus. During fermentation, environmental humidity correlated negatively with Wickerhamomyces in the two batches of Daqu. This study increases the theoretical understanding of Daqu preparation, especially function of the storage period and the fungal differences between batches of Daqu. Such information potentially enables the quality control of Daqu in order to improve quality by controlling the fungal community via the processing conditions and the addition of Candida.

Keywords:

• Environmental and physicochemical characterization
• fungus community
• Luzhou-flavoured Daqu
• redundancy analysis

Disclosure statement

The authors declare that they have no conflicts of interest.

Author contributions

Z. Huawei contributed equally to investigation, supervision, writing-review, and editing of this article. X.-J. Jiang supportively contributed to conceptualization of the article. Z.-Q. Wang contributed equally to the investigation and data curation. X. Zeng contributed equally to data curation and writing of the original draft. B.-Y. Xin contributed equally to data curation and writing of the original draft. Y. Wang, X. Zhang, and H.-L. Yang contributed equally to methodology. J. Qiao and R. Dong contributed equally to investigation and data curation. M.-Q. Huang and J. Zhang contributed equally to project administration and supervision.

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Additional information

Funding

This work was financially supported by the Science and Technology Project of Guannan (study on improving the quality of Tanggou liquor by microbial community analysis in the brewing process) (GN201903), Anhui University Students’ Innovation and Entrepreneurship Training Project (Grant No. 202010373090), and the Open Project Program of Beijing Key Laboratory of Flavor Chemistry, Beijing Technology and Business University (Grant No. SPFW2019YB03).