Characteristic flavor compounds and bacterial community of different gray sufu, a traditional Chinese fermented soybean curd

ABSTRACT

Gray sufu is a traditional Chinese fermented soybean curd, and its flavor is significantly influenced by bacterial community. In this study, volatile flavor compounds (VFCs) were examined by headspace solid‐phase microextraction (HS-SPME) in conjunction with gas chromatography and mass spectrometry (GC‐MS). Additionally, bacterial community was analyzed using high-throughput sequencing. The results showed that, a total of 156 VFCs were tentatively identified, in which 8 esters, 6 S/N-containing compounds, 3 alcohols, 3 aldehydes, 1 ketone and 3 other compounds were recognized as the main characteristic VFCs. The abundant S/N-containing compounds are the most important flavor characteristics of gray sufu. A total of 4 phyla and 12 genera were revealed as dominant bacteria. Firmicutes and Proteobacteria were the most abundant phylum, whereas Bacillus, Tetragenococcus and Lactococcus were the prevailing genera. According to the KEGG pathway annotation, amino acid metabolism (26.98%) was the highest metabolic pathway. Among them, aromatic amino acids metabolism accounted for the highest proportion, up to 34.94%. Correlation analysis showed that Lactobacillus, Tetragenococcus, Bacillus, Pseudomonas and Halanaerobium were the top five positive flavor-producing bacteria. The results will be helpful for understanding the fermentation mechanism of gray sufu and improving flavor quality by developing microbial regulation strategies.

KEYWORDS:

• Gray sufu
• volatile flavor compounds
• bacterial community
• functional predictive
• correlation analysis

Acknowledgement

The authors are grateful to Xuzhou University of Technology and State Key Laboratory of Functions and Applications of Medicinal Plants for supporting and providing necessary infrastructure. The authors also thank Miss Chunyan Li for the technical assistance of volatile flavor compounds determination.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Science and Technology projects of Xuzhou [award-id KC22057], N atural Science Foundation of the Jiangsu Higher Education Institutions [award-id 20KJB550013], North Jiangsu Science and Technology Project [XZ-SZ202051], National Natural Science Foundation of China [32102121] and the Research Projects of Xuzhou University of Technology [award-id XKY2019226; XKY2019228].