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Chinese Baijiu is a famous fermented alcoholic beverage in China. Interactions between key microorganisms, i.e., Saccharomyces cerevisiae and Lactiplantibacillus plantarum , have recently been reported at specific temperatures. However, empirical evidence of their interactions at various temperatures during fermentation is lacking. The results of this study demonstrated that S. cerevisiae significantly suppressed the viability and lactic acid yield of L. plantarum when they were cocultured above 15 °C. On the other hand, L. plantarum had no pronounced effect on the growth and ethanol yield of S. cerevisiae in coculture systems. S. cerevisiae was the main reducing sugar consumer. Inhibition of lactic acid production was also observed when elevated cell density of L. plantarum was introduced into the coculture system. A proteomic analysis indicated that the enzymes involved in glycolysis, lactate dehydrogenase, and proteins related to phosphoribosyl diphosphate, ribosome, and aminoacyl-tRNA biosynthesis in L. plantarum were less abundant in the coculture system. Collectively, our data demonstrated the antagonistic effect of S. cerevisiae on L. plantarum and provided insights for effective process management in light-flavor Baijiu fermentation.

The fermentation process of Chinese Baijiu's fermented grains involves the intricate succession and metabolism of microbial communities, collectively shaping the Baijiu's quality. Understanding the composition and succession of these living microbial communities within fermented grains is crucial for comprehending fermentation and flavor formation mechanisms. However, conducting high-throughput analysis of living microbial communities within the complex microbial system of fermented grains poses significant challenges. Thus, this study addressed this challenge by devising a high-throughput analysis framework using light-flavor Baijiu as a model. This framework combined propidium monoazide (PMA) pretreatment technology with amplicon sequencing techniques. Optimal PMA treatment parameters, including a concentration of 50 μM and incubation in darkness for 5 min followed by an exposure incubation period of 5 min, were identified. Utilizing this protocol, viable microorganism biomass ranging from 8.71 × 10 6 to 1.47 × 10 8 copies/μL was successfully detected in fermented grain samples. Subsequent amplicon sequencing analysis revealed distinct microbial community structures between untreated and PMA-treated groups, with notable differences in relative abundance compositions, particularly in dominant species such as Lactobacillus , Bacillus , Pediococcus , Saccharomycopsis , Issatchenkia and Pichia , as identified by LEfSe analysis. The results of this study confirmed the efficacy of PMA-amplicon sequencing technology for analyzing living microbial communities in fermented grains and furnished a methodological framework for investigating living microbial communities in diverse traditional fermented foods. This technical framework holds considerable significance for advancing our understanding of the fermentation mechanisms intrinsic to traditional fermented foods.

Ethyl carbamate (EC), a 2A carcinogen produced during the fermentation of foods and beverages, primarily occurs in distilled spirits. Currently, most studies focus on strategies for EC mitigation. In the present research, we aimed to screen strains that can degrade EC directly. Here, we report two Candida ethanolica strains (J1 and J116), isolated from fermented grains, which can reduce EC concentrations directly. These two yeasts were grown using EC as the sole carbon source, and they grew well on different carbon sources. Notably, after immobilization with chitosan, the two strains degraded EC in Chinese Baijiu by 42.27% and 27.91% in 24 h (from 253.03 ± 9.89 to 146.07 ± 1.67 and 182.42 ± 5.05 μg/L, respectively), which was better than the performance of the non-immobilized strains. Furthermore, the volatile organic compound content, investigated using gas chromatography-mass spectrometry, did not affect the main flavor substances in Chinese Baijiu. Thus, the yeasts J1 and J116 may be potentially used for the treatment and commercialization of Chinese Baijiu.

Baijiu is a traditional spirit with high reputation in the Chinese community, and whisky, on the other hand, is a renowned spirit in Western culture, with both contributing a major proportion to the consumption and revenue in the global spirit market. Interestingly, starting with similar raw materials, such as grains, diverse production methods lead to different organoleptic profiles. In addition, such enormous attention they attract renders them as a crucial part in food and the related industry. Therefore, great efforts are made in improving product quality and optimizing production processes, such as flavor enhancement, facility development, and deep utilization of byproducts. Given the huge impacts and great involvements of these spirits in the general food industry, research focusing on either spirit is of referential significance for other relevant fields. With the aim of facilitating such collaboration, this review discusses the current research status, in a comparative manner, of both spirits in respect to key production processes-oriented sensory and flavor analysis, deep utilization of byproducts, and spirit-derived functional food investigations. Finally, the internal correlations based on the abovementioned criteria are identified, with research prospects proposed., Competing Interests: The authors declare no conflicts of interest.