Seasonal dynamics of microbiota and physicochemical indices in the industrial-scale fermentation of Sichuan Baoning vinegar

Exploring the role of Sichuan Baoning vinegar microbiota and the association with volatile flavor compounds at different fermentation depths

“…The abundance of Proteobacteria and Actinobacteriota was a little higher in the upper layer while that of Firmicutes was higher in the lower layer ( Figures 2A – C ). At the genus level, similar to our previous report ( Liu et al, 2022 ), Lactobacillus , Bacillus , and Acetobacter were the top 3 genera through the fermentation in both fermentation depths ( Figures 2D , E ), but the abundance of Lactobacillus (74.98%) and Bacillus (11.14%) was higher in the lower layer while the abundance of Acetobacter (7.94%) was higher in the upper layer ( Figure 2F ). On the first day of fermentation, Bacillus was the predominant (28.64%), followed by Lactobacillus (14.35%) and Streptomyces (14.11%), which was different from previous reports ( Liu et al (2021) ; Liu et al, 2022 ) and the reason might lie in the differences in environmental factors and microorganisms from materials, processing equipment, and surrounding environment.…”

“…At the genus level, similar to our previous report ( Liu et al, 2022 ), Lactobacillus , Bacillus , and Acetobacter were the top 3 genera through the fermentation in both fermentation depths ( Figures 2D , E ), but the abundance of Lactobacillus (74.98%) and Bacillus (11.14%) was higher in the lower layer while the abundance of Acetobacter (7.94%) was higher in the upper layer ( Figure 2F ). On the first day of fermentation, Bacillus was the predominant (28.64%), followed by Lactobacillus (14.35%) and Streptomyces (14.11%), which was different from previous reports ( Liu et al (2021) ; Liu et al, 2022 ) and the reason might lie in the differences in environmental factors and microorganisms from materials, processing equipment, and surrounding environment. Afterward, Lactobacillus was predominant, ranging from 70.83 to 91.23% in the upper layer and 77.13 to 90.24% in the lower layer, respectively, which was not in agreement with the results of Zhenjiang aromatic vinegar and Shanxi mature vinegar ( Huang et al, 2022 ; Kou et al, 2022 ).…”

“…Compared to liquid-state fermentation, solid-state fermentation involves more complex microbiota, leading to more abundant flavor ( Wu et al, 2019 ; Gao et al, 2022 ). However, in order to enhance production yield and efficiency, two-stage liquid–solid fermentation is also utilized by Chinese vinegar manufacturers ( Liu et al, 2022 ). Sichuan Baoning vinegar, as representative of Sichuan bran vinegar, is one of the four traditionally famous vinegars in China ( Chen et al, 2016 ).…”

“…Sichuan Baoning vinegar differs from other vinegars in the following aspects: use of uncooked wheat bran as the primary raw material and Daqu (great koji) incorporated with Chinese herbs as the saccharifying agent; complete solid-state fermentation; an open fermentation process, with saccharification, alcohol fermentation, and acetic acid fermentation carried out simultaneously. The lactic acid content in Baoning vinegar was higher, leading to a more soft taste ( Liu et al, 2022 ).…”

Monitoring of land use change in Zhengzhou City based on Google Earth Engine

“…Based on Landsat images, Gong Peng et al completed the long-term series mapping products of China's built-up areas from 1978 to 2017 over a 40-year time span, filling the gap of higher-resolution time-space consistent dynamic monitoring products for builtup areas [5]. Liu et al proposed a Normalized Urban Area Composite Index (NUACI) that uses the GEE platform from Landsat images from 1990 to 2010 to extract global urban lands, i.e., artificial coverings and structures such as pavements, concrete, bricks, stones, and other types of artificially impenetrable coverings [6].…”