Characteristics of the Microbial Community in the Production of Chinese Rice-Flavor Baijiu and Comparisons With the Microflora of Other Flavors of Baijiu

Abstract

Rice-flavor baijiu is one of the four basic flavor types of Chinese baijiu. Microbial composition plays a key role in the classification of baijiu flavor types and the formation of flavor substances. In this study, we used high-throughput sequencing technology to study the changes of microbial community in the production of rice-flavor baijiu, and compared the microbial community characteristics during production of rice-, light-, and strong-flavor baijiu. The results showed that the species diversity of bacteria was much higher than that of fungi during the brewing of rice-flavor baijiu. The bacterial diversity index first increased and then decreased, while the diversity of fungi showed an increasing trend. A variety of major microorganisms came from the environment and raw rice materials; the core bacteria were Lactobacillus, Weissella, Pediococcus, Lactococcus, Acetobacter, etc., among which Lactobacillus was dominant (62.88–99.23%). The core fungi were Saccharomyces (7.06–83.50%) and Rhizopus (15.21–90.89%). Temperature and total acid content were the main physicochemical factors affecting the microbial composition. Non-metric multidimensional scaling analysis showed that during the fermentation of rice-, light-, and strong-flavor baijiu, their microbial communities formed their own distinct systems, with considerable differences among different flavor types. Compared with the other two flavor types of baijiu, in the brewing process of rice-flavor baijiu, microbial species were fewer and dominant microorganisms were prominent, which may be the main reason for the small variety of flavor substances in rice-flavor baijiu. This study provides a theoretical basis for the production of rice-flavor baijiu, and lays a foundation for studying the link between baijiu flavor formation and microorganisms.

Screening of Yeasts Isolated from Baijiu Environments for Producing 3-Methylthio-1-propanol and Optimizing Production Conditions

“…Therefore, we analyzed the adaptability of strain YHM-G to the environment regarding its range of growth temperatures and pH and tolerance to sugar, NaCl, ethanol and 3-Met ( Figure 1 ). The optimum growth temperature of strain YHM-G was 25 °C, similar to most yeasts found in previous reports, with a maximum growth temperature of 40 °C ( Figure 1 a), which was higher than most temperatures (20–40 °C) during the Baijiu production process [ 38 , 39 , 40 , 41 , 42 ]. Therefore, strain YHM-G can adapt well to the different temperatures used in Baijiu production.…”

Bacterial Diversity and Lactic Acid Bacteria with High Alcohol Tolerance in the Fermented Grains of Soy Sauce Aroma Type Baijiu in North China

“…It is these differences between the north and the south that make the microbiota vary greatly in different regions, in the fermented grains of the same types of spirit. The essence of baijiu brewing is the process of microbial growth and metabolite accumulation, while the flavor and quality of baijiu rely on the synergistic effects between populations of microflora [ 3 ], which give baijiu its different flavors.…”

“…The quality of baijiu is not only related to production technology, but also closely related to geographical environment, water quality, climate, choice of grain, and other factors [ 2 ]. Production in different regions and with different production processes leads to differences in the evolution of microbial flora in the process of fermentation, and therefore differences in the trace components and quality of the final distilled baijiu products [ 3 , 4 ].…”

The changes of microbial diversity and flavor compounds during the fermentation of millet Huangjiu, a traditional Chinese beverage

“…The aroma is the best characterized feature of Huangjiu, determined by diverse volatile flavor compounds, and over 900 different kinds of various volatile flavor compounds have been confirmed according Chen et al’s study, comprising primarily esters, alcohols, phenols, aldehydes, ketones and acids [ 14 , 15 ].Though the classification of Huangjiu varies according to region or aroma types, the production process could be generally divided into six major stages [ 3 , 15 – 17 ]: the pretreatment of raw materials (especially soaking in millet Northern Huangjiu, while glutinous rice steaming in Southern Huangjiu), sacccharification (primary fermentation), alcoholization (secondary fermentation), filtering, sterilizing and aging. In other words, almost all the aroma compounds have been achieved through the above complicated fermentation process with the help of raw materials and Qu (fermentation starter) [ 18 ], during which the microbial diversity plays the most critical and indispensable role [ 19 , 20 ]. Microbiota and flavor dynamics during Huangjiu brewing mainly refers to simultaneous saccharification fermentation [ 3 , 21 ].…”