Legendary fermented herbs: an ethnobotanical study of the traditional fermentation starter of the Chuanqing people in Northwestern Guizhou, China.

Background: Plants that contain brewing microorganisms are used in traditional fermentation starters, which are an essential part of local diet, nutrition, life, and health. Regionally, the plant species used and the microorganisms included in traditional fermentation starters are diverse, endowing local fermented drinks with different flavors and health benefits. However, related traditional knowledge has been scarcely documented or revealed.

Methods: An ethnobotanical survey was conducted in five towns of Nayong County in northwestern Guizhou, China. Snowball sampling, semi-structured interviews, free lists, and participatory observation were used to collect information on Jiuqu Plants (JPs) and jiuqu-making techniques. The PacBio platform was used to study the microbial community structure and diversity in the Chuanqing people's jiuqu.

Results: In total, 225 informants were interviewed, including 116 who provided plants and technological processes for making Chinese baijiu jiuqu (CBJ) and 139 who provided information about making fermented glutinous rice jiuqu (FGRJ). This study found that older people have more abundant knowledge about CBJ plants. Poaceae was found to be the dominant family used in making CBJ and FGRJ (7 species each). Compared to individual plant parts, the whole plant is most commonly used in two kinds of jiuqu (19.5% in CBJ and 22.6% in FGRJ). The Chuanqing people's jiuqu is used to treat dietary stagnation and indigestion. The highest relative frequency of citation of the CBJ plant was Ficus tikoua Bureau, and the counterpart of the FGRJ plant was Buddleja macrostachya Benth. The dominant bacterial species in jiuqu were Gluconobacter japonicus (YQ1, YQ4) and Pediococcus pentosaceus (YQ2, YQ3), and the dominant fungal species was Rhizopus oryzae.

Conclusion: For the first time, this study documents the unique traditional jiuqu knowledge and reveals the microbial mystery behind the FGRJ of the Chuanqing people. Therefore, this study encourages the use of online social media platforms in order to spread Jiuqu culture, the use of the new media wave in order to create multimedia databases, and also suggests that local communities should develop preservation intervention programs, in addition to nurturing the inheritors in order to prevent the disappearance of traditional Jiuqu knowledge. This research contributes to the conservation and demystification of the traditional jiuqu knowledge of the Chuanqing people and lays the foundation for further research on its microbiology, nutrition, and metabolomics.