The metabolism and accumulation of flavor compounds in Chinese Baijiu are driven by microbiota succession and their inter-related metabolic processes. Changes in the microbiome composition during Baijiu production have been examined previously; however, the respective metabolic functions remain unclear. Using shotgun metagenomic sequencing and metabolomics, we examined the microbial and metabolic characteristics during light-flavor Baijiu fermentation to assess the correlations between microorganisms and their potential functions. During fermentation, the bacterial abundance increased from 58.2% to 97.65%, and fermentation resulted in the accumulation of various metabolites, among which alcohols and esters were the most abundant. Correlation analyses revealed that the levels of major metabolites were positively correlated with bacterial abundance but negatively with that of fungi. Gene annotation showed that the Lactobacillus species contained key enzyme genes for carbohydrate metabolism and contributed to the entire fermentation process. Lichtheimia ramosa, Saccharomycopsis fibuligera, Bacillus licheniformis, Saccharomyces cerevisiae, and Pichia kudriavzevii play major roles in starch degradation and ethanol production. A link was established between the composition and metabolic functions of the microbiota involved in Baijiu fermentation, which helps elucidate microbial and metabolic patterns of fermentation and provides insights into the potential optimization of Baijiu production.

Fennel and dill are widely used as food additives owing to their various biological activities, such as antioxidants, antimicrobials, food-preservatives, and seasoning capacities. Herein, the nutritional composition and essential oil (EO) chemical profiles of fruits, umbels, stalks, and roots from one dill and two fennel cultivars were evaluated. The fruits had the highest content of crude protein (≥15%), crude fat (≥8%), and phosphorus (≥0.5%), and exhibited the highest total energy (≥20 MJ/kg) and EO yield (≥2%). Moreover, estragole (86.56% in Fdf), anethole (71.17% in Fhf), fenchone (16.74% in Fhf), limonene (50.19% in Agf), and carvone (42.41% in Agf) were the main components of the EOs generated from the fruits. The chemical profiles of EOs in the roots were significantly different from those of the aerial parts of the fennel and dill; thus, the roots and aerial parts could be distinguished based on myristicin (Variable Importance in Projection (VIP) = 1.90399) and apiol (VIP = 1.85922). The EO components of the aerial parts varied remarkably, and the chemical markers for differentiating these three cultivars were anethole (VIP = 1.36571), estragole (VIP = 1.30292), and carvone (VIP = 1.11947). Overall, our results provide a noteworthy chemical basis for further development of fennel and dill, especially as food additives.