Hanseniaspora uvarum, a non-Saccharomyces cerevisiae species, has a crucial effect on the aroma characteristics of fruit wines, thus, attracting significant research interest in recent years. In this study, H. uvarum–Saccharomyces cerevisiae mixed fermentation was used to ferment Rosa roxburghii Tratt, blueberry fruit wine, and plum fruit wines using either a co-inoculated or a sequentially inoculated approach. The three fruit wines’ volatile aroma characteristics were analyzed by headspace–solid-phase microextraction–gas chromatography-mass spectrometry (HS–SPME–GC–MS). The results showed that the mixed inoculation of H. uvarum and S. cerevisiae reduced the alcoholic content of Kongxinli fruit wine. Moreover, H. uvarum–S. cerevisiae fermented Rosa roxburghii Tratt, blueberry, and plum fruit wines and further enriched their flavor compounds. The overall flavor characteristics of sequentially inoculated fruit wines differed significantly from those fermented with S. cerevisiae alone, although several similarities were also observed. Sequential inoculation of H. uvarum and S. cerevisiae positively affected the mellowness of the wine and achieved a better harmony of the overall wine flavors. Therefore, H. uvarum–Saccharomyces cerevisiae mixed fermentation can improve the complexity of the wines’ aromatic composition and empower them with a unique identity. In particular, H. uvarum–Saccharomyces cerevisiae blueberry wine produced by mixed fermentation had the widest variety and content of aroma compounds among the fermented wines. Therefore, H. uvarum–Saccharomyces cerevisiae mixed-fermentation inoculation in the three fermented fruit wines significantly increased the aroma compound variety and content, thus, enriching their aroma richness and complexity. This study is the first comparative evaluation of the aroma characteristics of different fruit wines fermented with a mixed inoculation of H. uvarum and S. cerevisiae and provides a preliminary guide for these fruit wines produced with non-Saccharomyces yeast.

Understanding how leaf maturity affects the flavor attributes of green tea is crucial for optimizing harvest timing and processing strategies. This study comprehensively characterized the flavor profiles of Fudingdabai green teas at three distinct leaf maturity stages—single bud (FDQSG), one bud + one leaf (FDMJ1G), and one bud + two leaves (FDTC2G)—using a multimodal approach integrating electronic nose, electronic tongue, HS-GC-IMS, relative odor activity value (rOAV) evaluation, and machine learning algorithms. A total of 85 volatile compounds (VOCs) were identified, of which 41 had rOAV > 1. Notably, 2-methylbutanal, 2-ethyl-3,5-dimethylpyrazine, and linalool exhibited extremely high rOAVs (>1000). FDQSG was enriched with LOX (lipoxygenase)-derived fresh, grassy volatiles such as (Z)-3-hexen-1-ol and nonanal. FDMJ1G showed a pronounced accumulation of floral and fruity compounds, especially linalool (rOAV: 7400), while FDTC2G featured Maillard- and phenylalanine-derived volatiles like benzene acetaldehyde and 2,5-dimethylfuran, contributing to roasted and cocoa-like aromas. KEGG (Kyoto Encyclopedia of Genes and Genomes) analysis revealed significant enrichment in butanoate metabolism and monoterpenoid biosynthesis. Random forest–SHAP analysis identified 20 key flavor markers, mostly VOCs, that effectively discriminated samples by tenderness grade. ROC–AUC validation further confirmed their diagnostic performance (accuracy ≥ 0.8). These findings provide a scientific basis for flavor-driven harvest management and the quality-oriented grading of Fudingdaibai green tea.

Rosa roxburghii Tratt (RRT) is esteemed for its unique aroma and nutritional value. Analyzing RRT juice samples from four elevations using GC–MS and GC-O, 99 volatile compounds were identified with 37 exhibiting aroma activity. 29 compounds including aldehydes, alcohols, and terpenes, were key contributors to RRT's aroma, based on high OAVs. Aroma recombination and omission tests confirmed 18 key aroma compounds in RRT while 2,5-Dimethyl-4-methoxy-3(2H)-furanone, hexanal, furfuryl acetate, furaneol acetate, and benzaldehyde as critical aroma compounds. The σ-τ graph revealed additive interactions among primary aroma compounds, indicating synergistic effects on RRT's overall aroma profile. Longli produced the most fragrant RRT at the lowest elevation of the four producing areas.

Understanding how leaf tenderness influences flavor attributes in green tea is crucial for optimizing harvest timing and processing strategies. This study comprehensively characterized the flavor profiles of Fudingdabai green teas at three tenderness levels—single bud (FDQSG), one bud + one leaf (FDMJ1G), and one bud + two leaves (FDTC2G)—using a multimodal approach integrating electronic nose, electronic tongue, HS-GC-IMS, relative odor activity value (rOAV) evaluation, and machine learning algorithms. FDQSG was dominated by fresh, grassy, and herbal volatiles such as (Z)-3-hexen-1-ol and nonanal, suggesting active LOX pathways. FDMJ1G showed a metabolic surge in floral compounds, especially linalool (rOAV > 7400), along with minty and fruity notes. FDTC2G featured roasted and cocoa-like aromas due to enhanced Maillard reactions and phenylalanine metabolism. KEGG analysis revealed significant enrichment in butanoate metabolism and monoterpenoid biosynthesis. Random forest–SHAP analysis identified 20 key flavor markers, mostly VOCs, that effectively discriminated samples by tenderness grade. ROC–AUC validation further confirmed their diagnostic performance (accuracy > 0.8). These findings provide a scientific basis for flavor-driven harvest management and the quality-oriented grading of Fudingdaibai green tea.

Aroma characteristics are critical indicators for evaluating sauce-flavor Daqu quality. This study systematically compared physicochemical properties, enzyme activities, microbiomes, and flavor profiles of first-grade (GF) and second-grade (GS) aroma Daqu. GF had higher total acidity, amino nitrogen content, acid protease activity, a lower pH, and was correlated with enrichment of bacteria potentially associated with flavor precursor production such as Kroppenstedtia guangzhouensis and Kroppenstedtia eburnea. GS showed higher liquefying/cellulase activities and pH, and was associated with dominance by hydrolytic fungi such as Paecilomyces variotii and off-odor-related Oceanobacillus. HS-SPME-GC–MS combined with VIP and OAV analyses identified 11 differential volatile compounds. Aldehydes were strongly correlated with positive aroma grading and may serve as potential indicators associated with grade differentiation, while GS accumulated dimethyl trisulfide correlating with off-odors. The findings reveal the relationships between multi-omics characteristics and aroma grade differentiation of Daqu, and provide theoretical support for Daqu quality evaluation and production regulation.