Establishing the processing factor and degradation kinetics of hexaconazole residues in vinification and its residual impact on wine quality and aroma characteristics by GCxGC-ToF/MS analysis

Abstract

Hexaconazole (HX), a triazole fungicide, is widely used for controlling mildews in commercial viticulture, and residues at harvest are a challenge. The pesticide residues in the harvested grapes may impact the grape and wine quality. In this study, we have investigated the fate of HX residues in the vinification with wine aroma and quality. HX was applied at the recommended dose (RD) and 10 times RD (10 RD). The HX residue dissipation exhibited first-order kinetics with a half-life of 3.5 and 2.5 days for RD and 10 RD, respectively. The processing factor from grape to wine ranged from 0.04 to 0.09, the transfer rate ranged from 2.46% to 6.47%. The HS-SPME-GCxGC-ToF/MS analysis revealed a significant impact on volatile organic compounds (VOCs). The concentration of key VOCs varied in control as esters (147.62 μg L−1), alcohols (144.81 μg L−1), acids (82.92 μg L−1) and in HX RD treated wines showed reduction in alcohols (111.32 μg L−1), esters (91.57 μg L−1) and acids (67.10 μg L−1). In 10 RD, alcohols, esters, acids were declined as 131.42 μg L−1, 118.65 μg L−1, and 75.73 μg L−1 respectively. In HX RD, 28 were up and 58 VOCs were down-regulated. 40 VOCs were up and 46 were down-regulated in HX 10 RD wine. The pathway enrichment analysis revealed impact of HX residues on glycolysis and pyruvate metabolism. Quality analysis showed variation in total flavonoids, phenols, and anthocyanin content. The results revealed that HX residues have a negative impact on wine aroma and metabolism during vinification.