## 2 Materials and Methods
### Enzyme Activity  
Grape berries were deseeded and ground to powder with liquid nitrogen for the determination of enzyme activities. The activities of enzymes, such as LOX, HPL, ADH, and AAT, were assessed using the method described by [PERSON] et al. (2018) with slight modifications. A 0.01 change in absorbance per minute per gram was defined as one enzyme activity unit (U), and LOX, ADH, and AAT activity was expressed as U/g fresh weight (FW).  
LOX: Sample powder (5.0 g) was mixed with 6 mL of pre-cooled 0.1 M phosphate buffer containing 1% Triton X-100, 0.35 M PVPP, and a pH of 6.8. The mixture was subjected to a temperature of \(-\)18 \({}^{\circ}\)C for 5 min. Following this, it was centrifuged at 4 \({}^{\circ}\)C, 10,000 r/min, and for 30 min. The resulting supernatant was collected as the crude enzyme solution. The reaction system comprised 25 \(\mu\)L of 10 mM sodium linoleate solution, 2.9 mL of 0.1 M phosphate buffer (pH 6.8), and 75 \(\mu\)L of crude enzyme solution. Using distilled water as a reference, the absorbance was measured at 234 nm. The timing commenced 30 s after the addition of crude enzyme solution and absorbance values were recorded at 15 s intervals for a total duration of 120 s.  
HPL: Sample powder (3.0 g) was added to 9 mL of 50 mM sodium acetate buffer (pH 5.0, 0.21% ascorbic acid, 0.5% Triton X-100). Subsequently, the mixture was cooled at \(-\)18 \({}^{\circ}\)C for 5 min then centrifuged for 30 min at 10,000 r/min and at 4 \({}^{\circ}\)C. The supernatant was collected and measured using an enzyme-linked immunosorbent assay kit (Jiwei Biological Technology Co., Ltd., Shanghai, China).  
ADH: Sample powder (3.0 g) was added to 9 mL of 0.1 M 4-morpholineethanesulfonic acid buffer (2 mM dithiothreitol, 1% PVPP, pH 6.5), cooled at \(-\)18 \({}^{\circ}\)C for 5 min, and centrifuged at 4 \({}^{\circ}\)C for 30 min at 10,000 r/min. The supernatant was then taken as the crude enzyme solution. The reaction system included 2.0 mL of 0.1 M 4-morpholineethanesulfonic acid buffer, 100 \(\mu\)L of 1.6 mM nicotinamide adenine dinucleotide solution, 200 \(\mu\)L of 80 mM acetaldehyde solution, and 0.2 mL of crude enzyme solution. Using distilled water as a reference, the absorbance was measured at 340 nm. Timing commenced 15 s after the addition of crude enzyme solution and the absorbance was measured every 30 s within 300 s.  
AAT: Sample powder (3.0 g) was mixed with 5 mL of 0.5 M Tris-HCL (pH 8.0, 0.1% Triton X-100, 0.3 mg PVPP), extracted in an ice bath for 20 min, and centrifuged at 12,000\(\times\)\(g\) r/min for 20 min. The supernatant was collected and used as the crude enzyme solution. The reaction system included 2.5 mL of 5 mM MgCl\({}_{2}\) solution, 150 \(\mu\)L of acetyl-CoA (0.5 M Tris-HCL, pH 8.0), 50 \(\mu\)L of 200 mM butanol solution (0.5 M Tris-HCL, pH 8.0), and 150 \(\mu\)L of crude enzyme solution. After 15 min in a 35 \({}^{\circ}\)C water bath with crude enzyme solution, 100 \(\mu\)L of 10 mM 5,5\({}^{\prime}\)-Dithiobis-(2-nitrobenzoic acid) was added. Using reaction solution without crude enzyme solution as a reference, the absorbance was measured at 412 nm. Timing began 15 s after the addition of crude enzyme solution, and absorbance values were recorded every 15 s for 120 s.