Effect of Peel Removal Rate on the Quality of Orah Mandarin Wine

To address the problem that traditional peel removal results in orah mandarin wine lacking a distinctive flavor, this study systematically investigated the impacts of peel removal rates (100% as a control, 80%, 50%, and 0%) on the juice quality and the fermentation kinetics and flavor formation of wine. The results demonstrated that a peel removal rate of ≥ 80% led to the highest juice yield and effectively eliminated the inhibitory effect of the peel on wine fermentation. Retaining the peel significantly enhanced the brightness and yellow-green hue of both juice and wine (P < 0.05). A total of 96 aroma compounds were identified, 35 of which were common to orah juice and wine. In total, 28 compounds disappeared after fermentation, while 17 esters and 9 alcohols were generated during the fermentation process. The terpene content in orah mandarin wine fermented with peels was 23.28 to 92.88 times higher than that in the control wine. The analysis of the key aroma compounds (with an odor activity value (OAV) ≥ 1)) of the orah wine samples revealed that 80% peel removal treatment effectively retained the characteristic volatiles of orah mandarin, D-limonene, octanal, laevo-rose oxide, and (1R,5R)-carveol (the content of these compounds was 27.70% of that of the 0% peel removal group), with the total content of ethyl octanoate and octanoic acid increasing by 72.88% compared with the control group. Using the cutoff of variable importance in projection (VIP) score ≥ 1 and OAV ≥ 1, D-limonene, octanoic acid, ethyl octanoate, β-myrcene, 2-methyl-3-buten-2-ol, 3,3-dimethylallyl alcohol, linalool, anethole, α-terpineol, and eugenol were identified as the characteristic aroma compounds of orah wine fermented with peels, whereas isoamyl alcohol and phenylethanol as the characteristic aroma compounds of the control wine. Sensory evaluation revealed that the 80% peel removal treatment was superior to the other treatments in overall acceptability, taste quality, clarity and color, harmony, and preference. This study suggests that 80% peel removal treatment achieved an optimal balance between juice yield, fermentation efficiency, and flavor quality, providing a theoretical foundation for industrial orah mandarin winemaking.