Linking volatile compounds and aroma perception in macerated white wines: An integrated GC-MS and sensory approach

Abstract

Fermentative and post-fermentative maceration applied to white grapes has been traditionally used in Georgian winemaking and recently gained wider international interest. Scientific data on the chemical and sensory characteristics of these wines remain limited. This study focuses on the volatile composition of macerated white wines in relation to sensory perception. A total of 36 commercial Italian monovarietal white wines were selected from five cultivars (‘Arneis’, ‘Catarratto’, ‘Erbaluce’, ‘Malvasia Istriana’, ‘Vermentino’), produced with different maceration regimes: non-macerated controls, short (≤ 3 days), medium (4-7 days), long (8-30 days) skin contact, and “orange” (> 1 month). Volatile organic compounds (VOCs) were identified and quantified by HS-SPME/GC-MS. Aroma sensory evaluation was performed by a trained expert panel using the Rate-All-That-Apply (RATA) method with 20 pre-selected descriptors. A similar behaviour was observed in all wines, independently of grape variety, for certain VOCs. Most medium-chain fatty acids (hexanoic, octanoic, decanoic, and dodecanoic acids) and their corresponding ethyl esters decreased even after short maceration. In contrast, ethyl lactate and ethyl acetate were higher in macerated wines (approximately 3-fold and 1.5-fold, respectively) compared to controls. Methyl salicylate concentrations rose with increasing maceration duration, with maximum values observed in “orange” wines. For volatile phenols, 4-vinylguaiacol showed a decrease in wines macerated for more than 4 days, whereas 4-ethylphenol and 4-ethylguaiacol exhibited an increasing trend even after short maceration, although not consistently across all samples. Sensory analysis showed that Citrus, Pineapple, and White flowers descriptors were more pronounced in control wines, while macerated wines were characterized by Prune, Dried fig, Clove, and Liqueur notes. White pepper was a distinctive attribute of “orange” wines. PCA clearly separated “orange”, controls, and short-macerated samples. Short-macerated wines were associated with terpenes, esters, phenylethyl alcohol, and β-damascenone, which are known to contribute to fruity and floral aromas, confirming the role of 1-3 days of maceration in intensifying varietal and fermentative aroma. Prolonged maceration was associated with spicy and dried-fruit aroma, possibly linked to ethyl phenols, ethyl lactate, ethyl acetate, and methyl salicylate.