Affiliation:
1. Department of Agricultural Sciences, Division of Vine and Wine Sciences University of Naples Federico II Avellino Italy
2. Division of Food Science and Technology, Department of Agricultural Sciences University of Naples Federico II Portici Italy
3. Dipartimento per la Innovazione nei Sistemi Biologici, Agroalimentari e Forestali (DIBAF) University of Tuscia Viterbo Italy
Abstract
AbstractBACKGROUNDPostharvest dehydration affects the metabolism of grapes, impacting odorous secondary metabolites and therefore the features of the corresponding passito wines – high‐quality products with winemaking practices linked to specific territories and related autochthonous grape varieties. Water loss and temperature conditions are the main variables of the dehydration process. This study assessed how they impacted the patterns of free and glycosylated volatile organic compounds (VOCs) of the exocarp (pulp) and epicarp (skin) in Nebbiolo and Aleatico, a neutral and semi‐aromatic red grape variety, respectively. Dehydration parameters were set in tunnel conditions, and VOCs were quantitatively analyzed by solid phase extraction–gas chromatography–mass spectrometry.RESULTSFor Nebbiolo grapes, weight loss had a greater impact on free volatiles than dehydration temperature, with a 20% weight loss increasing total VOCs in both exocarp and epicarp. Low temperature (10 °C) significantly increased (P < 0.05) the glycosylated VOCs' terpene content. In Aleatico grapes, weight loss was key in modulating free volatiles, with 30% weight loss and 15 °C leading to significant increases in VOCs, especially exocarp terpenes, acids and benzenoids. More stressful dehydration (30% weight loss at 25 °C) resulted in higher aroma precursor concentrations.CONCLUSIONThese findings can assist passito wine production in preserving varietal aromas of original grapes trough optimized dehydration conditions, preventing sensory homologation occurring because of strong uncontrolled dehydration. They can also promote optimization of energy consumption, thus fostering financial and environmental sustainability. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.