![]() ![]() The monovarietal wines from Corvina produced without withering have been described to be dominated by an unripe astringency and, at the same time, by a high relative contribution for surface smoothness in their astringency profile ( Piombino et al., 2020), and they have lower polyphenol levels and ethanol in comparison with most Italian red wines ( Arapitsas et al., 2020 Giacosa et al., 2021). The postharvest withering of Corvina grape berry is a common practice for the production of the Amarone wine. The rate of berry's water loss and the extent of metabolic changes including aroma compounds in Corvina, Corvinone and Rondinella grapes are quite different during the postharvest withering process ( D'Onofrio et al., 2019 Bellincontro et al., 2016). ![]() The appellation of origin controlled and guaranteed (DOCG) "Amarone della Valpolicella" is reserved for wines produced from autochthonous local cultivars including Corvina and/or Corvinone (from 45 % to 95 %), and Rondinella (from 5 % to 30 %), while up to 25 % can come from other red cultivars ( MIPAAF, 2019). The structure of the berry renders low resistance to dehydration and enables berries of some selected grape varieties to shrivel under a slow withering process and leads to the development of the typical organoleptic characteristics of Amarone wine ( Accordini, 2013). The production of wines from partially dried grapes in the Veneto dates back to the times of the Ancient Romans. The current prolonged berry withering experiment revealed the timing of metabolite interconversions in the central metabolism and provided critical clues that link the concentration effect, protein degradation, and the onset of stress-like conditions in drying berries. Our network analysis revealed that increased metabolic network connectivity occurred during the middle stage of withering, thus reflecting more coordinated metabolite changes while reduced network connectivity at early and late stages indicates minimal metabolite perturbation during these stages. Unlike most of the identified metabolites, low molecular weight flavanols exhibited a consistent pattern of decline during the withering period. Stress-associated amino acids such as proline, serine, ethanolamine, and leucine accumulated significantly during the mid and late stages of the drying process while phosphorylated glucose and fructose, sucrose, kestose and resveratrol increased massively across time. Principal component analysis of both GC-MS and LC-MS datasets revealed three distinct phases of post-harvest withering early (day 0–28), mid (day 35–66) and late (day 69–108) stages. The temporal pattern of metabolic changes and time-series relationship between various classes of metabolites were investigated on berries sampled at 23-time points. Metabolic analysis was performed using GC-MS and LC-MS on Corvina berry dehydrated for up to 108 days. The grape berry withering process is often seen as a means to concentrate the constituents of the berry via water removal, however, recent molecular studies have indicated that the reprogramming of biosynthetic pathways that impart the unique aroma and flavour of the final wine also occur. ![]()
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