Bitelli, G.

Drocco, D.

Gerbi, V.

Giacosa, S.

Ortiz Jacob, D.

Paissoni, M. A.

R&#237

Rainoldi, A.

Rolle, L.

Scalzini, G.

English

Río Segade, Susana

Institutional Research Information System University of Turin

07 January 2022AperTO - Archivio Istituzionale Open Access dell'Università di TorinoOriginal Citation:What is the best time to harvest grape destined for whitering? Ripeness and dehydration length affect phenoliccomposition of Nebbiolo grapesPublisher:Terms of use:Open Access(Article begins on next page)Anyone can freely access the full text of works made available as "Open Access". Works made available under aCreative Commons license can be used according to the terms and conditions of said license. Use of all other worksrequires consent of the right holder (author or publisher) if not exempted from copyright protection by the applicable law.Availability:IVES – International Viticulture and Enology SocietyThis is the author's manuscriptThis version is available http://hdl.handle.net/2318/1805592 since 2021-10-11T20:40:29ZWhat is the best time to harvest grapes destined forwithering? Ripeness and dehydration length affect phenoliccomposition of Nebbiolo grapesAIM: Sfursat di Valtellina is a DOCG reinforced wine produced in Valtellina from partially withered redgrapes of Vitis vinifera L. cv. Nebbiolo. The grape ripeness degree and the dehydration process stronglyin uence the physicochemical characteristics of grapes [1, 2, 3]. In particular, grape skin and seedscontain several classes of phenolic compounds strictly associated with red wine quality, which aresigni cantly a ected by these factors [4]. The aim of this research is to assess the combined in uenceof di erent ripeness levels and withering rates on the standard chemical composition and phenolicpro le of winegrape in order to provide new insights and approaches to the management of withering,searching for the valorization of grape potentialities.METHODS: During a two-year study (vintages 2019 and 2020) three binomials have been tested: earlyharvest/long withering (EL), medium-term harvest/medium-term withering (MM) and lateharvest/short withering (LS). Grape samples of cv. Nebbiolo from two vineyards at di erent locations(Valtellina upper and lower valley) were harvested and placed into a typical ‘fruttaio’ dehydrationroom, following the wine type designation guidelines. Grape must composition, mechanicalparameters and extractable phenolic pro les (total polyphenols, total anthocyanins, total  avonoidsand methylcellulose tannin assay) of grape skins and seeds were studied before and after the witheringprocess.RESULTS: At the end of withering, EL thesis showed the highest values of sugars and acidity, and thelowest pH. The content of total polyphenols,  avonoids, and tannins in seeds showed a decreasingtrend by leaving the grapes on the plant longer, whereas their impact increased considerably afterwithering with respect to fresh samples, due to berry dehydration. Instead, the skin phenoliccompounds were less in uenced by harvest period, but their concentrations on grape weight increasedafter withering. Skin extractable anthocyanins experienced a distinct trend for the two vineyardsstudied: their concentration increased in withered samples from the upper-valley vineyard anddecreased in those from the lower-valley. The grapes mechanical properties may have in uenced thisaspect, as previously demonstrated [5]. Finally, the di erences highlighted between the threebinomials studied were more noticeable in vintage 2019 rather than in 2020, probably due to the higherrainfall in the  nal stage of grape ripening in vintage 2020.CONCLUSIONS: In this research, the combined e ect of ripeness degree and withering process lengthhave been studied. The results obtained shows that these two variables can be modulated according tothe desired oenological objective. In general, early/medium harvest and long/medium withering gavethe best results, particularly for seeds polyphenols, although the vineyard location and the weatherconditions of the year in uenced the withered grape phenolic characteristics.Authors: Giulia Scalzini – University of Torino, Italy,Maria Alessandra PAISSONI, University of Torino,Italy Simone GIACOSA, University of Torino, Italy Danilo DROCCO, Cantina Nino Negri, Italy AldoRAINOLDI, Casa Vinicola Aldo Rainoldi, Italy Diego ORTIZ JACOB, University of Torino, Italy GiovanniBITELLI, University of Torino, Italy Susana RÍO SEGADE, University of Torino, Italy Vincenzo GERBI,University of Torino, Italy Luca ROLLE, University of Torino, ItalyEmail: giulia.scalzini@unito.it (mailto:giulia.scalzini@unito.it)Keywords: postharvest withered grapes, phenolic compounds, withering process, sfursat di valtellina,sforzato, reinforced wines, special wines( https://ives-openscience.eu/ives-conference-series/macrowine-2021/)(https://ives-openscience.eu/ives-conference-series/)

What is the best time to harvest grape destined for whitering? Ripeness and dehydration length affect phenolic composition of Nebbiolo grapes

https://iris.unito.it/bitstream/2318/1805592/1/Scalzini-et-al.-Macrowine2021-8377.pdf

What is the best time to harvest grape destined for whitering? Ripeness and dehydration length affect phenolic composition of Nebbiolo grapes

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