Giacosa, S.

Paissoni, Maria Alessandra

R&#237

Rolle, L.

English

Río Segade, Susana

Institutional Research Information System University of Turin

07 January 2022AperTO - Archivio Istituzionale Open Access dell'Università di TorinoOriginal Citation:Grape seed flavanols extraction and mechanical-acoustic properties as influenced by maceration time and ethanolcontentPublisher: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/2318/1805555 since 2021-10-11T20:38:36ZGrape seed flavanols extraction and mechanical-acousticproperties as influenced by maceration time and ethanolcontentAIM: Grape  avanols are involved in wine quality markers such as in-mouth sensations and colourstability. In particular, seed  avanols are characterized by low molecular weight and high galloylationratio, which are correlated respectively with bitterness and astringency. Their release duringmaceration is derived from the seed hydration and the ethanol-driven disassembly of cell walls that ispromoted by maceration time. In this study, acoustic and mechanical parameters were tested toinvestigate the e ect of maceration length and ethanol content on seed  avanols extraction. Themagnitude of the changes observed in seeds hardness in the di erent maceration conditions wasevaluated in the attempt to establish correlations with the extracted compounds. METHODS: Pinotnoir seeds were macerated in a wine-like solution (pH 3.40, 5 g/L tartaric acid) with di erent ethanolcontent (0, 5, 10, 15 and increasing addition up to 15% v/v). After 3, 7, and 10 days, total polyphenols(A280), condensed tannins (methylcellulose assay),  avanol composition as mean degree ofpolymerization (mDP), and monomeric content by HPLC were determined in the resulting solutions.Mechanical and acoustic parameters of macerated seeds were evaluated through compression test byinstrumental texture analysis. RESULTS: Seed tannins extraction was in uenced by both ethanol andmaceration time, in di erent extent depending on the speci c compound. In all macerations, an initialseed deformation together with a loss of elasticity was reported. As well, seed hardness (as seed breakforce, N) increased in all macerations except for 15% ethanol samples that showed a signi cantdecrease. In accordance, some acoustic parameters (as average acoustic energy, dB) increasedsigni cantly during maceration, and this last parameter was positively correlated with totalpolyphenols and condensed tannins extractions. CONCLUSIONS: Initial ethanol content andmaceration length in uenced  avanols richness and composition in the maceration extract. However,limited di erences in both phenolic composition and texture parameters were found between thesamples with no ethanol content and gradually-increasing alcohol strength.Authors: Maria Alessandra Paissoni – University of Torino, Italy,Susana RÍO SEGADE, University ofTorino, Italy Luca ROLLE, University of Torino, Italy Simone GIACOSA, University of Torino, ItalyEmail: mariaalessandra.paissoni@unito.it (mailto:mariaalessandra.paissoni@unito.it)Keywords: grape seeds, tannins, maceration, texture analysis, mechanical-acoustic properties( https://ives-openscience.eu/ives-conference-series/macrowine-2021/)(https://ives-openscience.eu/ives-conference-series/)Copyright© 2018 - IVES open science (https://ives-openscience.eu/)

Grape seed flavanols extraction and mechanical-acoustic properties as influenced by maceration time and ethanol content

https://iris.unito.it/bitstream/2318/1805555/1/Paissoni-et-al.-Macrowine2021-8096.pdf

Grape seed flavanols extraction and mechanical-acoustic properties as influenced by maceration time and ethanol content

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