Open Access

ARTICLE

Field Supplements of Ultraviolet-B Radiation in Veraison and Pre-Harvest Differentially Modify the Phenolic Composition of Grape Skins and Wines

Raquel Hidalgo-Sanz, María-Ángeles Del-Castillo-Alonso, Laura Monforte, Rafael Tomás-Las-Heras, Encarnación Núñez-Olivera, Javier Martínez-Abaigar^*

Faculty of Science and Technology, University of La Rioja, Madre de Dios 53, Logroño, 26006, Spain

* Corresponding Author: Javier Martínez-Abaigar. Email:

(This article belongs to the Special Issue: Adaptation Mechanisms of Grapevines to Growing Environments and Agricultural Strategies)

Phyton-International Journal of Experimental Botany 2025, 94(11), 3453-3470. https://doi.org/10.32604/phyton.2025.070087

Received 08 July 2025; Accepted 06 October 2025; Issue published 01 December 2025

Abstract

Grapevine (Vitis vinifera L.) is one of the main crops worldwide, and ultraviolet-B (UV-B, 280–315 nm) radiation is emerging as a promising technical tool to enhance secondary metabolites that can contribute to the quality and health-promoting properties of both grapes and the resulting wines. However, few studies have assessed the effectiveness of UV-B supplements under field conditions. Here, we compared the effects of two different field UV-B treatments (a single supplement applied at pre-harvest, and a double supplement applied at both veraison and pre-harvest) on the phenolic composition of Tempranillo grape skins and the resulting wines. The double supplement induced stronger changes than the single supplement, with responses being more pronounced in grape skins than in wines. In skins, UV-B supplements significantly increased flavonols, phenolic acids, and flavanols, consistent with previous reports highlighting flavonols as the most reliable UV-B-responsive compounds in grape skins. In wines, the clearest responses were increases in anthocyanins and color intensity. Overall, UV-B supplements improved grape and wine quality, although skin responses were only partially transmitted to the wines. Moreover, wine responses were more unpredictable than skin responses, likely reflecting not only the UV-B–induced changes in grape skins but also the complex chemical interactions among phenolic compounds (and also with other metabolites) during vinification. Further experimentation, particularly in the long term, is required to optimize the application of UV-B supplements as a viticultural and enological practice.

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Keywords

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Supplementary Material

Supplementary Material File

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