https://doi.org/10.17113/ftb.63.03.25.8804

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Impact of Fruit Zone Leaf Removal on Anthocyanin Stability in Wine During Bottle Ageing

Marina Pavlović^1*#, Zoran Zorić^1# Šime Marcelić¹, Maja Repajić², Name SurnamIva Šikuten^3,4 and Darko Preiner^3,4

¹University of Zadar, Department of Ecology, Agronomy and Aquaculture, Trg kneza Višeslava 9, 23000 Zadar, Croatia

²University of Zagreb Faculty of Food Technology and Biotechnology, Pierottijeva 6, 10000 Zagreb, Croatia

³University of Zagreb Faculty of Agriculture, Svetošimunska cesta 25, 10000 Zagreb, Croatia

⁴The Centre of Excellence for Biodiversity and Molecular Plant Breeding, Svetošimunska 25, 10000 Zagreb, Croatia

Copyright © 2024 This is a Diamond Open Access article published under CC-BY licence. Copyright remains with the authors, who grant third parties the unrestricted right to use, copy, distribute and reproduce the article as long as the original author(s) and source are acknowledged.

Article history:

Received: 31 July 2024

Accepted: 20 May 2025

Keywords:

red wine, anthocyanins stability, phenolic compounds, wine aging, Mediterranean climate

Summary:

Research background. Anthocyanins, the most abundant pigments in red wines, play an important role in the visual aspect of wine sensory properties. However, due to their unstable nature, their ability to polymerize with tannins is important for colour stability. Their content varies with grapevine variety, growing conditions, viticultural and winemaking practices. Leaf removal, a common viticultural practice, enhances anthocyanin accumulation in red grapevines, and partial fruit zone leaf removal at different phenological stages can significantly influence the anthocyanin content of grapes and wine. This two-year study examined how two different timings of fruit zone leaf removal at different phenological stages on the initial anthocyanins content in wine and their stability during aging in Merlot, Syrah and Cabernet Sauvignon wines grown in a Mediterranean climate.

Experimental approach. Partial leaf removal was performed during flowering (LRF) and during vérasion (LRV) and compared with an untreated control. Wines obtained from all treatments and varieties were bottled two months after the end of fermentation, and then stored and matured in cellar conditions for one year. To determine the influence of different times of leaf removal on the concentration of anthocyanins and their stability in the wine, wines were analyzed immediately after bottling, followed by 6 and 12 months of storage. For the determination of all phenolic compounds, high-performance liquid chromatography (HPLC) was used.

Results and conclusions. Leaf removal treatment increased the concentration of anthocyanins in all three cultivars. The obtained results showed that malvidin-3-O-glucoside (Mal-3-Glc) was the most abundant individual anthocyanin, while the most unstable anthocyanin was petunidin-3O-coumaroyl glucoside (Pet-3-Coum-Glc). Initial concentration of total anthocyanins in all wines were significantly affected by different conditions in two years of study, but with a significant impact of the defoliation treatments. Anthocyanin concentration decreased during the aging of the wine, and the degradation of anthocyanins ranged from 36 to 90 %. The stability of anthocyanins in wine was most influenced by aging time, while year and treatment had no influence. The concentration of total phenolic acids increased during wine aging while concentration of total flavonol glycosides (TFG) decreased in all wines except Merlot from 2016.

Novelty and scientific contribution. The results of this study contribute to a better understanding of the stability of increased levels of anthocyanins obtained by grapevine leaf removal practice in the vineyard, in wines during aging.

 
^#Both authors contributed equally