Anthocyanin content and composition in four red winegrape cultivars (Vitis vinifera L.) under variable irrigation

Nikolaos Theodorou,Stefanos Koundouras,Maria Kyraleou,Eleftheria Zioziou,Nikolaos Nikolaou,Yorgos Kotseridis,Stamatina Kallithraka

doi:10.20870/oeno-one.2019.53.1.2366

Abstract

Aim: The aim of this study was to determine and compare anthocyanin content and profile under variable irrigation regimes in four red grape cultivars (Vitis vinifera L.), the Greek indigenous cvs. Agiorgitiko and Xinomavro, alongside Syrah and Grenache noir.Methods and results: Three irrigation treatments were applied in a 6-year-old vineyard comprising all four varieties in a block design, starting at bunch closure (E-L 32) through harvest of 2012 and 2013: full irrigation (FI) at 100% of crop evapotranspiration (ETc), deficit irrigation (DI) at 50% of ETc and non-irrigated (NI). The identification of the compounds was performed by HPLC. Results showed that, under the hot summer conditions of the Greek climate, the four cultivars had a similar response regarding vigor and yield parameters, with values increasing with water supply. Anthocyanin concentration was maximized under non-irrigated conditions in all cultivars, but anthocyanin profile and relative distribution of individual anthocyanins among irrigation treatments showed a strong cultivar effect.Conclusion: Xinomavro seemed to favor the synthesis of more stable forms of anthocyanins under limited water supply (acylated over non-acylated and tri-oxygenated & methoxylated on the B-ring over di-oxygenated & hydroxylated) while Agiorgitiko had an opposite behavior, which might imply a need for a different irrigation strategy.Significance and impact of the study: To the best of our knowledge, this is the first comparative report of anthocyanin composition and profile in berry skin, under contrasting water status, for the two most important red winegrapes of Greece.

Highlights

Anthocyanidins of grape berry skins play a key role in wine color intensity, hue and stability
In Vitis vinifera L. berries, anthocyanidins occur as 3-O-glucosides, substituted with two or three hydroxyl (-OH) and/or methoxyl (OCH3) groups in the side-ring (B) of the flavonoid structure
Under the summer conditions of the Greek climate, the four cultivars had a similar response regarding vigor and yield parameters, with values increasing with water supply

Summary

Introduction

Anthocyanidins of grape berry skins play a key role in wine color intensity, hue and stability. In Vitis vinifera L. berries, anthocyanidins occur as 3-O-glucosides (anthocyanins), substituted with two (di-oxygenated: cyanidin- and peonidin-3O-glucosides) or three (tri-oxygenated: delphinidin-, petunidin-, and malvidin-3-Oglucosides) hydroxyl (-OH) and/or methoxyl (OCH3) groups in the side-ring (B) of the flavonoid structure. It has been shown that the profile and structure (e.g. esterification) of skin anthocyanins have an important role in the anthocyanin interactions, such as self-association and co-pigmentation, thereby affecting the intensity and stability of red color in wine (Han and Xu, 2015; GonzálezManzano et al, 2008). Color intensity increases with the number of substituted groups on the Bring (di-oxygenated forms are more red while trioxygenated shift to blue) and with the replacement of hydroxyl by methoxyl groups (i.e. malvidin has the darkest color). Methoxylated anthocyanins (malvidin and peonidin) are more stable than hydroxylated ones to environmental and viticultural factors (Castellarin and Di Gaspero, 2007)

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Conclusion