Effect of ambient sunlight intensity on the temporal phenolic profiles of Vitis Vinifera L. Cv. chardonnay during the ripening season-A field study

Abstract

Grape pbenolics are considered 10 hive a significant impact od nine quality, with their quantity and dynamic; being strongly influenced by environmental conditions. We investigated the effect of ambient sunlight on the temporal dynamics of phenolic-in cv. Cbardonnay under field conditions during the 2012 ripening season, from veraison until harvest. The phenolic profiles of the grapes were monitored at predefined time intervals by using nigh-pressure liquid chromatography (HPLC) and spectrophoiomeiric (OD) analysis. The obtained concentrations were correlated nith the average sunlight intensities preceding the sampling. No significant correlations were found between the hydroxycinnamic acid, bydroxybeuioic acid andstilbene content, in contrast with the strong relationships found between: (i)OD. "ii>T (u) catechin, • nl-fl. ii anols and (iv) total polyphenols and the fluctuating dos of ambient sunlight reaching the grapes throughout the ripening season. The light-dependent dynamics of several main phenolic compounds in cv. Cbardonnay during the ripening period could help to establish correlation models that increase the applicability of meteorological data in the assessment of optimal phenolic ripeness in modern viticulture.