Microclimate Influence on Mineral and Metabolic Profiles of Grape Berries

• Published in: Journal of agricultural and food chemistry 2006-09, Vol.54 (18), p.6765-6775
• Main Authors: Pereira, G. E, Gaudillere, J.-P, Pieri, P, Hilbert, G, Maucourt, M, Deborde, C, Moing, A, Rolin, D
• Format: Article
• Language: English
• Subjects: amino acid composition; Amino Acids - analysis; Anthocyanins - analysis; berry position in cluster; Biological and medical sciences; Chemical Phenomena; Chemistry, Physical; Chromatography, High Pressure Liquid; defoliation; flavonols; Flavonols - analysis; Food engineering; Food industries; Fruit - chemistry; Fruit - growth & development; Fruit - metabolism; Fruit and vegetable industries; fruit composition; Fundamental and applied biological sciences. Psychology; Life Sciences; Light; Magnetic Resonance Spectroscopy; Microclimate; mineral content; Minerals - analysis; phenolic compounds; plant pigments; shade; solar radiation; spatial variation; Temperature; Vitis; Vitis vinifera; wine cultivars; wine grapes
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf061013k

The grape berry microclimate is known to influence berry quality. The effects of the light exposure of grape berry clusters on the composition of berry tissues were studied on the “Merlot” variety grown in a vineyard in Bordeaux, France. The light exposure of the fruiting zone was modified using different intensities of leaf removal, cluster position relative to azimuth, and berry position in the cluster. Light exposures were identified and classified by in situ measurements of berry temperatures. Berries were sampled at maturity (>19 Brix) for determination of skin and/or pulp chemical and metabolic profiles based on (1) chemical and physicochemical measurement of minerals (N, P, K, Ca, Mg), (2) untargeted 1H NMR metabolic fingerprints, and HPLC targeted analyses of (3) amino acids and (4) phenolics. Each profile defined by partial least-square discriminant analysis allowed us to discriminate berries from different light exposure. Discriminant compounds between shaded and light-exposed berries were quercetin-3-glucoside, kaempferol-3-glucoside, myricetin-3-glucoside, and isorhamnetin-3-glucoside for the phenolics, histidine, valine, GABA, alanine, and arginine for the amino acids, and malate for the organic acids. Capacities of the different profiling techniques to discriminate berries were compared. Although the proportion of explained variance from the 1H NMR fingerprint was lower compared to that of chemical measurements, NMR spectroscopy allowed us to identify lit and shaded berries. Light exposure of berries increased the skin and pulp flavonols, histidine and valine contents, and reduced the organic acids, GABA, and alanine contents. All the targeted and nontargeted analytical data sets used made it possible to discriminate sun-exposed and shaded berries. The skin phenolics pattern was the most discriminating and allowed us to sort sun from shade berries. These metabolite classes can be used to qualify berries collected in an undetermined environment. The physiological significance of light and temperature effects on berry composition is discussed. Keywords: Amino acids; flavonols; 1H NMR; HPLC; metabolic profiles; microclimate; partial least-square; temperature; Vitis vinifera