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Clonal differences and impact of defoliation on Sauvignon blanc (Vitis vinifera L.) wines: a chemical and sensory investigation

Šuklje, Katja, Antalick, Guillaume, Buica, Astrid, Langlois, Jennifer, Coetzee, Zelmari A, Gouot, Julia, Schmidtke, Leigh M, Deloire, Alain
Journal of the science of food and agriculture 2016 v.96 no.3 pp. 915-926
Vitis riparia, Vitis vinifera, acetates, canopy, clones, defoliation, gas chromatography-mass spectrometry, hexanols, microclimate, odors, rootstocks, vineyards, volatile compounds, wines
BACKGROUND: The aim of this study, performed on Sauvignon blanc clones SB11 and SB316, grafted on the same rootstock 101–14 Mgt (Vitis riparia × V. ruperstris) and grown at two adjacent vineyards, was two‐fold: (1) to study wine chemical and sensory composition of both clones within an unaltered canopy; and (2) to determine the effect of defoliation (e.g. bunch microclimate) on wine chemical and sensory composition. RESULTS: Orthogonal projection to latent structures discriminate analysis (OPLS‐DA) was applied to the concentration profiles of volatile compounds derived from gas chromatography–mass spectrometry data. The loadings directions inferred that 3‐isobutyl‐2‐methoxypyrazine (IBMP) discriminated control treatments (shaded fruit zone) of both clones from defoliation treatments (exposed fruit zone), whereas 3‐sulfanyl‐hexan‐1‐ol (3SH), 3‐sulfanylhexyl acetate (3SHA), hexanol, hexyl hexanoate and some other esters discriminated defoliated treatments from the controls. The OPLS‐DA indicated the importance of IBMP, higher alcohol acetates and phenylethyl esters, for discrimination of clone SB11 from clone SB316 irrespective of the treatment. Defoliation in the fruit zone significantly decreased perceived greenness in clone SB11 and elevated fruitier aromas, whereas in clone SB316 the effect of defoliation on wine sensory perception was less noticeable regardless the decrease in IBMP concentrations. CONCLUSION: These findings highlight the importance of clone selection and bunch microclimate to diversify produced wine styles. © 2015 Society of Chemical Industry