title: Leaf removal and wine composition of Vitis vinifera L. cv. Nero d'Avola: the volatile aroma constituents.
abstract: BACKGROUND
  Defoliation is a cultural practice for crop management in grapevines and the benefits effects have been demonstrated. Here, the influence of 'early' leaf removal on the quality of Nero d'Avola wines was evaluated. Particular attention has been given to the volatile constituents responsible for the wine aroma but also to the total amount of polyphenolic compounds, anthocyanins and flavonoids.
  
  
  RESULTS
  'Early' defoliation was manually applied and compared with non-defoliated controls. The grapes were harvested at two different ripening times following their technological and phenolic maturity. Statistical quantitative differences occurred among the samples from the four trials (defoliated and control samples, both at two ripening times). Both the time of harvest and the vine leaf removal determined variation in the wine composition. A large number of volatile constituents were identified and quantified; the odour activity values (OAVs) were calculated. Basal leaf removal reduced pH and increased titratable acidity, total amount of anthocyanins, flavonoids, polyphenols and colour intensity in the wines from the first harvest. Results showed the increase of fermentation and varietal aromas in the defoliated wines from the first harvest. Limited differences occurred between the wines from defoliated and control vines relative to the second harvest. Principal components analysis, which was applied to compounds with OAVs ≥ 0.5, allowed the different compounds to be distinguished.
  
  
  CONCLUSIONS
  'Early' leaf removal can lead to a positive effect on the quality of Nero d'Avola under the environmental conditions in which the present study was undertaken but particular attention has to be given to the time of grape harvest. The results also demonstrate that 'early' defoliation can be applied to improve wine quality in the Mediterranean region, where there is a concentration of rainfall during winter, and nearly arid conditions and high temperatures during the summer.
authors.affiliation: University of Messina, Department of Chemical Science, 98166 Messina, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Verzera
authors.affiliation: University of Messina, Department of Chemical Science, 98166 Messina, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Tripodi
authors.affiliation: University of Messina, Department of Chemical Science, 98166 Messina, Italy.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Dima
authors.affiliation: University of Messina, Department of Chemical Science, 98166 Messina, Italy.
authors.forename: Concetta
authors.initials: C
authors.lastname: Condurso
authors.affiliation: Regional Institute of Wine and Oil, 90143 Palermo, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Scacco
authors.affiliation: University of Messina, Department of Chemical Science, 98166 Messina, Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Cincotta
authors.affiliation: Regional Institute of Wine and Oil, 90143 Palermo, Italy.
authors.forename: Dina Maria Letizia
authors.initials: DM
authors.lastname: Giglio
authors.affiliation: Regional Institute of Wine and Oil, 90143 Palermo, Italy.
authors.forename: Tanino
authors.initials: T
authors.lastname: Santangelo
authors.affiliation: Regional Institute of Wine and Oil, 90143 Palermo, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Sparacio
mesh_terms: D000383:Agriculture / Q000379:methods*; D000872:Anthocyanins / Q000032:analysis; D005285:Fermentation; D005419:Flavonoids / Q000032:analysis; D005638:Fruit / Q000737:chemistry*; D006801:Humans; D009812:Odorants / Q000032:analysis*; D010636:Phenols / Q000032:analysis; D018515:Plant Leaves / Q000737:chemistry; D059808:Polyphenols / Q000032:analysis*; D027843:Vitis / Q000737:chemistry*; D055549:Volatile Organic Compounds / Q000032:analysis*; D014920:Wine / Q000032:analysis*
chemical_list: D000872:Anthocyanins; D005419:Flavonoids; D010636:Phenols; D059808:Polyphenols; D055549:Volatile Organic Compounds
keywords: HS-SPME/GC-MS; Nero d'Avola wine; basal leaf removal grapevine; physical-chemical analyses; volatile constituents