title: Effect of artificial shading on the tannin accumulation and aromatic composition of the Grillo cultivar (Vitis vinifera L.).
abstract: BACKGROUND
  White wine quality, especially in warm climates, is affected by sunlight and heat stress. These factors increase the probability that ambering processes will occur and reduce the potential flavour compounds. This study aimed to investigate the effect of sunlight reduction on the accumulation of polyphenolic and aromatic compounds.
  
  
  RESULTS
  This study was conducted in a commercial vineyard containing V. vinifera L. cv Grillo. Opaque polypropylene boxes (100% shading) and high-density polyethylene (HDPE) net bags (50% shading) were applied at fruit set. The effect of the shaded treatments was compared to the exposed fruit treatment. The shaded treatments resulted in heavier berries and lower must sugar contents than the exposed treatments. Proanthocyanidins and total polyphenol levels were similar in the exposed and bagged grapes; however, the levels were always lower in the boxed fruit. At harvest, the highest aroma level was measured in the boxed fruits.
  
  
  CONCLUSIONS
  The boxed fruit had less sugar, fewer proanthocyanidins and more flavours than the exposed grapes.The reduction in flavanols reactive to p-dimethylamino-cinnamaldehyde as (+)-catechin equivalents and total skin proanthocyanidins is an important result for the white winemaking process. In addition, the higher level of aromatic compounds in shaded grapes at harvest is an important contribution to the development of different wine styles.
authors.forename: Pietro
authors.initials: P
authors.lastname: Scafidi
authors.forename: Antonino
authors.initials: A
authors.lastname: Pisciotta
authors.forename: Davide
authors.initials: D
authors.lastname: Patti
authors.forename: Pasquale
authors.initials: P
authors.lastname: Tamborra
authors.forename: Rosario
authors.initials: R
authors.lastname: Di Lorenzo
authors.affiliation: Department of Agricultural and Forest Sciences, Università degli Studi di Palermo, Viale delle Scienze 11 ed, H, Palermo 90128, Italy. mariagabriella.barbagallo@unipa.it.
authors.forename: Maria Gabriella
authors.initials: MG
authors.lastname: Barbagallo
mesh_terms: D005638:Fruit / Q000254:growth & development / Q000378:metabolism / Q000528:radiation effects; D006031:Glycosylation; D006841:Hydrocarbons, Aromatic / Q000378:metabolism*; D044945:Proanthocyanidins / Q000378:metabolism; D012995:Solubility; D013472:Sunlight; D013634:Tannins / Q000378:metabolism*; D013696:Temperature; D013729:Terpenes / Q000378:metabolism; D027843:Vitis / Q000502:physiology* / Q000528:radiation effects
chemical_list: D006841:Hydrocarbons, Aromatic; D044945:Proanthocyanidins; D013634:Tannins; D013729:Terpenes