title: Harvest date effects on aroma compounds in aged Riesling icewines.
abstract: BACKGROUND
  Riesling icewine is an important product of the Ontario wine industry. The objective of this study was to characterize concentrations in aroma compounds in aged icewines associated with three harvest dates (H1, H2, H3) using stir bar sorptive extraction-gas chromatography-mass spectrometry and to make inferences, where appropriate, with respect to their roles in potential wine quality.
  
  
  RESULTS
  Delaying harvest decreased concentrations of many odorants, but increased many critical odor-active compounds; e.g. 1-octen-3-ol, ethyl benzoate, ethyl octanoate, cis-rose oxide, and β-ionone. H1 wines had higher concentrations of four aldehydes, three alcohols, nine esters, seven terpenes, γ-nonalactone, p-vinylguaiacol, β-damascenone, and 2-furanmethanol. However, many of these compounds, with some exceptions, have relatively high odor thresholds. Fourteen compounds were above their odor thresholds, including decanal, 1-octen-3-ol, phenylethyl alcohol, four ethyl esters, cis-rose oxide, linalool, γ-nonalactone, p-vinylguaiacol, ethyl cinnamate, β-damascenone, and 1,1,6-trimethyl-1,2-dihydronaphthalene. H3 wines contained higher concentrations of highly odor-active compounds, e.g. 1-octen-3-ol, cis-rose oxide, and β-ionone. Only phenylethyl alcohol [H3 odor activity value (OAV) = 0.33 (honey, spice, rose)] and linalool [H3 OAV = 0.92 (floral, lavender)] had H3 OAVs < 1.
  
  
  CONCLUSIONS
  Early harvest increased many esters and aliphatic compounds, but delayed harvest appeared to substantially increase concentrations of several highly odor-active compounds. © 2016 Society of Chemical Industry.
authors.affiliation: Cool Climate Oenology & Viticulture Institute, Brock University, St. Catharines, Ontario, Canada L2S 3A1.
authors.forename: Ramsey
authors.initials: R
authors.lastname: Khairallah
authors.affiliation: Cool Climate Oenology & Viticulture Institute, Brock University, St. Catharines, Ontario, Canada L2S 3A1.
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Reynolds
authors.affiliation: Consumer Insights and Product Innovation, Vineland Research and Innovation Center, 4890 Victoria Avenue North, Box 4000, Vineland Station, Ontario, Canada L0R 2E0.
authors.forename: Amy J
authors.initials: AJ
authors.lastname: Bowen
mesh_terms: D015415:Biomarkers / Q000032:analysis / Q000378:metabolism; D000069599:Crop Production; D005285:Fermentation; D063427:Food Quality; D061353:Food Storage; D005638:Fruit / Q000737:chemistry* / Q000254:growth & development / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D039821:Monoterpenes / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism; D045792:Norisoprenoids / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism; D009812:Odorants; D009864:Ontario; D025341:Principal Component Analysis; D012441:Saccharomyces cerevisiae / Q000254:growth & development / Q000378:metabolism; D013997:Time Factors; D015854:Up-Regulation; D027843:Vitis / Q000737:chemistry* / Q000254:growth & development / Q000378:metabolism; D055549:Volatile Organic Compounds / Q000032:analysis* / Q000302:isolation & purification / Q000378:metabolism; D014920:Wine / Q000032:analysis* / Q000145:classification / Q000382:microbiology
chemical_list: D015415:Biomarkers; D039821:Monoterpenes; D045792:Norisoprenoids; D055549:Volatile Organic Compounds
keywords: gas chromatography; mass spectrometry; monoterpenes; norisoprenoids; odor activity