title: Class-modeling approach to PTR-TOFMS data: a peppers case study.
abstract: BACKGROUND
  Proton transfer reaction-mass spectrometry (PTR-MS), in its recently developed implementation based on time-of-flight mass spectrometry (PTR-TOFMS), was used to rapidly determine the volatile compounds present in fruits of Capsicum spp.
  
  
  RESULTS
  We analyzed the volatile organic compounds emission profile of freshly cut chili peppers belonging to three species and 33 different cultivars. PTR-TOFMS data, analyzed with appropriate and advanced multivariate class-modeling approaches, perfectly discriminated among the three species (100% correct classification in validation set). VIP (variable importance in projection) scores were used to select the 15 most important volatile compounds in discriminating the species. The best candidates for Capsicum spp. were compounds with measured m/z of 63.027, 101.096 and 107.050, which were, respectively, tentatively identified as dimethyl sulfide, hexanal and benzaldehyde.
  
  
  CONCLUSIONS
  Based on the promising results, the possibility of introducing multivariate class-modeling techniques, different from the classification approaches, in the field of volatile compounds analyses is discussed.
authors.affiliation: Università degli Studi di Firenze, Dipartimento di Scienze delle Produzioni Agroalimentari e dell'Ambiente, 50019, Sesto Fiorentino (FI), Italy.
authors.forename: Cosimo
authors.initials: C
authors.lastname: Taiti
authors.forename: Corrado
authors.initials: C
authors.lastname: Costa
authors.forename: Paolo
authors.initials: P
authors.lastname: Menesatti
authors.forename: Diego
authors.initials: D
authors.lastname: Comparini
authors.forename: Nadia
authors.initials: N
authors.lastname: Bazihizina
authors.forename: Elisa
authors.initials: E
authors.lastname: Azzarello
authors.forename: Elisa
authors.initials: E
authors.lastname: Masi
authors.forename: Stefano
authors.initials: S
authors.lastname: Mancuso
mesh_terms: D002212:Capsicum / Q000737:chemistry* / Q000145:classification*; D016002:Discriminant Analysis; D005638:Fruit / Q000737:chemistry; D016018:Least-Squares Analysis; D013058:Mass Spectrometry / Q000379:methods*; D013045:Species Specificity; D055549:Volatile Organic Compounds / Q000032:analysis*
chemical_list: D055549:Volatile Organic Compounds
keywords: PLS-DA; VIP scores; chili pepper (Capsicum spp.); class modeling; proton transfer reaction-mass spectrometry; volatile organic compounds (VOC)