title: Development of an SPME-GC-MS method for the specific quantification of dimethylamine and trimethylamine: use of a new ratio for the freshness monitoring of cod fillets.
abstract: BACKGROUND
  Fish is a highly perishable food, so it is important to be able to estimate its freshness to ensure optimum quality for consumers. The present study describes the development of an SPME-GC-MS technique capable of quantifying both trimethylamine (TMA) and dimethylamine (DMA), components of what has been defined as partial volatile basic nitrogen (PVB-N). This method was used, together with other reference methods, to monitor the storage of cod fillets (Gadus morhua) conserved under melting ice.
  
  
  RESULTS
  Careful optimisation enabled definition of the best parameters for extracting and separating targeted amines and an internal standard. The study of cod spoilage by sensory analysis and TVB-N assay led to the conclusion that the shelf-life of cod fillet was between 6 and 7 days. Throughout the study, TMA and DMA were specifically quantified by SPME-GC-MS; the first was found to be highly correlated with the values returned by steam distillation assays. Neither TMA-N nor DMA-N were able to successfully characterise the decrease in early freshness, unlike dimethylamine/trimethylamine ratio (DTR), whose evolution is closely related to the results of sensory analysis until the stage where fillets need to be rejected.
  
  
  CONCLUSIONS
  DTR was proposed as a reliable indicator for the early decrease of freshness until fish rejection. © 2015 Society of Chemical Industry.
authors.affiliation: ANSES, Laboratoire de Sécurité des Aliments - Département des Produits de la Pêche et de l'Aquaculture, Boulevard du Bassin Napoléon, 62200 Boulogne-sur-Mer, France.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Dehaut
authors.affiliation: ANSES, Laboratoire de Sécurité des Aliments - Département des Produits de la Pêche et de l'Aquaculture, Boulevard du Bassin Napoléon, 62200 Boulogne-sur-Mer, France.
authors.forename: Simon
authors.initials: S
authors.lastname: Duthen
authors.affiliation: Université du Littoral Côe d'Opale - ANSES, Équipe Biochimie des Produits Aquatiques, Boulevard du Bassin Napoléon, 62200 Boulogne-sur-Mer, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Grard
authors.affiliation: Université de Lille 1, Unité de Glycobiologie Structurale et Fonctionnelle, UGSF - Bâtiment C9, 59650 Villeneuve d'Ascq, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Krzewinski
authors.affiliation: Université de Lille 1, Laboratoire Paul Painlevé - UMR CNRS 8524, Cité Scientifique, 59650 Villeneuve d'Ascq, France.
authors.forename: Assi
authors.initials: A
authors.lastname: N'Guessan
authors.affiliation: ANSES, Laboratoire de Sécurité des Aliments - Département des Produits de la Pêche et de l'Aquaculture, Boulevard du Bassin Napoléon, 62200 Boulogne-sur-Mer, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Brisabois
authors.affiliation: ANSES, Laboratoire de Sécurité des Aliments - Département des Produits de la Pêche et de l'Aquaculture, Boulevard du Bassin Napoléon, 62200 Boulogne-sur-Mer, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Duflos
mesh_terms: D053000:Analytic Sample Preparation Methods; D000818:Animals; D001267:Atlantic Ocean; D004123:Dimethylamines / Q000032:analysis* / Q000737:chemistry; D005513:Food Inspection / Q000379:methods*; D063427:Food Quality; D061353:Food Storage; D005602:France; D048388:Gadiformes; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008744:Methylamines / Q000032:analysis* / Q000737:chemistry; D009584:Nitrogen / Q000032:analysis; D017747:Seafood / Q000032:analysis* / Q000191:economics; D012677:Sensation; D017673:Sodium Chloride, Dietary / Q000032:analysis; D052617:Solid Phase Microextraction
chemical_list: D004123:Dimethylamines; D008744:Methylamines; D017673:Sodium Chloride, Dietary; C034516:dimethylamine; C023336:trimethylamine; D009584:Nitrogen
keywords: DMA; PVB-N; QIM; SPME-GC-MS; TMA; TVB-N; fish freshness; storage assessment