Thermal stability study of ochratoxin a during roasting coffee (Coffea Arabica)

Castellanos-Onorio Olaya, Durand Noël, Gonzalez-Rios Oscar, Fontana Angélique, Schorr-Galindo Sabine, Suárez-Quiroz Mirna. 2013. Thermal stability study of ochratoxin a during roasting coffee (Coffea Arabica). In : Proceedings of the 24th International Conference on Coffee Science, San José, Costa Rica, 12th-16th November 2012 = Actes du 24ème Colloque scientifique international sur le café, San José, Costa Rica, 12-16 novembre 2012. ASIC. Paris : ASIC, 380-384. ISBN 978-2-900212-23-3 International Conference on Coffee Science. 24, San José, Costa Rica, 12 Novembre 2012/16 Novembre 2012.

Note générale : Diaporama n°B8 accessible sur internet : http://asic2012costarica.org/download/presentations/3-wednesday.zip

Résumé : Two samples of contaminated coffee (5.3 and 57.2 ppb of OTA) were roasted at 230°C using two methods: rotating cylinder (RC) and fluidized bed (FB). Samples were taken every 3 and 0.9 min from RC and FB respectively. Each sample was analyzed for OTA content. The results showed that the process by RC was more effective on OTA reduction than FB for a same degree of roasting with 67% OTA reduction against 36% for the medium roast. The thermal degradation rate of pure OTA and the OTA mixed with the components of coffee (5 sugars, 3 amino acids, caffeine and chlorogenic acids) were determined, showing that interactions took place dependent themselves on the conditions of pH and pKa values of the components tested, in this case by influencing by the reactivity and the rate of degradation of OTA. A transformation product (TP) was observed in the chromatograms obtained from the interaction of OTA with the components of coffee. A test of alkalinization and warming of pure OTA confirmed that the TP comes from the structural modification of the OTA molecule and is not a product of interaction with the natural components of coffee. The TP was purified to carry out its chemical elucidation. The chemical nature of compound transformation and spectroscopic data such as UV-Vis (?max: 237nm), the affinity with the mobile phase of the OTA, the analysis of alkalinization (OTA regeneration phenomenon and TP), the analysis of stable isotopes (SIDA's) and the mass spectrum (molecular ion M +: 420 m/z), suggest that the TP of OTA during the roasting process corresponds structurally to an analogue of OTA which retains its acidic carboxyl group and in accordance to fragmentation corresponds to the Hydroxi-Ochratoxin A (OH-OTA), as well as minor amounts of OTA and its isomers.

Classification Agris : Q03 - Contamination et toxicologie alimentaires
Q02 - Traitement et conservation des produits alimentaires

Auteurs et affiliations

• Castellanos-Onorio Olaya, Instituto Tecnologico de Veracruz (MEX)
• Durand Noël, CIRAD-PERSYST-UMR Qualisud (FRA) ORCID: 0000-0003-1627-6848
• Gonzalez-Rios Oscar, Instituto Tecnologico de Veracruz (MEX)
• Fontana Angélique, UM2 (FRA)
• Schorr-Galindo Sabine, UM2 (FRA)
• Suárez-Quiroz Mirna, Instituto Tecnologico de Veracruz (MEX)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/570883/)

Métriques

[ Page générée et mise en cache le 2024-04-06 ]