Comprehensive study on the degradation of ochratoxin A in water by spectroscopic techniques and DFT calculations
Open Access
- 27 June 2019
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in RSC Advances
- Vol. 9 (34), 19844-19854
- https://doi.org/10.1039/c9ra02086a
Abstract
Ochratoxin A (OTA) is one of the most important dietary risk factors and is classified as a possible carcinogen to humans. Assessing the conditions to remove it from foodstuffs in a simple and effective way is of the utmost importance. OTA behaviour in water in the pH range 1.0–12.5 was elucidated to investigate the conditions for irreversible toxicity inactivation of OTA. The results indicate that four forms, from neutral to trianionic, intervene depending on the pH. pKa1,2 were rigorously established by independent spectroscopic techniques to overcome the scarcity of literature. Then, Density Functional Theory (DFT) calculations were used to determine the most probable degradation mechanism and this was confirmed by fluorescence spectroscopy. At pH 12.5, hydrolyzation of the lactone ring starts in less than one hour, but only after two hours does the degradation process lead to fragmentation. After one week this process is not yet completed. The reaction products occurring upon re-acidification were also investigated. OTA degradation is still reversible if acidic conditions are promptly restored, yielding again a hazardous molecule. However, degradation becomes irreversible after fragmentation. This finding suggests proceeding with due caution if a base is exploited to remove the toxin.Funding Information
- Università degli Studi di Torino
This publication has 61 references indexed in Scilit:
- Impact of pH on the Stability and the Cross-Reactivity of Ochratoxin A and CitrininToxins, 2013
- Theoretical analysis on alkaline hydrolysis mechanisms of N-(2-methoxyphenyl) benzamideComputational and Theoretical Chemistry, 2011
- Ochratoxin A: General Overview and Actual Molecular StatusToxins, 2010
- Analytical methods for determination of mycotoxins: A reviewAnalytica Chimica Acta, 2009
- CHIH-DFT determination of the molecular structure infrared spectra, UV spectra and chemical reactivity of three antitubercular compounds: Rifampicin, Isoniazid and PyrazinamideJournal of Molecular Modeling, 2007
- Multilinear Models: Applications in SpectroscopyStatistical Science, 1992
- Protein-binding of Ochratoxin A and Its Extractability from Proteinous FoodFood Hygiene and Safety Science (Shokuhin Eiseigaku Zasshi), 1985
- Studies on OchratoxinsCRC Critical Reviews in Toxicology, 1973
- Structural requirements for ochratoxin intoxicationLife Sciences, 1972
- The effect of ochratoxin A on glycogen storage in the rat liverToxicology and Applied Pharmacology, 1968