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The natural presence of OTA in wine has been reported worldwide. However, this is the first investigation that has demonstrated the co-occurrence of several ochratoxins in 51 red wines from Navarra (Spain) and 96 samples from 8 Mediterranean countries. This fact is partly due to the low limits of detection and quantification obtained. An HPLC-FLD analytical method was developed and validated for the simultaneous quantification of ochratoxin A (OTA), ochratoxin B (OTB) and their methyl and ethyl esters (methylochratoxin A (MeOTA), ochratoxin C (OTC), methylochratoxin B (MeOTB) and ethylochratoxin B (EtOTB)) in red wine. No samples exceeded the 2 µg/L maximum permitted by the EU for OTA in wine. Simultaneous occurrence of OTA and OTB were found in 100% of the samples. In addition, 90% of the Mediterranean wines presented OTC and the six ochratoxins were detected in 45%. OTA-OTB and OTA-OTC concentrations showed a very large positive association between each other. In general, levels were not influenced by the country of origin except in the case of Tunisia and Algeria, whose concentrations were statistically higher. Some factors that could affect the ochratoxin levels were investigated. In general, no significant differences were found between vintages. With the exception of OTA, no significant differences were observed between organic and traditional farming. Concentrations were positively correlated with temperature and inversely correlated with humidity and rainfall during the summer prior to grape harvesting. OTC transformation into OTA in red wine was also examined. The results obtained suggested that OTC hydrolyzed to OTA in wine.

Se ha realizado la cuantificación de ciertos metales de interés como Zn, Cu, Mn y Fe, mediante la técnica de espectroscopía de emisión atómica de plasma acoplado por inducción (ICP-AES), en muestras de vino a lo largo de su fermentación durante 345 días. Los resultados obtenidos muestran la disminución de las concentraciones de Cu y Fe con el tiempo de fermentación y que las concentraciones de Zn y Mn se mantienen estables en el mismo periodo de tiempo. Así mismo, se han llevado a cabo estudios electroquímicos de complejación con disoluciones tamponadas a pH 4 (similar al valor natural del vino) que contenían un ligando modelo, la catequina, con el fin de verificar la aplicabilidad de la técnica de voltamperometría de redisolución anódica de pulso diferencial al estudio de muestras acondicionadas a ese pH. Estos estudios han permitido establecer que la estequiometría de los complejos catequina:metal formados es 1:1 tanto para el Zn como para el Cu. El comportamiento electroquímico de una muestra de vino diluida y analizada de forma similar a la de estas disoluciones de ligando modelo, permite sugerir que una parte importante de los ligandos naturales presentes en el vino, capaces de complejar al Zn y al Cu, tiene una naturaleza muy similar a la de la catequina