Caracterización de los aceites de oliva virgen producidos en la zona oleícola de Tierra de Barros

Abstract

Esta tesis utiliza los criterios de calidad y pureza como herramientas para caracterizar los aceites de oliva virgen de la zona oleícola de Tierra de Barros (Badajoz).

El protocolo experimental contempló cuatro tratamientos, correspondientes a las variedades: Morisca y Carrasqueña y al sistema de elaboración: Sistema Abencor y elaboración en Almazaras industriales en tres estados de maduración del fruto y en tres campañas oleícolas

Los criterios de calidad (grado de acidez, índice de peróxidos, prueba espectrofotométrica en el ultravioleta) se encontraban dentro de la normativa europea (Reglamento CEE nº 2568/91). La evaluación sensorial mostró en todas las campañas y estados de maduración diferencias significativas entre las dos variedades. El contenido fenólico total y de la estabilidad oxidativa de los aceites de oliva virgen mostraron una gran diferenciación varietal.

Se encontraron diferencias significativas entre variedades para algunos compuestos pertenecientes a la composición acídica, triglicérida, esterólica y en los dialcoholes triterpénicos eritrodiol+uvaol.

El contenido en pigmentos y los parámetros colormétricos del espacio CIELab presentaron diferencias significativas entre variedades.

En cuanto al sistema de elaboración, se encontraron diferencias significativas en algunos criterios de calidad (índice de peróxidos, K y amargor) y en compuestos fenólicos totales. Por último, se observó el efecto de la campaña oleícola sobre determinados parámetros en los aceites caracterizados. Los aceites de la campaña oleícola 2007/08 presentaron menor contenido de compuestos fenólicos y peor calidad sensorial.

This thesis uses the criteria of quality and purity as tools to characterize Virgin Olive Oils (VOO) produced in Tierra de Barros area, located in the South of the Vegas del Guadiana (Badajoz).

The experimental protocol included four treatments, corresponding to the varieties: Morisca and Carrasqueña and the system development: Abencor system and oils produced in industrial Mills.

The results obtained in the determination of the criteria quality (acidity, peroxide index, test in the ultraviolet spectrophotometric) of the samples studied were within European legislation at the moment in which the analyses were conducted (Regulation CEE nº 2568/91 and modifies). In general terms, the sensory evaluation of the data clearly showed that in all the campaigns and stage of maturation there were clear differences between the two varieties (Morisca and Carrasqueña) studied. In terms of the determination of the total phenolic content and oxidative stability of the VOO analyses, they showed an important varietal differentiation.

Significant differences among varieties were found for some compounds belonging to the acidic composition, to the triacylglycerol, to the sterolics and in the triterpenic dialcohols, eritrodiol and uvaol.

The content of chlorophylls and carotenoids showed a clear decrease throughout the ripening cycle, finding significant differences between varieties. Respect to colour, oils were less bright and more intense as the maturation cycle progressed. In addition, for all colorimetrics parameters of the CIELab space, significant differences were found between varieties.

In terms of the elaboration system, significant differences were found in some criteria of quality (index of peroxides, K and bitter) and total phenolic compounds. Finally, the effect of the oleic campaign in certain parameters in oils characterize was observed. 2007/08 campaing originated a decrease of phenolic compounds and a worse sensory quality because of the increase of the rainfall and further development of pest and diseases.