Chemical properties of virgin olive oil from Iranian cultivars grown in the Fadak and Gilvan regions

The aim of this study is to evaluate the chemical compositions (total phenol, fatty acid, sterolic compounds) of Iranian virgin olive oil (Zard, Rowghani, Mari) cultivated in the Gilvan (Zanjan Province) and Fadak (Qom Province) regions. Total phenols were determined using the Folin-Ciocalteu assay. Fatty acid and sterol profiles were also analyzed using gas chromatography. In most cases, significant effects (<em>P</em> < 0.05) of cultivars and locations were detected by the chemical composition of the oil samples. The fatty acid analysis indicated that the Mari variety from Gilvan had high oleic/low linoleic acid content; therefore it is a highly resistant olive oil against oxidation. Furthermore, the high mean values of total sterols were also obtained for the Mari variety. The oil of the Zard variety from Gilvan had the maximum amount of phenols as a positive quality index. Therefore, the Mari variety, especially from Gilvan has been suggested as a superior cultivar compared to the Zard and Rowghani varieties.<br><br>El objetivo de este estudio fue evaluar la composición química (fenoles totales, ácidos grasos, y esteroles) de aceites de oliva virgen iranies (Zard, Rowghani, Mari) cultivados en las regions de Gilvan (provincia de Zanjan) y Fadak (provincia de Qom). Los fenoles totales se determinaron utilizando el método de Folin-Ciocalteu. Los perfiles de ácidos grasos y de esteroles se determinaron mediante cromatografía de gases. En la mayoría de los casos, existen diferencias significativos de los cultivares y los lugares detectados por la composición química (P < 0,05 ). El análisis de ácidos grasos indicó que la variedad Mari de Gilvan presenta una relación alta oleico/ linoleico; por lo tanto, es un aceite de alta resistencia contra la oxidación. Por otra parte, los valores medios altos de esteroles totales también fueron obtenidos para la variedad Mari. El aceite de la variedad Zard de Gilvan presentó la mayor cantidad de fenoles, considerado este valor como un índice de calidad positivo. La variedad Mari especialmente en Gilvan se sugeriere como un cultivar superior en comparación con las variedades Zard y Rowghani

Evaluation of extra-virgin olive oils shelf life using an electronic tongue-chemometric approach

Physicochemical quality parameters, olfactory and gustatoryretronasal positive sensations of extra-virgin olive oils vary during storage leading to a decrease in the overall quality. Olive oil quality decline may prevent the compliance of olive oil quality with labeling and significantly reduce shelf life, resulting in important economic losses and negatively condition the consumer confidence. The feasibility of applying an electronic tongue to assess olive oils usual commercial light storage conditions and storage time was evaluated and compared with the discrimination potential of physicochemical or positive olfactory/gustatory sensorial parameters. Linear discriminant models, based on subsets of 58 electronic tongue sensor signals, selected by the meta-heuristic simulated annealing variable selection algorithm, allowed the correct classification of olive oils according to the light exposition conditions and/or storage time (sensitivities and specificities for leave-one-out cross-validation: 8296 %). The predictive performance of the E-tongue approach was further evaluated using an external independent dataset selected using the KennardStone algorithm and, in general, better classification rates (sensitivities and specificities for external dataset: 67100 %) were obtained compared to those achieved using physicochemical or sensorial data. So, the work carried out is a proof-of-principle that the proposed electrochemical device could be a practical and versatile tool for, in a single and fast electrochemical assay, successfully discriminate olive oils with different storage times and/or exposed to different light conditions.The authors acknowledge the financial support from the strategic funding of UID/BIO/04469/2013 unit, from Project POCI-01-0145-FEDER-006984—Associate Laboratory LSRELCM funded by FEDER funds through COMPETE2020—Programa Operacional Competitividade e Internacionalização (POCI)—and by national funds through FCT—Fundação para a Ciência e a Tecnologia and under the strategic funding of UID/BIO/04469/2013 unit. Nuno Rodrigues thanks FCT, POPH-QREN and FSE for the Ph.D. Grant (SFRH/BD/104038/2014).info:eu-repo/semantics/publishedVersio

Influence of malaxation conditions on characteristic qualities of olive oil

While there has been considerable work examining the effect of extraction methods and malaxation conditions on different characteristics of olive oils, there have been few that deal with all the major aspects. Here we have evaluated three different extraction techniques and the influence of time and temperature during malaxation using a major Italian (cv. Coratina) and the main Cretan (cv. Koroneiki) cultivars. Standard characteristics were measured as well as detailed analyses of alcohols, steroids and phenolics were conducted. Quality was also assessed by Panel tests. The main variables were the total amount and composition of the phenolics. In turn, this influenced the oxidative stability and sensory quality. It was also clear that the cultivars behaved differently and this prevented general conclusions being made for all of the quality characteristics