RESUMEN
Caracterización y variación estacional de la calidad del aceite de oliva virgen de las variedades Throumbolia y Koroneiki del Sur de Creta.Aceite de oliva virgen extra fue producida con aceitunas de las dos principales variedades cultivadas en la región de Rethymnon en la isla de Creta denominadas "Throumbolia" y "Koroneiki". La primera es una variedad muy famosa debido a la falta de amargor natural de su fruto, mientras que la última es la variedad más común de aceitunas cultivada en el norte de Grecia. La aceitunas fueron cosechadas en tres estados sucesivos de maduración de acuerdo al color de su piel y el aceite de oliva virgen extra fue extraído en una almazara experimental a 30ºC. El indice de peróxides, la absorción UV, la acidez, el contenido en ácidos grasos y los polifenoles totales fueron medidos y los contenidos de tyrosol, hydroxytyrosol 3,4-DHPEA-EDA, p-HPEA-EDA y 3,4-DHPEA-EA fueron determinados por HPLC. La fracción de esteroles y el perfil de los componentes volátiles fueron analizados por GC y SPME GC/MS, respectivamente. El aceite de olovas de Throumbolia presentó un contenido extremadamente más alto de β-sitosterol y ácido linoleico (n6) que la variedad koroneiki. La concentración del ácido linoleico decrecio en ambas variedades, a diferencia del ácido oleico que presentó un incremento al mismo tiempo. Además, el contenidode OH-tyrosol fue más alto, mientras que el contenido de 3,4-DHPEA-EDA y los fenoles totales fueron más bajo, en aceite de oliva de Throumbolia que en el aceite de oliva producido por la variedad Koroneiki. En general, diferencias significativas fueron observadas en todos los parámetros entre los aceites de oliva producidos por las dos variedades durante las diferentes etapas de maduración.
PALABRAS CLAVE: Calidad del aceite de oliva virgen -
-The present study reported for the first time the evolution of some minor compounds (sterols and aliphatic alcohols) composition of four Algerian olive oils according to the cultivar and the maturity stage during the season (2013/2014). Olive samples were collected during eight different harvesting dates. The studied cultivars were Chemlal, Aghenfas, Buichret and Mekki. Ten sterolic compounds, triterpene dialcohols (erythrodiol þ uvaol) and seven fatty alcohols were identified and characterized. The results showed a decreasing level of total sterols, b-sitosterol, triterpenic dialcohols, total aliphatic alcohols, tetracosanol (C24), and an increasing level of D 5 -avenasterol according to the maturity process. Linear discriminant analysis (LDA) enabled the classification of the studied varieties on the basis of analytical data and a correct classification rate of 96.5% and 88.6% was achieved using the original and cross validation method respectively. The most discriminating variables have been: cholesterol, campestanol, D 7 -stigmastenol, D 7 -avenasterol, clerosterol, alcohol C22, alcohol C25, alcohol C27.
In the Mediterranean basin, a large number of olive varieties are present. This poses a series of problems concerning germplasm characterization and management. In addition, there is a problem arising from the existence of homonyms and synonyms. This makes cultivar identification very difficult and complex. Microsatellites or simple sequence repeat (SSR) are locus-specific codominant markers showing a high degree of polymorphism and multiple alleles per locus. Their high informativeness makes them the markers of choice in genetic diversity studies. This work presents the results of molecular characterization and identification of 20 Tunisian olive varieties using 10 SSR markers. All the SSR amplification products were sequenced to determine the number of repeats and the range of allele size. The number of alleles per SSR varied from three to six and the average heterozygosity rate ranged from 30% to 95%. Hierarchical classification of varieties base on similarity measures and clustering was globally consistent with the grouping of varieties by end use and phenotypic characteristics. The result is that varieties having the same name were found to have a clonal relationship. Paternity analysis showed also clone relationships between varieties not known to be related.
Acrylamide (ACR) is one of the most important contaminants occurring in foods heated at high temperatures. The aim of this study is to investigate the protective efficacy of extra virgin olive oil (EVOO), a main component of the Mediterranean diet, against nephrotoxicity induced by ACR. Rats have received by gavage during 21 days either ACR (40 mg/kg body weight) or ACR-associated with EVOO (300 μl) or only EVOO (300 μl). Acrylamide induced nephrotoxicity as evidenced by an increase in malondialdehyde (MDA), hydrogen peroxide (H2O2), protein carbonyls (PCOs) and a decrease in glutathione, non-protein thiols (NPSHs), and vitamin C levels. Activities of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx) were also decreased. Lactate dehydrogenase (LDH) activity, creatinine, urea, and uric acid, urinary volume and creatinine clearance levels were modified. EVOO supplementation improved all the parameters indicated above. Kidney histoarchitecture confirmed the biochemical parameters and the beneficial role of EVOO. EVOO, when added to the diet, may have a beneficial role against kidney injury by scavenging free radicals and by its potent antioxidant power.
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