The phenolic compounds and compositional quality of Chétoui virgin olive oil: Effect of altitude

The differences in the chemical composition of virgin olive oils (VOO) obtained from trees of the Chetoui variety cultivated at different altitudes in Tunisia were evaluated. All samples were harvested using the same controlled procedures and were submitted to a controlled processing in the same laboratory mill. Several analytical parameters such as fatty acid composition, amounts of phenols; o-diphenols and pigments were analyzed. All these parameters showed an important effect on the fatty acids and phenols content of the oils. The total phenol content was positively correlated with the altitude, ranging from 817.33 mg/kg (403 m) to 131.91 mg/kg (10 m). However, the results of the regulated parameters in the potential quality classified all the analyzed oils into the ‘‘extra virgin’’ category.Key words: Orchard elevation, total antioxidant capacity, phenolic compounds, quality index

Triacylglycerols Composition and Volatile Compounds of Virgin Olive Oil from Chemlali Cultivar: Comparison among Different Planting Densities

The present study focused on the comparison the chemical composition of virgin olive oil samples obtained from fruits of the main Tunisian olive cultivar (Chemlali) grown in four planting densities (156, 100, 69, and 51 trees ha−1). Despite the variability in the triacylglycerols and volatile compounds composition, the quality indices (free fatty acids, peroxide value, and spectrophotometric indices K232 and K270) all of the virgin olive oils samples studied met the commercial standards. Decanal was the major constituent, accounting for about 30% of the whole volatiles. Moreover, the chemical composition of the volatile fraction of the oil from fruits of trees grown at the planting density of 156, 100, and 51 trees ha−1 was also characterised by the preeminence of 1-hexanol, while oils from fruits of trees grown at the planting density of 69 trees ha−1 had higher content of (E)-2-hexenal (20.3%). Our results confirm that planting density is a crucial parameter that may influence the quality of olive oils

Composición, calidad y estabilidad oxidativa de aceite de oliva virgen procedente de algunas variedades salvajes seleccionadas de aceitunas (Olea europaea L. subsp. oleaster)

A study on the characterization of virgin olive oils from wild olives (Olea europaea L. subsp. oleaster) was conducted in order to define new cultivars which are welladapted to the Tunisian environment and yield high quality oils. The study was done during the crop years 2003/04, 2004/05 and 2005/06. The main analytical parameters of the oils were evaluated: fatty acid compositions, chlorophylls, carotenoids, tocopherols and phenolic compounds as well as their relationship with oxidative stability. The fatty acid composition of all the wild olive trees tested produced virgin olive oil which complies with commercial standards, as well as for their appreciable amounts of tocopherols and phenolic compounds. Tocopherol analysis by HPLC revealed the presence of α, β, γ and δ tocopherols in all the studied olive oils. Total tocopherol content was significantly influenced by the varietal factor. It ranged from 310 (SB12) to 780 mg/kg (H3). As for total tocopherols, the amount of each tocopherol varied according to genotype. α tocopherol is the most prominent, whereas β, γ and δ tocopherols are less represented. Results showed a clear influence of total phenols and o-diphenols on virgin olive oil stability (R = 0.905, 0.963 PEn este trabajo se han caracterizado los aceites obtenidos a partir de siete acebuches previamente seleccionados entre varias poblaciones de Olea europea L. Subsp. oleaster. El estudio se llevó a cabo durante las campañas de producción 2003/04, 2004/05 y 2005/06.Varios parámetros analíticos fueron evaluados: composiciones en ácidos grasos, pigmentos, tocoferoles, fenoles; así mismo, se investigó la relación de estos parámetros con la estabilidad de los aceites. Los resultados obtenidos mostraron que todas las muestras de frutos de acebuche produjeron aceites cuya composición de ácidos grasos, tocoferoles y compuestos fenólicos cumplió las normas comerciales para aceite de oliva virgen del Comité Oleícola Internacional. El análisis de los tocoferoles con el HPLC reveló la presencia de las formas α, β, γ y δ en todos los aceites de oliva estudiados. El contenido total de tocoferoles estuvo claramente influido por la variedad, oscilando entre 310 mg/kg en SB12 hasta 780 mg/kg en H3. La forma α de los tocoferoles fue la más importante mientras que de las formas β, γ y δ se hallaron menores contenidos. Los resultados indicaron una clara influencia de los fenoles y de los o-difenoles en la estabilidad de los aceites vírgenes de oliva (R = 0.905, 0.963 con P < 10-3, respectivamente), y una contribución mucho más baja de los tocoferoles (R = 0.568) y de los ácidos grasos (R = 0,563)

Agronomic and molecular analyses for the characterisation of accessions in Tunisian olive germplasm collections

In this study, a total of 14 agronomic traits, five AFLP primer combinations and ten SSR loci were used to describe and to classify a group of Tunisian olive genotypes into groups based on molecular profiles and agronomic traits. The analysis of variance of the agronomical data revealed significant differences among accessions for all measured traits. The mean phenotypic dissimilarity (0.34 with a range of 0.08-0.6) was low in comparison to dissimilarity calculated using AFLP (0.50 with a range of 0.16-0.70) and SSR markers (0.76 with a range 0.35-0.94). The correlation between the agronomical dissimilarity matrix and the matrices of genetic dissimilarity based on SSR and AFLP markers was very weak: 0.156 (p = 0.05) and 0.185 (p = 0.05), respectively. The SSR-AFLP dendrogram based on unweighted pair-group cluster analysis using Jaccard\u2019s index revealed that the genetic diversity was predominantly structured according to fruit size. A trend of clustering together of accessions originating from the same or adjacent regions was also observed. The data obtained can be used for the varietal survey and construction of a database of all olive varieties grown in Tunisia and providing also additional information that could form the basis for the rational design of breeding programs

Extractos de hojas de olivo de Chétoui: Influencia del tipo de disolventes sobre los compuestos fenólicos y su actividad antioxidante

The aim of this study was to investigate the influence of the solvent type on the extraction of phenolics and the antioxidant properties of the extracts obtained from Chétoui olive leaves. Extraction was conducted at room temperature using four solvents: deionized water (ddH2O), 80% methanol (80% MeOH), 70% ethanol (70% EtOH), and 80% acetone. Total phenols and total flavonoids were measured using the Folin-Ciocalteau and aluminum chloride colorimetric methods, respectively. The antioxidant properties have been determined by two scavenging activity methods, DPPH and ABTS. The total phenol and flavonoid contents of the olive leaf extracts (OLEs) ranged from 16.52 to 24.93 mg gallic acid g–1 DM and from 6.23 to 21.47 mg catechin g–1 DM, respectively. The IC50 values of DPPH varied from 0.17 to 0.97 mg mL–1 and the antioxidant activity values determined by ABTS (trolox equivalent antioxidant capacity) were between 629.87 and 1064.25 μmol TE g–1 DM. Our results revealed that extracting solvents have a significant influence on the antioxidant properties of olive leaves and that a methanol mixture is recommended for extracts with high levels of flavonoids and important antioxidant activities. Moreover, it was noticed that the trolox equivalent antioxidant capacity (TEAC) depends more on the flavonoids (r = 0.821) than on the total phenols (r = 0.399).El objetivo de este trabajo fue estudiar la influencia del disolvente usado en la extracción de los compuestos fenólicos y en las propiedades antioxidantes de los extractos obtenidos a partir de hojas de olivo procedente de la variedad Chétoui. La extracción se realizó a temperatura ambiente, usando cuatro disolventes: agua desionizada(ddH2O), metanol 80% (80% MeOH) , etanol 70% (70% EtOH), y acetona 80%. Los fenoles totales y los flavonoides totales se midieron usando los métodos colorimétricos con Folin-Ciocalteau y cloruro de aluminio, respectivamente. Las propiedades antioxidantes han sido determinadas por dos métodos: el DPPH y el ABTS. El contenido de fenoles totales y flavonoides de los extractos de hojas de olivo (OLEs) varió desde 16,52 hasta 24,93 mg de ácido gálico g–1 de materia seca y desde 6,23 hasta 21,47 mg de catequina g–1 de materia seca, respectivamente. Los valores de IC50 de DPPH varian de 0,17 a 0,97 mg mL–1 y los valores de la actividad antioxidante determinados por ABTS (capacidad antioxidante en equivalentes de trolox) se encuentran entre 629,87 y 1064,25 μmol TE g–1 de materia seca, respectivamente. Nuestros resultados revelaron que los disolventes de extracción tienen una influencia significativa en las propiedades antioxidantes de los extractos de hojas de oliva. El metanol se recomienda para los extractos con alto nivel de flavonoides y con actividades antioxidantes importantes. Además, se observó que la capacidad antioxidante en equivalente de trolox (TEAC) depende más de los flavonoides (r = 0,821) que de los fenoles totales (r = 0.399)

Características sensoriales de aceites de oliva virgen procedentes de cultivares tunecinos monovarietales e híbridos con variedades europeas

This paper describes a sensory analysis of olive oils from main Tunisian cultivars: Chemlali, Chétoui, Sradki, Sayali and Hor Kesra, and one Spanish cultivar: Arbequina. Some hybrids obtained from controlled crossings between Tunisian and European cultivars: Hd 031, Hd 034, Hd 038, Hd 039, Hd 044 & Hd 045, were also analysed. Sensory evaluation of oils was performed in order to evaluate their sensory profiles. A Duncan Test (a = 0,05) was applied using the data of each attribute and showed differences between analysed oils, pointing out the oil from the hybrids HD 044 for its bitter attribute. All collected data were also submitted to Cluster analysis, based on the similarity in Euclidian distances, showing the difference between the oil from hybrid HD 044 and the rest.Con el fin de definir su perfil organoléptico, se han evaluado sensorialmente seis aceites de oliva virgen procedentes de cinco cultivares establecidos en diferentes zonas de Túnez: Sayali, Sradki, Hor Kesra, Chétoui y Chemlali, y un cultivar de la provincia de Badajoz (España): Arbequina; así como los procedentes de seis cultivares híbridos igualmente establecidos en Túnez: Hd 031, Hd 034, Hd 038, Hd 039, Hd 044 y Hd 045. Un test de Duncan (a = 0,05), teniendo en cuenta las puntuaciones dadas a los diferentes atributos evaluados, permite observar diferencias entre los aceites estudiados, destacando la encontrada entre el aceite procedente del híbrido Hd 044 de los restantes por su nivel de amargo. Así mismo, un análisis de Cluster, muestra la similitud entre ellos, teniendo en cuenta esos mismos atributos, observándose una clara diferencia entre el aceite con origen en el híbrido Hd 044 y los restantes

Chétoui olive leaf extracts: influence of the solvent type on phenolics and antioxidant activities

The aim of this study was to investigate the influence of the solvent type on the extraction of phenolics and the antioxidant properties of the extracts obtained from Chétoui olive leaves. Extraction was conducted at room temperature using four solvents: deionized water (ddH2O), 80% methanol (80% MeOH), 70% ethanol (70% EtOH), and 80% acetone. Total phenols and total flavonoids were measured using the Folin-Ciocalteau and aluminum chloride colorimetric methods, respectively. The antioxidant properties have been determined by two scavenging activity methods, DPPH and ABTS. The total phenol and flavonoid contents of the olive leaf extracts (OLEs) ranged from 16.52 to 24.93 mg gallic acid g&lt;sup&gt;–1&lt;/sup&gt; DM and from 6.23 to 21.47 mg catechin g&lt;sup&gt;–1&lt;/sup&gt; DM, respectively. The IC50 values of DPPH varied from 0.17 to 0.97 mg mL&lt;sup&gt;–1&lt;/sup&gt; and the antioxidant activity values determined by ABTS (trolox equivalent antioxidant capacity) were between 629.87 and 1064.25 μmol TE g&lt;sup&gt;–1&lt;/sup&gt; DM. Our results revealed that extracting solvents have a significant influence on the antioxidant properties of olive leaves and that a methanol mixture is recommended for extracts with high levels of flavonoids and important antioxidant activities. Moreover, it was noticed that the trolox equivalent antioxidant capacity (TEAC) depends more on the flavonoids (r = 0.821) than on the total phenols (r = 0.399).&lt;br&gt;&lt;br&gt;El objetivo de este trabajo fue estudiar la influencia del disolvente usado en la extracción de los compuestos fenólicos y en las propiedades antioxidantes de los extractos obtenidos a partir de hojas de olivo procedente de la variedad Chétoui. La extracción se realizó a temperatura ambiente, usando cuatro disolventes: agua desionizada(ddH2O), metanol 80% (80% MeOH) , etanol 70% (70% EtOH), y acetona 80%. Los fenoles totales y los flavonoides totales se midieron usando los métodos colorimétricos con Folin-Ciocalteau y cloruro de aluminio, respectivamente. Las propiedades antioxidantes han sido determinadas por dos métodos: el DPPH y el ABTS. El contenido de fenoles totales y flavonoides de los extractos de hojas de olivo (OLEs) varió desde 16,52 hasta 24,93 mg de ácido gálico g&lt;sup&gt;–1&lt;/sup&gt; de materia seca y desde 6,23 hasta 21,47 mg de catequina g&lt;sup&gt;–1&lt;/sup&gt; de materia seca, respectivamente. Los valores de IC50 de DPPH varian de 0,17 a 0,97 mg mL&lt;sup&gt;–1&lt;/sup&gt; y los valores de la actividad antioxidante determinados por ABTS (capacidad antioxidante en equivalentes de trolox) se encuentran entre 629,87 y 1064,25 μmol TE g&lt;sup&gt;–1&lt;/sup&gt; de materia seca, respectivamente. Nuestros resultados revelaron que los disolventes de extracción tienen una influencia significativa en las propiedades antioxidantes de los extractos de hojas de oliva. El metanol se recomienda para los extractos con alto nivel de flavonoides y con actividades antioxidantes importantes. Además, se observó que la capacidad antioxidante en equivalente de trolox (TEAC) depende más de los flavonoides (r = 0,821) que de los fenoles totales (r = 0.399)