Phenolic compounds in olive oil by solid phase extraction - Ultra performance liquid chromatography - Photodiode array detection for varietal characterization

An new method for the extraction of phenolic compounds from olive oil has been proposed before the chromatographic analysis by UPLC-PDA (Ultra-Performance Liquid Chromatography-PhotoDiode Array). Recoveries for 20 individual phenolic compounds were compared using three cartridges of solid-phase extraction including C-18, Diol, and DVB (DiVinylBenzene) based cartridges. Diol based cartridge produced the best retention efficiency. The optimized method uses a reduced amount of solvents and allows for the determination of most phenolics in oil samples in less than 10 min. A full discrimination among the most common olive oil varieties was achieved using the relative levels for specific phenolics in the sample. Therefore, based in this study, a fingerprint based on the relative levels for quercetin, luteolin, oleuropein and vanillic acid can be proposed to characterized varietal olive oils. In that way, a detailed composition about phenolic compounds of varietal olive oils would not be needed for discrimination purposes. (C) 2021 The Authors. Published by Elsevier B.V

Parámetros químicos y actividad antioxidante de aceitunas de mesa al estilo natural de color cambiante de la variedad Sigoise

A chemical characterization of turning color table olives of the Sigoise variety was made through their processing as natural-style. Polyphenols, sugars, tocopherols, fatty acids, and antioxidant activity in the olives were monitored throughout the elaboration process. Oleuropein, salidroside, hydroxytyrosol 4-glucoside, rutin, ligustroside and verbascoside showed a decrease of 16.90-83.34%, while hydroxytyrosol increased during the first months of brining. Glucose was consumed by 90% due to the metabolism of the fermentative microbiota. The tocopherol content remained stable during the process and only the α-tocopherol decreased. The fatty acids were not affected. The loss in antioxidant compounds resulted in a decrease in the percentage of DPPH radical inhibition from 75.91% in the raw fruit to 44.20% after 150 days of brining. Therefore, the turning color natural table olives of the Sigoise variety are a good source of bioactive compounds.La caracterización química de las aceitunas en salmuera de color cambiante de la variedad Sigoise se ha estudiado durante el proceso de elaboración, en particular la concentración de fenoles, azúcares, tocoferoles, ácidos grasos y la actividad antioxidante. La concentración de oleuropeína, salidrósido, hidroxitirosol 4-glucósido, rutina, ligustrósido y verbascósido disminuyó un 16,90-83,34% durante el primer mes en salmuera. El 90% de la glucosa fue consumida debido al metabolismo de la microbiota fermentativa. El contenido en tocoferoles se mantuvo constante durante el proceso y solo disminuyó el α-tocoferol. Los ácidos grasos no se vieron afectados. La pérdida de actividad antioxidante se tradujo en una disminución del porcentaje de inhibición del radical DPPH de un 75,91% del fruto fresco a 44,20% después de 150 días en salmuera. A pesar de todo, la aceituna color cambiante de la variedad Sigoise en salmuera es una buena fuente de compuestos bioactivos

Componentes fenólicos en aceites de oliva vírgenes monovarietales de Argelia

The high oxidative stability of virgin olive oil is related to its high monounsaturated/polyunsaturated ratio and to the presence of antioxidant compounds, such as tocopherols and phenols. In this paper, the isolation of phenolic compounds from virgin olive oil from several Algerian varieties was tested and discussed in order to know its potential uses and benefits. Quantification of phenolic and o-diphenolic substances was performed using the traditional Folin-Ciocalteau method and the sodium molybdate reaction, respectively. The qualitative and quantitative characterizations of phenolic compounds were carried out by HPLC. The experimental results show that tyrosol, hydroxytyrosol and 4-HBA (4-hydroxybenzoic acid) are the main individual phenolic compounds identified in the varieties studied. The varieties with large fruits (Grosse du Hamma, Aghenfas, Azeradj, Aguenaou, Aberkane, Bouchouk de Guergour, X-Aghenfas, Rougette de Guelma, Sigoise) are clearly distinguished from the varieties with medium-sized and small fruits by having the highest levels of individual phenolic compounds. Moreover, varieties with small fruits (Hamra, Chemlal, Boughenfas, Limli, Aimel and Mekki) presented the highest levels of oleuropein.La alta estabilidad oxidativa de los aceites de oliva vírgenes está relacionada con su alta relación de ácidos grasos monoinsaturados/poliinsaturados y con la presencia de componentes antioxidantes, como tocoferoles y polifenoles. En este trabajo se llevó acabo un aislamiento y cuantificación de compuestos fenólicos de aceites de oliva virgenes de variedades argelinas, con el fin de conocer sus potenciales usos y beneficios. La cuantificación de los componentes fenólicos y o-difenólicos se realizó por método tradicional de Folin-Ciocalteu y mediante la reacción con molibdato de sodio, respectivamente. Los compuestos fenólicos individuales cualitativos y cuantitativos en los extractos y en una mezcla estándar fueron determinados por HPLC. Los resultados experimentales muestran que el tirosol, hidroxitirosol y el 4-HBA (ácido 4-hidroxibenzoico) son los principales compuestos fenólicos individuales identificados en el conjunto de la población de las variedades estudiadas. Por otra parte, la población de las variedades con frutos grandes (Grosse du Hamma, Aghenfas, Azeradj, Aguenaou, Aberkane, Bouchouk de Guergour, X-Aghenfas, Rougette de Guelma, Sigoise) se distinguen claramente de las variedades con frutos medios y pequeños. Además, la población de variedades con frutos pequeños (Hamra, Chemlal, Boughenfas, Limli, Aimel y Mekki) presentó el nivel más alto en oleuropeína

Phenolic compounds in mono-cultivar extra virgin olive oils from Algeria

The high oxidative stability of virgin olive oil is related to its high monounsaturated/polyunsaturated ratio and to the presence of antioxidant compounds, such as tocopherols and phenols. In this paper, the isolation of phenolic compounds from virgin olive oil from several Algerian varieties was tested and discussed in order to know its potential uses and benefits. Quantification of phenolic and o-diphenolic substances was performed using the traditional Folin-Ciocalteau method and the sodium molybdate reaction, respectively. The qualitative and quantitative characterizations of phenolic compounds were carried out by HPLC.&#13; The experimental results show that tyrosol, hydroxytyrosol and 4-HBA (4-hydroxybenzoic acid) are the main individual phenolic compounds identified in the varieties studied. The varieties with large fruits (<i>Grosse du Hamma, Aghenfas, Azeradj, Aguenaou, Aberkane, Bouchouk de Guergour, X-Aghenfas, Rougette de Guelma, Sigoise</i>) are clearly distinguished from the varieties with medium-sized and small fruits by having the highest levels of individual phenolic compounds. Moreover, varieties with small fruits (<i>Hamra, Chemlal, Boughenfas, Limli, Aimel</i> and <i>Mekki</i>) presented the highest levels of oleuropein.<br><br>La alta estabilidad oxidativa de los aceites de oliva vírgenes está relacionada con su alta relación de ácidos grasos monoinsaturados/poliinsaturados y con la presencia de componentes antioxidantes, como tocoferoles y polifenoles. En este trabajo se llevó acabo un aislamiento y cuantificación de compuestos fenólicos de aceites de oliva virgenes de variedades argelinas, con el fin de conocer sus potenciales usos y beneficios. La cuantificación de los componentes fenólicos y o-difenólicos se realizó por método tradicional de Folin-Ciocalteu y mediante la reacción con molibdato de sodio, respectivamente. Los compuestos fenólicos individuales cualitativos y cuantitativos en los extractos y en una mezcla estándar fueron determinados por HPLC.&#13; Los resultados experimentales muestran que el tirosol, hidroxitirosol y el 4-HBA (ácido 4-hidroxibenzoico) son los principales compuestos fenólicos individuales identificados en el conjunto de la población de las variedades estudiadas. Por otra parte, la población de las variedades con frutos grandes (Grosse du Hamma, Aghenfas, Azeradj, Aguenaou, Aberkane, Bouchouk de Guergour, X-Aghenfas, Rougette de Guelma, Sigoise) se distinguen claramente de las variedades con frutos medios y pequeños. Además, la población de variedades con frutos pequeños (Hamra, Chemlal, Boughenfas, Limli, Aimel y Mekki) presentó el nivel más alto en oleuropeína

Effect of Spanish style processing on the phenolic compounds and antioxidant activity of Algerian green table olives

The study was carried out on seven Algerian olive cultivars to report the effect of Spanish style processing on individual and total phenolic compounds and the changes that occur in antioxidant capacity. The results indicate that the treatment leads to losses in phenolic contents which are cultivar dependent. Sigoise is the least affected variety (12.25%) and Azzeradj from Seddouk the most affected one (94.80%). The phenolic profile shows drastic changes after processing. Hydroxytyrosol is dominant in processed olives (14.42-545.42 mg·100 g-1) while oleuropein is the major phenolic compound in fresh olives (994.27 mg·100 g-1). As a consequence to the loss in phenolic content, substantial reductions in the antioxidant activities of the extracts are noted. They are estimated to be 13.12-92.75% in scavenging activity against the DPPH radical, 37.78-93.98% in reducing capacity, 59.45-97.94% in the hydrogen peroxide radical and 7.26-51.66% in the inhibition bleaching of β-carotene. Among the processed varieties, only Sigoise presented a positive value of RACI (relative antioxidant capacity index)

Olive oils from Algeria: Phenolic compounds, antioxidant and antibacterial activities

The phenolic compositions, antioxidant and antimicrobial activities against six bacteria of phenolic extracts of olive oil varieties from eleven Algerian varieties were investigated. The antioxidant activity was assessed by determining the scavenging effect on the DPPH and ABTS^.+ radicals. The antimicrobial activity was measured as a zone of inhibition and minimum inhibitory concentration (MIC) on human harmful and foodborne pathogens. The results show that total phenols was significantly (p < 0.05) correlated with DPPH (r = 0.72) and ABTS^.+ radicals (r = 0.76). Among the bacteria tested, <em>S. aureus</em> and to a lesser extent <em>B. subtilis</em> showed the highest sensitivity; the MIC varied from 0.6 to 1.6 mg·mL^-1 and 1.2 to 1.8 mg·mL^-1, respectively. The results reveal that Algerian olive oils may constitute a good source of antioxidant and antimicrobial agents.<br><br>Se ha estudiado la composición fenólica y las actividades antioxidante y antimicrobiana, contra seis bacterias, de extractos de aceites de oliva de once variedades argelinas. La actividad antioxidante se evaluó mediante la determinación del efecto captador de radicales de DPPH y ABTS^.+. La actividad antimicrobiana se midió como zona de inhibición y como concentración inhibitoria mínima (MIC) sobre bacterias perjudiciales humanas y agentes patógenos transmitidos por los alimentos. Los resultados mostraron que los fenoles totales está significativamente (p < 0,05) correlacionados con DPPH (r = 0,72) y los radicales ABTS^.+ (r= 0,76). Entre las bacterias ensayadas, <em>S. aureus</em> y, en menor grado <em>B. subtilis</em> mostraron la mayor sensibilidad; el MIC varió de 0,6 a 1,6 mg·mL^-1 y 1,2 a 1,8 mg·mL^-1 respectivamente. Los resultados muestran que los aceites de oliva argelinos pueden constituir una buena fuente de antioxidantes y agentes antimicrobianos