Recent advances in biotechnology have ensured that one of the main olive tree by-products is olive leaf extract (OLE), a rich source in bioactive compounds. The aim of this work was to study the ...phenolic composition in different OLEs of three Tunisian varieties, namely, 'Sayali', 'Tkobri', and 'Neb Jmel'. The in vitro biodigestibility effect after 'Sayali' OLE addition to Californian-style 'Hojiblanca' table olives was also studied. This OLE contained bioactive molecules such as hydroxytyrosol, tyrosol, oleropeine, Procianidine B1 (PB1), and
-cumaric acid. These compounds were also found in fresh olives after OLE was added. Furthermore, from fresh extract to oral digestion, the detected amount of bioavailable phenol was higher; however, its content decreased according to each phase of gastric and intestinal digestion. In the final digestion phase, the number of phenols found was lower than that of fresh olives. In addition, the phenolic content of Californian-style 'Hojiblanca' table olives decreased during the in vitro digestion process. The antioxidant activity of this variety decreased by 64% and 88% after gastrointestinal digestion, being the highest antioxidant capacity found in both simulated gastric and intestinal fluid, respectively. The results show us that the 'Sayali' variety is rich in phenolic compounds that are bioavailable after digestion, which could be used at an industrial level due to the related health benefits.
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Olive leaves are one of the most prevalent by-products of the olive oil industry and may be exploited as a low-cost source of high-added-value phenolic compounds. The pharmaceutical, cosmetic, and ...food sectors are becoming more interested in the therapeutic effects attributed to these bioactive components in olive leaf extract. This work offers some indication of the chemical potentialities of oleasters leaf as a new source of functional food. Qualitative and quantitative compositional analysis revealed 14 major phenolic compounds among which oleuropein, hydroxytyrosol, apigenin 7-O-glucoside, tyrosol, epicatechin, and vanillic acid were identified. The bioactive compounds that presented the least concentration were gallic, vanillic,
p
-coumaric, and chlorogenic acids. Maximum concentrations were found for hydroxytyrosol, oleuropein, and luteolin-7-o-glucoside in wild olive leaves. Concerning the antioxidant activity, the oleaster leaves showed high antioxidant proprieties using ABTS (acide 2,2’-azino-bis-(3-éthylbenzothiazoline6-sulfonique) method. Chemometrics (principal component analysis (PCA) and dendrogram analysis) were applied to the quantitative phenolic compounds data, allowing good discrimination of the phenols according to their antioxidant activities. The oleaster leaves seem to be a source of antioxidants and can be an attractive tool for industrial uses.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The aim of this work was analyzing the use of olive leaf extracts (OLE) obtained from two local Tunisian olive tree cultivars 'Chemlali' and 'Sayali' to reduce the acrylamide in Californian-style ...black olives. The phenol profile, antioxidant, and antibacterial activity of the two OLE extracts were evaluated. The principal phenols found were hydroxytyrosol (1809.6 ± 25.3 mg 100 g
), oleuropein (2662.2 ± 38 mg 100 g
) and luteolin-7-O-glucoside (438.4 ± 38 mg 100 g
) presented higher levels in 'Sayali' variety. Small differences were observed between the two kinds of extracts used; the greatest activity of OLE was observed against
, with values up to 50% inhibition. The extract of 'Chemlali' cultivar was added to the Californian-style table olive, improving its phenol content and its antioxidant characteristics without negatively affecting its sensorial characteristics; these olives showed the highest firmness and proper quality characteristics. The gastrointestinal activity on the acrylamide concentration showed a partial degradation of this compound through the digestion, although the addition of the extract does not seem influence in its gastrointestinal digestion. These findings prove the usefulness of by-products to generate a high-quality added-value product, and this would also be relevant as a step towards a more sustainable, circular economy model.
The sterol profile of Tunisian virgin olive oils produced from Chétoui cultivar, the second main variety cultivated in the north of the country, grown under different environmental conditions, was ...established by gas chromatography using a flame ionisation detector. More than ten compounds were identified and characterised. As expected for virgin olive oil, the main sterols found in all Chétoui olive oils were β-sitosterol, Δ5-avenasterol, campesterol and stigmasterol. Cholesterol, 24-methylenecholesterol, clerosterol, campestanol, sitostanol, Δ7-stigmastenol, Δ5,24-stigmastadienol, and Δ7-avenasterol were also found in all samples, but in lower amounts. Most of these compounds are significantly affected by the geographical origin. The majority of the Chétoui virgin olive oils analysed respected EC Regulation No. 2568, and in all cases total sterol amounts were higher than the minimum limit set by legislation, ranging from 1017 to 1522mg/kg.
Two triterpenic dialcohols (erythrodiol and uvaol), were also detected besides the sterolic components. Their content was below the upper legal limit of 4% in all analysed samples, with a range from 1.2% to 3.2%. These results suggest that, besides the genetic factor, environmental conditions influence the sterolic fraction.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The selection of new olive cultivars with a good oil quality among feral olives may be considered as a way to diversify our olive genetic resources and to select new cultivars for oil production ...under Tunisian conditions. This study was carried out to determine phenolic and tocopherol compounds, pigments, oxidative stability, triacylglycerol, and fatty acid compositions of unstudied feral olive oils, and a comparison was made with the Chemlali cultivar, the most common Tunisian variety. Results demonstrated that the profiles of feral oils were distinctly different from those of cultivated Chemlali oil. All results indicate that there is a wide variability in the chemical characteristics of the studied oils. Our results showed that F3 feral olive oil was characterized by high mean values of total phenols (1073 mg kg
−1
) and oxidative stability (88.4 h). The cultivar genotype factors might explain variability in phenols (105–1074 mg kg
−1
), tocopherol (324–844 mg kg
−1
), C18:1 (57–78%), oxidative stability (26–105 h), and the profiles of triacylglycerol in investigated extra virgin olive oils (EVOOs). HPLC-ESI-MS analyses showed that F3 olive oil contains appreciable amounts of alcohols (399 mg kg
−1
) and high concentrations of secoiridoid derivatives (SID) (545 mg kg
−1
). Therefore, tocopherol analysis revealed the presence of α-, β-, γ-, and δ-tocopherols in all the studied olive oils. As for total tocopherols, the amount of each tocopherol varied according to genotype. α-tocopherol is the most abundant, whereas β-, γ-, and δ-tocopherols are less represented. Besides, the results demonstrated the great influence of total phenols and tocopherols on the stability of virgin olive oil (
R
2
= 0.9027,
R
2
= 0.901,
P
< 0.05, respectively). Additionally, the statistical analyses (PCA and HCA) can explain the variability of the oil composition according to the cultivar. The feral olive oils constitute a new edible oil source characterized richer in natural bioactive components.
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CEKLJ, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
En este estudio, dieciocho variedades de aceituna procedentes de España, de Francia, de Italia, de Grecia y de Argelia, cultivadas en la estación experimental del olivo de Boughrara (región árida de ...Túnez), fueron evaluadas para el rendimiento en aceite y la composición de ácidos grasos. El análisis de la varianza mostró diferencias significativas entre todas las variedades (p < 0,01). El análisis de "clusters" jerárquico clasificó las variedades en tres grandes grupos. El primer grupo incluía un subgrupo compuesto por siete variedades de aceituna Changlot Real, Koroneiki, Verdial de Vélez-Málaga, Coratina, Lechín de Granada, Cornezuelo y Leccino, que se caracterizan por su alto rendimiento en aceite, alto contenido en oleico y bajo contenido en ácidos palmítico y linoleico. Las composiciones de ácidos grasos de aceites provenientes de estas variedades se conforman con estándares internacionales y son mejores si las comparamos con la de Chemlali (el cultivo más abundante en Túnez). Finalmente, los ácidos grasos mayoritarios (palmítico (C16:0), oleico (C18:1) y linoleico (C18:2)) de nueve de los aceites de oliva virgen estudiados fueron comparados con los de las mismas variedades cultivadas en sus áreas originarias. A excepción de los aceites Koroneiki y Olivière que mostraron una composición de ácidos grasos inalterable y del aceite Cornezuelo en el que se observó un aumento del nivel de ácido oleico y un descenso del nivel de ácido linoleico, la mayoría de los aceites mostró disminución de ácido oleico y aumento de los porcentajes de ácido palmítico y linoleico, comparándolos con los obtenidos de las aceitunas cultivadas en sus lugares de origen.
In this study, eighteen olive varieties, originating from Spain, France, Italy, Greece and Algeria, and maintained at the olive experimental station of Boughrara (arid region of Tunisia) were evaluated for their oil yield and fatty acid composition. The analysis of variance revealed significant differences among varieties for all traits (p < 0.01). The Hierarchical Cluster Analysis (HCA) classified the varieties into three main groups. The first group included a subgroup which is composed of seven olive varieties (Cornezuelo, Verdial de Vélez-Málaga, Leccino, Coratina, Koroneiki, Lechín de Granada and Changlot Real) characterized by high oil yield with high oleic, low palmitic and linoleic acid contents. The fatty acid compositions of the oils from these varieties comply with international standards and show more beneficial characteristics than the oil obtained from Chemlali: the most abundant olive cultivar in Tunisia. Finally, the main fatty acids (palmitic (C16:0), oleic (C18:1) and linoleic (C18:2)) of nine of the studied virgin olive oils were compared to those sampled from their traditional areas. Except for Koroneiki and Olivière oils which showed an unchanged fatty acid composition and for Cornezuelo oil in which the level of oleic acid raised and the level of linoleic acid decreased, most of oils showed a decrease in oleic acid rates and an increase in palmitic and linoleic acid percentages as compared to those from their original sites.
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Fruits from the same cultivar of
Olea europaea
L. cv. Chaaibi were picked at the same ripeness stage and processed quickly across varied environmental conditions in Tunisia. Solid-phase ...micro-extraction (SPME) coupled with gas chromatography–mass spectrometry (GC–MS) were used to determine the aroma profile of virgin olive oils. The volatile profiling was mostly constituted of compounds from the following chemical classes: esters, aldehydes, alcohols, and hydrocarbons. Significant variances in the percentages of volatile constituents in oils from diverse geographical origins were discovered, with the aldehyde (E)-2-hexenal being the predominant volatile in almost half of the oil samples. The findings imply that, in addition to genetics, growing area impacts aroma composition. Remarkably, the proportions of volatile compounds and fatty acid compositions in oils collected from different growing areas exhibited strong variability. These findings can be utilized to distinguish and describe Chaaibi olive oils from various areas.
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CEKLJ, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
HPLC analysis with diode array and fluorescence detector, respectively was applied to the analysis of phenolic and tocopherol compounds of virgin olive oils from Chemlali variety cultivated in ...different altitude levels. Thus, olives of the same stages of maturation were harvested from four altitude levels in the Cap Bon Peninsula region of Tunisia for oil extraction and analysis. The results showed that the samples were of excellent quality and that there are significant differences in the level of bioactive compounds depending on the altitude level. A total of fifteen phenolic compounds were characterized for this purpose, which mainly belong to the chemical classes of secoiridoids, alcohols, esters, aldehydes, flavonoids, lignans and acids. Similarly, to the phenolic compounds, tocopherols strongly varied according to the altitude. The phenolic and tocopherol contents of extra virgin olive oils (EVOOs) originating from moderate (150 m–250 m) and high (> 400 m) altitude areas were higher (494 mg kg
−1
and 252.5 mg kg
−1
, respectively), than those from lower altitude (76.5 mg kg
−1
and 151.3 mg kg
−1
, respectively). The results suggest that, in addition to genetic factors, environmental conditions also influence the formation of bioactive substances.
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CEKLJ, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The effects of ripening degree of olives on volatile profile of monovarietal virgin olive oils (VOO) from Tunisian and Sicilian cultivars were investigated. Fruits obtained from Tunisia (Chétoui and ...Chemlali) and Italy (Nocellara del Belice, Biancolilla and Cerasuola) were picked at three different stages of ripeness and then immediately processed. Moreover, the changes in volatile composition were evaluated in Chétoui variety as a function of the irrigation regime versus the rain-fed control. Using headspace–solid-phase microextraction (HS–SPME) technique coupled to GC–MS and GC–FID, the volatile compounds of the monovarietal virgin olive oils were identified and quantitatively analyzed. The proportions of different classes of volatiles of oils showed significant differences throughout the maturity process. The results suggest that adding to the genetic factor; agronomic conditions affect the volatile formation and therefore the organoleptic properties of VOO.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
This study aims to investigate the influence of traditional maceration upon the enrichment of olive oil with oleaster leaves. The phenolic and tocopherolic compositions of control olive oil and ...enriched olive oils were determined. The influence of these oil preparation procedures on oil quality indicators was also investigated through spectrophotometric indices and fatty acid profiles. The total contents of bioactive compounds and pigments improved in oils obtained by maceration of fresh wild olive leaves, and were in statistically significant correlation with leaves proportions additions. The obtained results revealed that 15 phenolic compounds belonging to different phenolic types were characterized and quantified by an effective HPLC–DAD–ESI–MS/MS method. In all expected olive oils, the oleuropein aglycon (3,4-DHPEA-EA), and ligstroside aglycon (
p
-HPEAEA) derivatives were the most abundant compounds. Similarly, to phenolic compounds, tocopherols strongly increased with leaves addition during maceration process.
The data obtained from this study suggested that the addition of olive leaf to oils allowed more functional olive oils with higher antioxidant contents. Thus, Extra Virgin Olive Oil (EVOO) extracted with 10% of olive leaves presented the highest amount of phenolic and tocopherol compounds.
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CEKLJ, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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