Mohamed Bouaziz | Sfax University Tunisia (original) (raw)

Papers by Mohamed Bouaziz

Quality Assurance and Safety of Crops & Foods

The table olive industry produces a large amount of wastewater that can be expensive to be treate... more The table olive industry produces a large amount of wastewater that can be expensive to be treated and harmful to the environment. This study aimed to find a way to reuse brine water from the production of black and green table olive brines from Bejaia and Mascara of the Sigoise cultivar in order to create a valuable byproduct and con-tribute to sustainable development. In this context, the high-performance liquid chromatography–diode-array detection (HPLC-DAD) analysis revealed the highest concentration of hydroxytyrosol (4-(2-dihydroxy phenyl ethanol); 69.67 mg/100 mg) for green table olive brines of Mascara (EOGM) and tyrosol (Ty) (28.8 mg/100 mg) for black table olive brines of Bejaia (EOBB). Presence of polyphenols and ortho-diphenols could be responsible for their antioxidant, anti-inflammatory, and antibacterial properties. To assess antioxidant activity, the scavenging effects of DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,20-Azinobis[3-ethylbenzothiazoline-6-sulfonate]...

Food Analytical Methods

This research work was performed on olive orchards (Olea europaea L., cv. Chemlali) of different ... more This research work was performed on olive orchards (Olea europaea L., cv. Chemlali) of different origin areas of olive trees exposed to atmospheric contamination and those growing in a relatively clean area, during two successive years (2015/2016 and 2016/2017). Volatile profile of olive oil samples was carried out by headspace solid-phase micro-extraction coupled with gas chromatography/mass spectrometry (HS-SPME-GC/MS). A total of 93 volatile compounds, belonging to several classes of compounds, such as hydrocarbons, aldehydes, ketones, alcohols, terpenoids, and esters, were identified. Indeed, the analysis of phenols was performed by high-performance liquid chromatography with absorbance and fluorometric detection. Discriminant analysis confirmed that the pattern of volatile compounds includes enough information to predict sample variety amongst discrete monovarietal olive oil. The results indicate that climatic factors strongly effect volatile formation and phenolic composition and are supposed to be suitable markers of the geographic origin.

European Food Research and Technology

In this study, the effects of cultivar, harvest year and the geographical regions were investigat... more In this study, the effects of cultivar, harvest year and the geographical regions were investigated by determining the sensory and chemical characteristics (Fatty acids, Triacyglycerid and Tocopherols compositions) of the cultivars from different geographical origins (Tunisia, Portugal, France and Turkey) over a 2-year harvest period. Parameters such as palmitic acid, oleic acid, linoleic acid and oxidative stability were found to be significantly affected according to the region and cultivar. The highest linoleic and lowest oleic acid content were detected in Tunisia. The amount of palmitic acid was found to be higher in some cultivar (Tunisia and Turkey) than in others (Portugal and France). Nevertheless, principal component analysis allowed us to highlight the Tunisian olive oils for its interesting oxidative stability.

Journal of Food Measurement and Characterization, 2021

Several compositional parameters (fatty acids, tocopherols, polar phenols and volatiles) in virgi... more Several compositional parameters (fatty acids, tocopherols, polar phenols and volatiles) in virgin olive oils from varieties located at the center of Tunisia, namely Baldi, Chemchali, Neb Jmel, Tounsi and Besbessi from Gafsa and Chemchali and Sehli cultivated in Sidi Bouzid, were studied. To the best of our knowledge, this is the first study focusing on the chemical composition of virgin olive oils (VOO) from Sidi Bouzid. Significant differences were found between varieties from Sidi Bouzid and Gafsa in monounsaturated saturated fatty acid levels, some volatile compounds and γ-tocopherol amounts. Notably, Tounsi and Baldi VOOs showed the highest six carbon atoms alcohol contents, whereas Neb Jmel VOO revealed the highest aldehyde six carbon atoms content. Fatty acid composition, as well as tocopherol content, showed differences among different VOO. Principal component analysis and hierarchical component analysis on polar phenols, fatty acids, tocopherols and volatiles data evidenced...

Sustainability, 2022

The environmental impacts of irrigating an olive field with olive mill wastewater (OMW) and treat... more The environmental impacts of irrigating an olive field with olive mill wastewater (OMW) and treated wastewater (TWW) on soil properties were investigated. The effect of different irrigation treatments of OMW (50 m3 ha−1, 100 m3 ha−1, and 200 m3 ha−1) and TWW at different soil depths was studied. The obtained findings revealed that TWW application augmented soil pH; EC values; and P, K and Ca contents in all soil layers. However, Mg and Na concentrations, as well as organic matter content (OM), were proven to decrease with TWW irrigation throughout the experiment. Whereas soil adjusted with OMW showed a decrease in K, Ca, Mg and Na contents with soil depth, a significant increase was observed with the increase in applied OMW dose. On the other hand, total phenols and OM content increased significantly with the rise in OMW levels in all the investigated layers compared to the control sample.

Reaction Kinetics, Mechanisms and Catalysis, 2022

The present research work undertakes the investigation of an effective and inexpensive process to... more The present research work undertakes the investigation of an effective and inexpensive process to produce hydroxytyrosol, a naturally occurring orthodiphenolic antioxidant molecule found in olive oil from its monophenolic precursor tyrosol. This conversion was achieved from the wet hydrogen peroxide catalytic oxidation with montmorillonite KSF as economical and environment-friendly solid acid at room temperature. The impact of the primary functional parameters comprising tyrosol, H2O2, catalyst concentration and the interaction between them were performed using an experimental design Box-Behnken methodology. The percentage of 80% of tyrosol was converted, under the optimized operating conditions with higher hydroxytyrosol selectivity up to 90%. A kinetics of a pseudo first order pertaining to the tyrosol concentration was noticed. Montmorillonite KSF shows excellent stability and can be reused in three runs without significant activity decrease. The proposed procedure, investigated for the first time, is operationally simple and could find applications for industrial purposes.

Recent Advances in Environmental Science from the Euro-Mediterranean and Surrounding Regions (2nd Edition), 2021

European Food Research and Technology, 2021

Adulteration of olive oil during the packaging process may take place by accidental contamination... more Adulteration of olive oil during the packaging process may take place by accidental contamination. The development of analytical methodologies which enable detection of adulterations is warranted, since the addition of refined vegetable oils to refined olive oil (ROO) at low percentages could be a very challenging task. For this purpose, refined soybean, sunflower, corn and rapeseed oil are used for ROO fraudulent operation. ΔECN42 could be used as a parameter for the detection of ROO fraud with 0.5% refined corn oil (RCO), 0.5% refined soybean oil (RSbO), 0.4% refined rapeseed oil (RRO) and 0.1% refined sunflower oil (RSfO). The global method can be used as an effective parameter in refined olive oil adulteration even at low levels: 0.4% of RCO and RRO, 0.3% of RSbO and 0.1% of RSfO. The sterol composition can be considered as good markers of purity. Linear discriminant analysis could represent the most discriminant variable and fast tool for evaluation of ROO adulteration.

Food Analytical Methods, 2021

The undeclared blending of extra virgin olive oils (EVOOs) with refined pomace olive oils (RPOO) ... more The undeclared blending of extra virgin olive oils (EVOOs) with refined pomace olive oils (RPOO) is a well-known fraudulent practice. Despite the efforts made, it still remains a highly challenging authenticity issue to deal with. The present paper presents a fast fingerprint aroma technique, namely gas chromatography–olfactometry-mass spectrometry, which were tested as rapid screening tools for the detection of this adulteration.To overcome the lack of real adulterated samples was used to prepare EVOO mixtures with RPOO at different percentages. Besides, the quality indices was used as good markers to detect the illicit blends from the authentic oils such as K232 with 4% RPOO, K270 with 3% RPOO, and the variation of specific extinction (ΔK) of the adulterated EVOO with 10% RPOO. The addition of > 20% RPOO to EVOO would not be detected by the amount of TC18:1, fatty acids, and peroxide value. Moreover, using the sum of octadecadienoic and octadecatrienoic TFA isomers (TC18:2 + TC18:3) was confirmed to be good purity indices for the adulteration with 10 and 20% of RPOO. However, the main triglyceride found in oils samples were SOL + POO, OOL + LnPP, and OOO + PoPP as expected from the high oleic acid and low contents in linoleic and linoleic acid. Regarding volatile composition, thirty-four relevant aroma compounds and twenty-one key odorants were quantified in EVOO, RPOO, and EVOO adulterated with 1–20% of RPOO.

Journal of Agricultural and Food Chemistry, 2020

Since olive leaf is a potential source of phenolic fraction that is assumed to have good antioxid... more Since olive leaf is a potential source of phenolic fraction that is assumed to have good antioxidative effects, we purposed to add its extract to the refined olive-pomace oil during heating to increase its oxidative stability. RP-UHPLC-DAD-QTOF-MS was employed to characterize the phenolic fraction. The oil samples were evaluated by measuring the polymers and the polar compounds and thus detecting specific oxidized compounds. Using this approach, the results showed that incorporating olive leaf extract in refined oil significantly reduced the formation of polymers from 14.39% to 10.45% and the oxidation state by the variation of extinction K from 3.02 to 2.29 during 20 h of heating compared to unenriched oil. This study has proven that the use of natural substances is an opportunity to extend the life of refined oils.

European Food Research and Technology, 2020

The hand-held LC-DAD/ESI-MS/MS approach was employed, for the first time, for the quantification ... more The hand-held LC-DAD/ESI-MS/MS approach was employed, for the first time, for the quantification of extra virgin olive oil (EVOO) adulteration with refined pomace olive oil (RPOO). The total polyphenols (TP) and sterols were quantified according to their chemical methods, with more reliable methods required in this field to avoid undue dependence on chlorophylls, carotenoids contents and antioxidant activity (DPPH assays), which were evaluated by spectrophotometric methods. Some differences concerning the antioxidant activity and the TP content were observed. Actually, Chemlali EVOO activity was the most pronounced (13.84 ± 0.21%) and it contained the highest TP content (284.54 ± 4.27 mg/kg). Indeed, a correlation between antioxidant activity, TP and oxidative stability was established herewith. The metabolomics data were elaborated with the help of chemometric tools i.e. principal component analysis (PCA) and hierarchical cluster analysis (HCA). This approach allowed the estimation of the best discrimination markers for EVOO authenticity evaluation (i.e. Hydroxytyrosol quinone, oxidized hydroxytyrosol, 3,4-DHPEA-EA, p-HPEA (tyrosol), p-coumaric acid, luteolin, decarboxymethyl 10-hydroxyoleuropein aglycon, β-sitosterol apparently; campesterol, stigmasterol, ∆-7-stigmastenol and ∆-7-avenasterol).

International Journal of Chemical Kinetics, 2019

An effective procedure was developed to produce high-value added phenolic compounds through the c... more An effective procedure was developed to produce high-value added phenolic compounds through the conversion of 2-phenylethanol (2-PhEt) by using acid-activated clays KSF for the hydrogen peroxide. Owing to KSF's ability to catalyze a variety of complex oxidations, it was likely to convert 2-PhEt to hydroxytyrosol (HTY) and tyrosol (TY) derivatives. The analyses of catalytic solution revealed that the optimum conditions, giving a higher concentration of oxidation products such as HTY, were as follows: 2-PhEt concentration 10 −2 mol/L, the hydrogen peroxide concentration 5.05 × 10 −2 and 0.6 g L-1 of KSF clays. The yield during the conversion reaction into HTY was around 25%. All compounds in the reaction mixture were identified by mass spectrophotometry using a LC-MS apparatus. HTY, TY, meta-tyrosol and ortho-tyrosol were the major compounds. The antioxidant activity was realized by 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. In fact, it is revealed that the strongest inhibition percentage (PI = 96) was detected with the increase in the concentration of HTY. The approach proposed in the present work presents an environment friendly method.

European Food Research and Technology, 2018

The aim of this study is to evaluate the formation of the increase of Δ-7-stigmastenol during the... more The aim of this study is to evaluate the formation of the increase of Δ-7-stigmastenol during the chemical refining of pomace olive oil (POO) and the optimal neutralization by NaOH concentration of 20 °Be at a temperature of 70 °C. A comparison has been made between virgin olive oil (VOO) and consecutive steps of refining process in the amounts of Δ-7-stigmastenol of the POO oil samples. Among the oils, refined olive oil particularly the neutralized olive oil (NOO) by soda (NaOH) contained a high-level of Δ-7-stigmastenol. A mean result found in NOO by different concentration of NaOH from 15 to 25 °Be showed increased values significantly (p < 0.05) from 0.70 ± 0.01% to 0.78 ± 0.01% of Δ-7-stigmastenol and increased significantly (p < 0.05) the levels of erythrodiol and uvaol from 26.34 ± 0.39% to 28.11 ± 0.42%. Then, the concentration of the ∆-7-stigmastenol was evaluated using a GC-MS instrument. Besides, further analyses were performed to ensure the uniqueness of the peak of Δ-7-stigmastenol and absence of any overlap. In all cases, the level of Δ-7-stigmastenol was higher than the limit set by the International Olive Council.

Reaction Kinetics, Mechanisms and Catalysis, 2019

A successful procedure to demonstrate the ability to produce high-added value phenolic hydroxytyr... more A successful procedure to demonstrate the ability to produce high-added value phenolic hydroxytyrosol by oxidation of m-tyrosol was developed, using clay KSF/H 2 O with peroxide hydrogen to afford excellent yields (more than 60%). Three different operating parameters, including m-tyrosol, H 2 O 2 concentration and amount of catalyst were performed using an experimental design methodology "Box-Behnken" for hydroxytyrosol production. All derivative compounds in reaction mixture during reaction time were identified using mass spectrometry. Hydroxytyrosol 3,4-dihydroxystyrene; 3-hydroxyphenyl acetic acid and 2.5-dihydroxyphenylethanol were the major compounds. By means of 2,2-diphenyl-1-picrylhydrazyl DPPH method, the antioxidant activity was realized, indicating that the strongest antiradical activity (IC 50% = 21.57 mg/mL) was detected when the concentration of hydroxytyrosol is higher. The developed synthesis, investigated for the first time, is operationally simple and could find application for industrial purposes. Keywords m-Tyrosol • Oxidation • H 2 O 2 • KSF clay • Response surface methodology Abbreviations m-Tyr Méta-tyrosol HT Hydroxytyrosol LC-MS/MS Liquid chromatography coupled to mass spectrometry Electronic supplementary material The online version of this article (

European Journal of Lipid Science and Technology, 2019

Given the importance of olive oil as a food product worldwide and given the exposure of many prod... more Given the importance of olive oil as a food product worldwide and given the exposure of many productive olive orchards to many pollution sources, this work is a contribution to the clarification of atmospheric metal pollution effects on the quality of olive oil and its possible toxicity for human beings. This work is carried out on olive orchards (Olea europaea L., cv. Chemlali) situated in a polluted region close to a fertilizer factory and in a controlled, unpolluted area, managed with comparable cultivation techniques during two successive years (2015/2016 and 2016/2017). Pollution negatively affects the oxidative stability and nutritional value of olive oil, especially by decreasing the contents of antioxidant compounds and the fatty acid composition. Atmospheric metals are confirmed to have a negative effect on olive oil chemicals; oils show a disruption of their squalene, tocopherols, and triglyceride composition in comparison with control oils. Practical Applications: This study is carried out in two olive orchards (Olea europaea L., cv. Chemlali) located in a polluted area near a fertilizer factory and in a control unpolluted site, managed with similar cultivation techniques. The aim is to investigate the physiological and biochemical responses of polluted oils (PO), exposed to atmospheric metal contamination as compared to control oils (CO). The results of this study emanate from the accidental exposure to contamination sources, such as the direct contact of olives, with an elevated polluted environment that might be made more severe by gaseous air pollutants emitted by the factory. Then, air contamination avoidance from factories should be examined together with any possible probable methodologies to decrease plant tissue contamination.

Sustainability, 2019

Waste oils are becoming increasingly more important as feedstock for the production of fuels and ... more Waste oils are becoming increasingly more important as feedstock for the production of fuels and glycerol as byproduc. Optimization of homogeneous transesterification of waste frying oil (WFO) to biodiesel over hydroxide potassium (KOH) catalyst have been investigated. In this respect, response surface methodology (RSM) was applied to determine the relationships between methanol and WFO molar ratio (3:1–12:1), KOH concentration (0.5%–2%) and temperature (25–65 °C) on the conversion yield. Transesterification of WFO produced 96.33% maximum methyl ester yield at the optimum methanol/WFO molar ratio 7.3:1, KOH loading 0.5 wt. % and the reaction temperature was 58.30 °C. The physicochemical properties of optimized biodiesel met the requirements of the European Norm 14214, such as kinematic viscosity at 40 °C 4.57 mm/s2, the sulfur content 0.005 wt. %, and the density at 15 °C 889.3 kg/m3. This study also examined the accelerated oxidation of biodiesel and biodiesel/diesel blends under c...

European Food Research and Technology, 2019

The present study reports the olive oil quality properties, namely free fatty acid, peroxides ind... more The present study reports the olive oil quality properties, namely free fatty acid, peroxides index, purity properties [fatty acid and triacylglycerol (TAG) composition], antioxidant compounds (total phenol, carotenoid and chlorophyll content) and oxidative stability. These analyses were performed for three rare cultivars grown in southern Tunisia (region of Tataouine). All the samples have presented good quality according to the international olive council norms. Nevertheless, there was a difference in many of the evaluated parameters as a function of ripening stages and cultivars. The oleic acid and linoleic acid amounts of olive oils increased with the ripening progress, with the highest rates were found in Fakhari cultivar. The most abundant triacylglycerols of olive oils were OOO, POO, LOO + PLnP, PLO + SLL and POP. Moreover, a general decrease (p < 0.05) of the total phenolic content, pigments content and oxidative stability were observed during maturation. The principal component analysis was used to classify nine olive oils samples depending on cultivars and maturity degree.

Nowadays, the fingerprinting methodologies of olive oils are dominated. They consider the entire ... more Nowadays, the fingerprinting methodologies of olive oils are dominated. They consider the entire analytical signal, which is acquired and recorded by the analytical instrument, directly from olive oil or isoleted fraction, i,e chromatogram. The shape and intensity of the recorded signal the instrumental fingerprint from the whole olive oil adulteration. Therefore, the methodolygy is based on the chemical composition (Fatty acids and Triglycerides compositions). However, Fatty acids composition as an indicator of purity suggests that linolenic acid content could be used as a parameter for the detection of extra virgin olive oil fraud with 5% of soybean oil. The adulteration could also be detected by the increase of the trans-fatty acid contents with 3% of soybean oil, 2% of corn oil and 4% of sunflower oil. The use of the ∆ECN42 proved to be effective in the Chemlali extra-virgin olive oil adulteration even at low levels: 1% of sunflower oil, 3% of soybean oil and 3% of corn oil. The...

Food Chemistry, 2018

Micromeria fruticosa is an important crop, is widely used in the Mediterranean basin as food and ... more Micromeria fruticosa is an important crop, is widely used in the Mediterranean basin as food and in folk medicine, owing to its health-promoting properties, partially due to the secondary metabolite composition. However, complete information on the phyto-metabolites in M. fruticosa is still lacking. Plant leaves were extracted in methanol (80%), then the phyto-metabolites were separated on C18 column and an extensive characterization using UHPLC-DAD-ESI-QTOF-MS 2 method in two ionization modes was established. A total of 215 phenolics and other compounds were tentatively identified, offering the first comprehensive study available on the phytochemicals from M. fruticosa. Over 180 phytochemicals (87 flavonoids, 41 phenolic acids, 16 terpenoids, 8 sulfate derivatives, 7 iridoids, and others) are reported in Micromeria for the first time. M. fruticosa can be a promising source of functional ingredients and has use in the food, pharma and nutraceutical industries.

European Food Research and Technology, 2018

The aim of this work was to compare the frying stability of refined olive pomace oil alone and bl... more The aim of this work was to compare the frying stability of refined olive pomace oil alone and blended with refined coconut oil during 60 successive sessions. Frying experiments were carried out at 180 °C and samples were evaluated by high-performance size-exclusion chromatography (HPSEC), measuring the polymers and polar compounds formed. The tocopherol content was also analyzed. At the end of the frying process, the lowest content of polymeric compounds (PC) and total polar compounds (TPC) were detected for the blend of refined olive pomace oil-refined coconut oil (ROPO/RCO) with 13.20% and 25%, respectively, compared to refined olive pomace oil (ROPO) pure with 16.9% and 34.5%, respectively. Hence, the present study based on PC and TPC as best quality indicators of frying oil degradation indicated that the frying behavior of ROPO pure significantly improved by the blending application with RCO and showed a higher chemical stability.

Quality Assurance and Safety of Crops & Foods

The table olive industry produces a large amount of wastewater that can be expensive to be treate... more The table olive industry produces a large amount of wastewater that can be expensive to be treated and harmful to the environment. This study aimed to find a way to reuse brine water from the production of black and green table olive brines from Bejaia and Mascara of the Sigoise cultivar in order to create a valuable byproduct and con-tribute to sustainable development. In this context, the high-performance liquid chromatography–diode-array detection (HPLC-DAD) analysis revealed the highest concentration of hydroxytyrosol (4-(2-dihydroxy phenyl ethanol); 69.67 mg/100 mg) for green table olive brines of Mascara (EOGM) and tyrosol (Ty) (28.8 mg/100 mg) for black table olive brines of Bejaia (EOBB). Presence of polyphenols and ortho-diphenols could be responsible for their antioxidant, anti-inflammatory, and antibacterial properties. To assess antioxidant activity, the scavenging effects of DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,20-Azinobis[3-ethylbenzothiazoline-6-sulfonate]...

Food Analytical Methods

This research work was performed on olive orchards (Olea europaea L., cv. Chemlali) of different ... more This research work was performed on olive orchards (Olea europaea L., cv. Chemlali) of different origin areas of olive trees exposed to atmospheric contamination and those growing in a relatively clean area, during two successive years (2015/2016 and 2016/2017). Volatile profile of olive oil samples was carried out by headspace solid-phase micro-extraction coupled with gas chromatography/mass spectrometry (HS-SPME-GC/MS). A total of 93 volatile compounds, belonging to several classes of compounds, such as hydrocarbons, aldehydes, ketones, alcohols, terpenoids, and esters, were identified. Indeed, the analysis of phenols was performed by high-performance liquid chromatography with absorbance and fluorometric detection. Discriminant analysis confirmed that the pattern of volatile compounds includes enough information to predict sample variety amongst discrete monovarietal olive oil. The results indicate that climatic factors strongly effect volatile formation and phenolic composition and are supposed to be suitable markers of the geographic origin.

European Food Research and Technology

In this study, the effects of cultivar, harvest year and the geographical regions were investigat... more In this study, the effects of cultivar, harvest year and the geographical regions were investigated by determining the sensory and chemical characteristics (Fatty acids, Triacyglycerid and Tocopherols compositions) of the cultivars from different geographical origins (Tunisia, Portugal, France and Turkey) over a 2-year harvest period. Parameters such as palmitic acid, oleic acid, linoleic acid and oxidative stability were found to be significantly affected according to the region and cultivar. The highest linoleic and lowest oleic acid content were detected in Tunisia. The amount of palmitic acid was found to be higher in some cultivar (Tunisia and Turkey) than in others (Portugal and France). Nevertheless, principal component analysis allowed us to highlight the Tunisian olive oils for its interesting oxidative stability.

Journal of Food Measurement and Characterization, 2021

Several compositional parameters (fatty acids, tocopherols, polar phenols and volatiles) in virgi... more Several compositional parameters (fatty acids, tocopherols, polar phenols and volatiles) in virgin olive oils from varieties located at the center of Tunisia, namely Baldi, Chemchali, Neb Jmel, Tounsi and Besbessi from Gafsa and Chemchali and Sehli cultivated in Sidi Bouzid, were studied. To the best of our knowledge, this is the first study focusing on the chemical composition of virgin olive oils (VOO) from Sidi Bouzid. Significant differences were found between varieties from Sidi Bouzid and Gafsa in monounsaturated saturated fatty acid levels, some volatile compounds and γ-tocopherol amounts. Notably, Tounsi and Baldi VOOs showed the highest six carbon atoms alcohol contents, whereas Neb Jmel VOO revealed the highest aldehyde six carbon atoms content. Fatty acid composition, as well as tocopherol content, showed differences among different VOO. Principal component analysis and hierarchical component analysis on polar phenols, fatty acids, tocopherols and volatiles data evidenced...

Sustainability, 2022

The environmental impacts of irrigating an olive field with olive mill wastewater (OMW) and treat... more The environmental impacts of irrigating an olive field with olive mill wastewater (OMW) and treated wastewater (TWW) on soil properties were investigated. The effect of different irrigation treatments of OMW (50 m3 ha−1, 100 m3 ha−1, and 200 m3 ha−1) and TWW at different soil depths was studied. The obtained findings revealed that TWW application augmented soil pH; EC values; and P, K and Ca contents in all soil layers. However, Mg and Na concentrations, as well as organic matter content (OM), were proven to decrease with TWW irrigation throughout the experiment. Whereas soil adjusted with OMW showed a decrease in K, Ca, Mg and Na contents with soil depth, a significant increase was observed with the increase in applied OMW dose. On the other hand, total phenols and OM content increased significantly with the rise in OMW levels in all the investigated layers compared to the control sample.

Reaction Kinetics, Mechanisms and Catalysis, 2022

The present research work undertakes the investigation of an effective and inexpensive process to... more The present research work undertakes the investigation of an effective and inexpensive process to produce hydroxytyrosol, a naturally occurring orthodiphenolic antioxidant molecule found in olive oil from its monophenolic precursor tyrosol. This conversion was achieved from the wet hydrogen peroxide catalytic oxidation with montmorillonite KSF as economical and environment-friendly solid acid at room temperature. The impact of the primary functional parameters comprising tyrosol, H2O2, catalyst concentration and the interaction between them were performed using an experimental design Box-Behnken methodology. The percentage of 80% of tyrosol was converted, under the optimized operating conditions with higher hydroxytyrosol selectivity up to 90%. A kinetics of a pseudo first order pertaining to the tyrosol concentration was noticed. Montmorillonite KSF shows excellent stability and can be reused in three runs without significant activity decrease. The proposed procedure, investigated for the first time, is operationally simple and could find applications for industrial purposes.

Recent Advances in Environmental Science from the Euro-Mediterranean and Surrounding Regions (2nd Edition), 2021

European Food Research and Technology, 2021

Adulteration of olive oil during the packaging process may take place by accidental contamination... more Adulteration of olive oil during the packaging process may take place by accidental contamination. The development of analytical methodologies which enable detection of adulterations is warranted, since the addition of refined vegetable oils to refined olive oil (ROO) at low percentages could be a very challenging task. For this purpose, refined soybean, sunflower, corn and rapeseed oil are used for ROO fraudulent operation. ΔECN42 could be used as a parameter for the detection of ROO fraud with 0.5% refined corn oil (RCO), 0.5% refined soybean oil (RSbO), 0.4% refined rapeseed oil (RRO) and 0.1% refined sunflower oil (RSfO). The global method can be used as an effective parameter in refined olive oil adulteration even at low levels: 0.4% of RCO and RRO, 0.3% of RSbO and 0.1% of RSfO. The sterol composition can be considered as good markers of purity. Linear discriminant analysis could represent the most discriminant variable and fast tool for evaluation of ROO adulteration.

Food Analytical Methods, 2021

The undeclared blending of extra virgin olive oils (EVOOs) with refined pomace olive oils (RPOO) ... more The undeclared blending of extra virgin olive oils (EVOOs) with refined pomace olive oils (RPOO) is a well-known fraudulent practice. Despite the efforts made, it still remains a highly challenging authenticity issue to deal with. The present paper presents a fast fingerprint aroma technique, namely gas chromatography–olfactometry-mass spectrometry, which were tested as rapid screening tools for the detection of this adulteration.To overcome the lack of real adulterated samples was used to prepare EVOO mixtures with RPOO at different percentages. Besides, the quality indices was used as good markers to detect the illicit blends from the authentic oils such as K232 with 4% RPOO, K270 with 3% RPOO, and the variation of specific extinction (ΔK) of the adulterated EVOO with 10% RPOO. The addition of > 20% RPOO to EVOO would not be detected by the amount of TC18:1, fatty acids, and peroxide value. Moreover, using the sum of octadecadienoic and octadecatrienoic TFA isomers (TC18:2 + TC18:3) was confirmed to be good purity indices for the adulteration with 10 and 20% of RPOO. However, the main triglyceride found in oils samples were SOL + POO, OOL + LnPP, and OOO + PoPP as expected from the high oleic acid and low contents in linoleic and linoleic acid. Regarding volatile composition, thirty-four relevant aroma compounds and twenty-one key odorants were quantified in EVOO, RPOO, and EVOO adulterated with 1–20% of RPOO.

Journal of Agricultural and Food Chemistry, 2020

Since olive leaf is a potential source of phenolic fraction that is assumed to have good antioxid... more Since olive leaf is a potential source of phenolic fraction that is assumed to have good antioxidative effects, we purposed to add its extract to the refined olive-pomace oil during heating to increase its oxidative stability. RP-UHPLC-DAD-QTOF-MS was employed to characterize the phenolic fraction. The oil samples were evaluated by measuring the polymers and the polar compounds and thus detecting specific oxidized compounds. Using this approach, the results showed that incorporating olive leaf extract in refined oil significantly reduced the formation of polymers from 14.39% to 10.45% and the oxidation state by the variation of extinction K from 3.02 to 2.29 during 20 h of heating compared to unenriched oil. This study has proven that the use of natural substances is an opportunity to extend the life of refined oils.

European Food Research and Technology, 2020

The hand-held LC-DAD/ESI-MS/MS approach was employed, for the first time, for the quantification ... more The hand-held LC-DAD/ESI-MS/MS approach was employed, for the first time, for the quantification of extra virgin olive oil (EVOO) adulteration with refined pomace olive oil (RPOO). The total polyphenols (TP) and sterols were quantified according to their chemical methods, with more reliable methods required in this field to avoid undue dependence on chlorophylls, carotenoids contents and antioxidant activity (DPPH assays), which were evaluated by spectrophotometric methods. Some differences concerning the antioxidant activity and the TP content were observed. Actually, Chemlali EVOO activity was the most pronounced (13.84 ± 0.21%) and it contained the highest TP content (284.54 ± 4.27 mg/kg). Indeed, a correlation between antioxidant activity, TP and oxidative stability was established herewith. The metabolomics data were elaborated with the help of chemometric tools i.e. principal component analysis (PCA) and hierarchical cluster analysis (HCA). This approach allowed the estimation of the best discrimination markers for EVOO authenticity evaluation (i.e. Hydroxytyrosol quinone, oxidized hydroxytyrosol, 3,4-DHPEA-EA, p-HPEA (tyrosol), p-coumaric acid, luteolin, decarboxymethyl 10-hydroxyoleuropein aglycon, β-sitosterol apparently; campesterol, stigmasterol, ∆-7-stigmastenol and ∆-7-avenasterol).

International Journal of Chemical Kinetics, 2019

An effective procedure was developed to produce high-value added phenolic compounds through the c... more An effective procedure was developed to produce high-value added phenolic compounds through the conversion of 2-phenylethanol (2-PhEt) by using acid-activated clays KSF for the hydrogen peroxide. Owing to KSF's ability to catalyze a variety of complex oxidations, it was likely to convert 2-PhEt to hydroxytyrosol (HTY) and tyrosol (TY) derivatives. The analyses of catalytic solution revealed that the optimum conditions, giving a higher concentration of oxidation products such as HTY, were as follows: 2-PhEt concentration 10 −2 mol/L, the hydrogen peroxide concentration 5.05 × 10 −2 and 0.6 g L-1 of KSF clays. The yield during the conversion reaction into HTY was around 25%. All compounds in the reaction mixture were identified by mass spectrophotometry using a LC-MS apparatus. HTY, TY, meta-tyrosol and ortho-tyrosol were the major compounds. The antioxidant activity was realized by 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. In fact, it is revealed that the strongest inhibition percentage (PI = 96) was detected with the increase in the concentration of HTY. The approach proposed in the present work presents an environment friendly method.

European Food Research and Technology, 2018

The aim of this study is to evaluate the formation of the increase of Δ-7-stigmastenol during the... more The aim of this study is to evaluate the formation of the increase of Δ-7-stigmastenol during the chemical refining of pomace olive oil (POO) and the optimal neutralization by NaOH concentration of 20 °Be at a temperature of 70 °C. A comparison has been made between virgin olive oil (VOO) and consecutive steps of refining process in the amounts of Δ-7-stigmastenol of the POO oil samples. Among the oils, refined olive oil particularly the neutralized olive oil (NOO) by soda (NaOH) contained a high-level of Δ-7-stigmastenol. A mean result found in NOO by different concentration of NaOH from 15 to 25 °Be showed increased values significantly (p < 0.05) from 0.70 ± 0.01% to 0.78 ± 0.01% of Δ-7-stigmastenol and increased significantly (p < 0.05) the levels of erythrodiol and uvaol from 26.34 ± 0.39% to 28.11 ± 0.42%. Then, the concentration of the ∆-7-stigmastenol was evaluated using a GC-MS instrument. Besides, further analyses were performed to ensure the uniqueness of the peak of Δ-7-stigmastenol and absence of any overlap. In all cases, the level of Δ-7-stigmastenol was higher than the limit set by the International Olive Council.

Reaction Kinetics, Mechanisms and Catalysis, 2019

A successful procedure to demonstrate the ability to produce high-added value phenolic hydroxytyr... more A successful procedure to demonstrate the ability to produce high-added value phenolic hydroxytyrosol by oxidation of m-tyrosol was developed, using clay KSF/H 2 O with peroxide hydrogen to afford excellent yields (more than 60%). Three different operating parameters, including m-tyrosol, H 2 O 2 concentration and amount of catalyst were performed using an experimental design methodology "Box-Behnken" for hydroxytyrosol production. All derivative compounds in reaction mixture during reaction time were identified using mass spectrometry. Hydroxytyrosol 3,4-dihydroxystyrene; 3-hydroxyphenyl acetic acid and 2.5-dihydroxyphenylethanol were the major compounds. By means of 2,2-diphenyl-1-picrylhydrazyl DPPH method, the antioxidant activity was realized, indicating that the strongest antiradical activity (IC 50% = 21.57 mg/mL) was detected when the concentration of hydroxytyrosol is higher. The developed synthesis, investigated for the first time, is operationally simple and could find application for industrial purposes. Keywords m-Tyrosol • Oxidation • H 2 O 2 • KSF clay • Response surface methodology Abbreviations m-Tyr Méta-tyrosol HT Hydroxytyrosol LC-MS/MS Liquid chromatography coupled to mass spectrometry Electronic supplementary material The online version of this article (

European Journal of Lipid Science and Technology, 2019

Given the importance of olive oil as a food product worldwide and given the exposure of many prod... more Given the importance of olive oil as a food product worldwide and given the exposure of many productive olive orchards to many pollution sources, this work is a contribution to the clarification of atmospheric metal pollution effects on the quality of olive oil and its possible toxicity for human beings. This work is carried out on olive orchards (Olea europaea L., cv. Chemlali) situated in a polluted region close to a fertilizer factory and in a controlled, unpolluted area, managed with comparable cultivation techniques during two successive years (2015/2016 and 2016/2017). Pollution negatively affects the oxidative stability and nutritional value of olive oil, especially by decreasing the contents of antioxidant compounds and the fatty acid composition. Atmospheric metals are confirmed to have a negative effect on olive oil chemicals; oils show a disruption of their squalene, tocopherols, and triglyceride composition in comparison with control oils. Practical Applications: This study is carried out in two olive orchards (Olea europaea L., cv. Chemlali) located in a polluted area near a fertilizer factory and in a control unpolluted site, managed with similar cultivation techniques. The aim is to investigate the physiological and biochemical responses of polluted oils (PO), exposed to atmospheric metal contamination as compared to control oils (CO). The results of this study emanate from the accidental exposure to contamination sources, such as the direct contact of olives, with an elevated polluted environment that might be made more severe by gaseous air pollutants emitted by the factory. Then, air contamination avoidance from factories should be examined together with any possible probable methodologies to decrease plant tissue contamination.

Sustainability, 2019

Waste oils are becoming increasingly more important as feedstock for the production of fuels and ... more Waste oils are becoming increasingly more important as feedstock for the production of fuels and glycerol as byproduc. Optimization of homogeneous transesterification of waste frying oil (WFO) to biodiesel over hydroxide potassium (KOH) catalyst have been investigated. In this respect, response surface methodology (RSM) was applied to determine the relationships between methanol and WFO molar ratio (3:1–12:1), KOH concentration (0.5%–2%) and temperature (25–65 °C) on the conversion yield. Transesterification of WFO produced 96.33% maximum methyl ester yield at the optimum methanol/WFO molar ratio 7.3:1, KOH loading 0.5 wt. % and the reaction temperature was 58.30 °C. The physicochemical properties of optimized biodiesel met the requirements of the European Norm 14214, such as kinematic viscosity at 40 °C 4.57 mm/s2, the sulfur content 0.005 wt. %, and the density at 15 °C 889.3 kg/m3. This study also examined the accelerated oxidation of biodiesel and biodiesel/diesel blends under c...

European Food Research and Technology, 2019

The present study reports the olive oil quality properties, namely free fatty acid, peroxides ind... more The present study reports the olive oil quality properties, namely free fatty acid, peroxides index, purity properties [fatty acid and triacylglycerol (TAG) composition], antioxidant compounds (total phenol, carotenoid and chlorophyll content) and oxidative stability. These analyses were performed for three rare cultivars grown in southern Tunisia (region of Tataouine). All the samples have presented good quality according to the international olive council norms. Nevertheless, there was a difference in many of the evaluated parameters as a function of ripening stages and cultivars. The oleic acid and linoleic acid amounts of olive oils increased with the ripening progress, with the highest rates were found in Fakhari cultivar. The most abundant triacylglycerols of olive oils were OOO, POO, LOO + PLnP, PLO + SLL and POP. Moreover, a general decrease (p < 0.05) of the total phenolic content, pigments content and oxidative stability were observed during maturation. The principal component analysis was used to classify nine olive oils samples depending on cultivars and maturity degree.

Nowadays, the fingerprinting methodologies of olive oils are dominated. They consider the entire ... more Nowadays, the fingerprinting methodologies of olive oils are dominated. They consider the entire analytical signal, which is acquired and recorded by the analytical instrument, directly from olive oil or isoleted fraction, i,e chromatogram. The shape and intensity of the recorded signal the instrumental fingerprint from the whole olive oil adulteration. Therefore, the methodolygy is based on the chemical composition (Fatty acids and Triglycerides compositions). However, Fatty acids composition as an indicator of purity suggests that linolenic acid content could be used as a parameter for the detection of extra virgin olive oil fraud with 5% of soybean oil. The adulteration could also be detected by the increase of the trans-fatty acid contents with 3% of soybean oil, 2% of corn oil and 4% of sunflower oil. The use of the ∆ECN42 proved to be effective in the Chemlali extra-virgin olive oil adulteration even at low levels: 1% of sunflower oil, 3% of soybean oil and 3% of corn oil. The...

Food Chemistry, 2018

Micromeria fruticosa is an important crop, is widely used in the Mediterranean basin as food and ... more Micromeria fruticosa is an important crop, is widely used in the Mediterranean basin as food and in folk medicine, owing to its health-promoting properties, partially due to the secondary metabolite composition. However, complete information on the phyto-metabolites in M. fruticosa is still lacking. Plant leaves were extracted in methanol (80%), then the phyto-metabolites were separated on C18 column and an extensive characterization using UHPLC-DAD-ESI-QTOF-MS 2 method in two ionization modes was established. A total of 215 phenolics and other compounds were tentatively identified, offering the first comprehensive study available on the phytochemicals from M. fruticosa. Over 180 phytochemicals (87 flavonoids, 41 phenolic acids, 16 terpenoids, 8 sulfate derivatives, 7 iridoids, and others) are reported in Micromeria for the first time. M. fruticosa can be a promising source of functional ingredients and has use in the food, pharma and nutraceutical industries.

European Food Research and Technology, 2018

The aim of this work was to compare the frying stability of refined olive pomace oil alone and bl... more The aim of this work was to compare the frying stability of refined olive pomace oil alone and blended with refined coconut oil during 60 successive sessions. Frying experiments were carried out at 180 °C and samples were evaluated by high-performance size-exclusion chromatography (HPSEC), measuring the polymers and polar compounds formed. The tocopherol content was also analyzed. At the end of the frying process, the lowest content of polymeric compounds (PC) and total polar compounds (TPC) were detected for the blend of refined olive pomace oil-refined coconut oil (ROPO/RCO) with 13.20% and 25%, respectively, compared to refined olive pomace oil (ROPO) pure with 16.9% and 34.5%, respectively. Hence, the present study based on PC and TPC as best quality indicators of frying oil degradation indicated that the frying behavior of ROPO pure significantly improved by the blending application with RCO and showed a higher chemical stability.