Percorrer por autor "Elamine, Youssef"
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- Antibacterial activity of moroccan zantaz honey and the influence of its physicochemical parameters using chemometric toolsPublication . Elamine, Youssef; Imtara, Hamada; Miguel, Maria da Graça; Anjos, Ofélia; Estevinho, Leticia M.; Alaiz, Manuel; Girón-Calle, Julio; Vioque, Javier; Martín, Jesús; Lyoussi, BadiâaThe emergence of multidrug-resistant bacteria has prompted the development of alternative therapies, including the use of natural products with antibacterial properties. The antibacterial properties of Zantaz honey produced in the Moroccan Atlas Mountains against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus was evaluated and analyzed using chemometric tools. Minimum inhibitory concentration (MIC) and Minimum bactericidal concentration (MBC) against S. aureus were the lowest (112.5 ± 54.5 mg/mL), revealing that this species was most sensitive to Zantaz honey. P. aeruginosa showed an intermediate sensitivity (MIC= 118.75 ± 51.9 mg/mL), while E. coli was the most resistant to treatment (MIC = 175 ± 61.2 mg/mL). Content of monosaccharides, certain minerals, and phenolic compounds correlated with antibacterial activity (p lt 0.05). Principal component analysis of physicochemical characteristics and antibacterial activity indicated that the parameters most associated with antibacterial activity were color, acidity, and content of melanoidins, fructose, epicatechin, methyl syringate, 4-coumaric acid, and 3-coumaric acid.
- Effect of extreme heat processing on the Moroccan Zantaz’ honey antioxidant activitiesPublication . Elamine, Youssef; Anjos, Ofélia; Estevinho, Leticia M.; Lyoussi, Badiâa; Aazza, Smail; Miguel, Maria da GraçaThe effect of an extreme heat processing on Zantaz honey samples was studied using a panel of physicochemical parameters, antioxidant activities and FTIR-ATR spectroscopy. Honey samples were heated at 121 C for 30 min and the heat processing effect was confirmed indirectly through the assessment of hydroxymethylfurfural content, for which the values increased significantly (p\0.01), and diastase activity, which was totally absent after the thermal processing. Besides, the effects of the heat on the antioxidant activities were diverse. Indeed, while the ability to scavenge 2,20-azinobis( 3-ethylbenzothiazoline-6-sulphonic acid cation radicals (ABTS ?) and 2,2-diphenyl-1-picrylhydrazyl radicals was enhanced (p\0.05 only for ABTS ?), after the heat processing, nitric oxide radicals scavenging activity was reduced drastically (p\0.01). Regarding the chelating power, it was totally abolished following heating. Other activities showed no significant alteration. The initial values of antioxidant activities seem to be determinant in the changes occurring after the heat processing. Amongst the analysed parameters, following the heat processing, the honey colour was the variable where the influence of baseline values was the greatest. The spectral analyses confirmed that FTIR-ATR is a useful technique to discriminate the chemical differences occurring in honey after heat processing.
- Electrical impedance spectroscopy for potassium content analysis and botanical origin identification of honeyPublication . Elamine, Youssef; Inácio, Pedro M.C.; Miguel, Maria da Graça; Carlier, Jorge D.; Costa, Maria Clara; Estevinho, Leticia M.; Gomes, Henrique L.Minerals are reported to dominate the electrical properties of honey and indicate its botanical and geographical origins. In this study, Electrochemical Impedance Spectroscopy (EIS) was used to assess the relation between mineral elements, electrical properties and botanical origin using three honey varieties - Citrus sp., Eucalyptus sp., and Erica sp. These varieties are identified through pollen analysis and market labelling. Flame atomic absorption and emission spectroscopies were used to quantify the concentrations of eight elements (potassium, sodium, calcium, magnesium, manganese, zinc, copper, and iron). Among all the mineral elements, potassium showed a consistent correlation with impedance. The potassium estimation in honey and standard solutions (calibration curve) had similar sensitivities of 153.43 nF/mM and 132.68 nF/mM, respectively. Additionally, the analysis revealed that potassium dominates the mineral composition, with the other species present in minimal quantities. The EIS technique showed high sensitivity to potassium and other ionisable species, making it possible to classify the botanical origin of these three honey types. The EIS technique proved to be both time and cost effective, yielding a classification rate higher than that achieved by analysing mineral composition.
- Insight into the sensing mechanism of an impedance based electronic tongue for honey botanic origin discriminationPublication . Elamine, Youssef; Inácio, Pedro M.C.; Lyoussi, Badiâa; Anjos, Ofélia; Estevinho, Leticia M.; Miguel, Maria da Graça; Gomes, Henrique L.Animpedance based electronictongue was developed and used to discriminate honey of different botanic origin. The e-tongue presented here is based on the small-signal frequency response of the electrical double-layer established between the honey solution and an array of four different sensing units composed by gold, carbon, indium-tin-oxide, and doped silicon. The ability of the e-tongue to discriminate honey of different floral origins was demonstrated by distinguishing honey from Bupleurum and Lavandula pollen prevalence. The honey fingerprint obtained with the e-tongue was validated by parallel melissopalenogical analysis and physico-chemical methods. It is demonstrated that the e-tongue is very sensitive to changes on the honey electrical conductivity. Small differences in electrical conductivity are introduced by the presence of ionisable organic acids and mineral salts. Moreover, we propose that the sensitivity of the tongue to changes in electrical conductivity can be explored to probe other complex liquid substances.
- Physicochemical characteristics and antiproliferative and antioxidant activities of Moroccan Zantaz honey rich in methyl syringatePublication . Elamine, Youssef; Lyoussi, Badiâa; Miguel, Maria da Graça; Anjos, Ofélia; Estevinho, Leticia M.; Alaiz, Manuel; Girón-Calle, Julio; Martín, Jesús; Vioque, JavierZantaz honey is a monofloral variety produced from the melliferous plant Bupleurum spinosum (Apiaceae), a shrub that grows mainly in the Atlas Moroccan Mountains. Determination of the polyphenol composition revealed that methyl syringate accounts for more than 50% of total polyphenols, which represents a very useful parameter for the characterization of this monofloral honey. Epicatechin, syringic acid and catechin are also abundant. Caco-2 and THP-1 cells were used for determination of antioxidant and antiproliferative activities in Zantaz honey, respectively. All six commercial samples that were used for these studies exhibited antioxidant activity and inhibited cell proliferation. Interestingly, these activities had a positive correlation mainly with the content in methyl syringate and gallic acid. The recognition of health promoting activities in Zantaz honey should increase its commercial value, which would have a positive economic impact on the poor rural communities of Morocco where it is produced.
- Physicochemical characterization and antioxidant activity of honey with Eragrostis spp. pollen predominancePublication . Aazza, Smail; Elamine, Youssef; El-Guendouz, Soukaïna; Lyoussi, Badiâa; Antunes, Maria Dulce; Estevinho, Leticia M.; Anjos, Ofélia; Carlier, Jorge D.; Costa, Maria Clara; Miguel, Maria da GraçaThis study aimed to characterize the pollen and physicochemical profiles, and to evaluate the antioxidant capacity of six samples of Moroccan honey. The pollen grains of Eragrostis spp. were predominant in all samples (from a minimum of 46.58 ± 1.59% to 72.72 ± 2.43% as a maximum), exceeding the minimum (generally 45%) required for the monoflorality nomination of a honey sample, and suggestion a case of newly reported honey. The analyzed samples had low diastase activity and hydroxymethylfurfural (HMF) content. Potassium was the dominant element in practically all samples, except the sample with the highest Eragrostis spp. pollen percentage, which showed sodium predominance. The honey color ranged from water white to light amber, and positively correlated the concentrations of phenols, proline and the capacity for scavenging free radicals. However, great variability observed in all the analyzed parameters, and could not be explained by the variability of the Eragrostis spp. pollen percentage, which suggests a hypothesis of low concentrated nectar. Practical applications: The melissopalynological profile of honey is an important parameter for determining the type of honey (multifloral, monofloral, blossom, honeydew) and its relationship to the botanical and geographical provenance. There is generally a relationship between the pollen profile of honey and the biological properties. The physicochemical characterization, antioxidant activity and melissopalynological profile of Eragrostis honey was reported for the first time in this study. These data intend to contribute for the introduction of a new type of honey labeled as Eragrostis honey. At the same time, the evaluation of the antioxidant activity may also trigger the search of other biological properties with medicinal attributes for the new Eragrostis ssp. honey.
- Preliminary characterization of a Moroccan honey with a predominance of Bupleurum spinosum pollenPublication . Elamine, Youssef; Aazza, Smail; Lyoussi, Badiâa; Antunes, Maria Dulce; Estevinho, Leticia M.; Anjos, Ofélia; Resende, Mafalda; Faleiro, Maria Leonor; Miguel, Maria da GraçaHoney with Bupleurum spinosum (zandaz) as a main pollen source has not been the subject of previous detailed study. Therefore, twelve Moroccan samples of this honey were subjected to melissopalynological, physicochemical and microbiological quality characterization, as well as antioxidant activity assessment. From a quality point of view, almost all samples were within the limits established by Codex Alimentarius, and/or the European legislation. All samples presented predominance of B. spinosum pollen (more than 48%). Relatively high levels of trehalose (1.3–4.0 g/100 g) and melezitose (1.5–2.8 g/100 g) were detected. Those sugars, not common in monofloral honeys, could be used as an important factor to discriminate zandaz honey. Flavonoid content correlated positively with the honey color, melanoidin and polyphenol content, and negatively with the IC50values of scavenging ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) free radicals, while proline amount correlated negatively with IC50values of nitric oxide scavenging activity and chelating power. This correlation supports the use of anti-oxidant activities as important variables for PCA (principal component analysis). Both components explained 70% from the given data, and showed certain homogeneity upon analyzed samples independent of the region, suggesting the importance of B. spinosum nectar in the resulting honey characteristics.
- Volatile characterization of honey with dominance of Bupleurum spinosum pollenPublication . Elamine, Youssef; Machado, Alexandra M.; Estevinho, Leticia M.; Lyoussi, Badiâa; Figueiredo, Ana Cristina; Miguel, Maria GraçaMoroccan honey with Bupleurum spinosum (Apiaceae/Umbelliferae) as the main pollen source is locally known as Zantaz honey. In the present work, the volatiles from 18 honeys of this type, were isolated by hydrodistillation and analysed by Gas Chromatography (GC) and Gas Chromatography-Mass Spectrometry (GC-MS), for volatiles quantification and identification. The percentage composition of the volatiles and pollen profiling was used to determine the relationship between the different samples by cluster analysis. Two poorly correlated clusters were defined in volatiles analysis. Cluster A, with 17 out of the 18 samples, included four subgroups dominated by straight-chain hydrocarbons and fatty acids in variable proportions. Cluster B included just one sample, with 1-phenyldodec-1-en-3-one as the main component. Mono- and sesquiterpene hydrocarbons, as well as oxygen-containing mono- and sesquiterpenes occurred always <2%. Two moderately correlated clusters were defined after pollen profiling cluster analysis. Pollen Cluster A included 17 samples having in common the presence of B. spinosum and Populus sp. pollen. The one sample from Cluster B was moderately correlated with Cluster A and showed the lowest percentage of B. spinosum pollen. Pollen volatiles analysis would be relevant in assessing the presence of putative pollen volatile marker compounds and the importance of pollen profile on honey volatiles.
- Zantaz honey “monoflorality”: chemometric applied to the routinely assessed parametersPublication . Elamine, Youssef; Lyoussi, Badiâa; Anjos, Ofélia; Estevinho, Leticia M.; Aazza, Smail; Carlier, Jorge D.; Costa, Maria Clara; Miguel, Maria da GraçaThe comparison of Zantaz honey samples harvested in Morocco in two different years was performed through chemometric analysis of routinely assessed parameters. The objective was to study how the pollen profile of this newly reported honey shapes its physicochemical characteristics as well as to determine its monoflorality threshold, which has not yet been defined. The predominance of B. spinosum pollen was confirmed in the majority of samples reaching 45%, generally requested for monoflorality declaration. The principal component analysis (PCA) was used for clustering and variables correlations. Pollen qualitative and quantitative differences could discriminate the samples belonging to both seasons when combined with the sugar analysis (59.44%) better than the combination with physicochemical parameters (pH, acidity, ash content, electrical conductivity and color) (60.62%). Positive correlation between the presence of B. spinosum pollen and melanoidins, color, fructose, moisture, trehalose, melezitose, iron, manganese and calcium could be seen. Integrating all the parameters except the pollen data allowed distinguishing two groups with significant differences (P < 0.05) in B. spinosum representability (58 ± 11.24% against 40 ± 15.98%). This may suggest that 40% is the monoflorality threshold of the Moroccan Zantaz honey, although a confirmation with sensorial analysis is required.