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Characterization of volatiles from Moroccan propolis samples

Publication . EL-GEUNDOUZ, Soukaina; Lyoussi, Badiaa; Miguel, Maria Graca; Figueiredo, A. Cristina

The volatiles from 24 propolis samples collected from different geographical locations in Morocco were evaluated. Propolis volatiles isolated by hydrodistillation and analyzed by gas chromatography (GC) and gas chromatography–mass spectrometry (GC-MS). Cluster analysis based on propolis samples’ volatile chemical composition defined two main uncorrelated clusters. Cluster I, with 23 of the 24 samples analyzed, included three subgroups, Ia, Ib1 and Ib2, dominated by βeudesmol (11–30%), cedrol (7–40%) and n-tricosane (6–34%), respectively. Cluster II included just one sample, with ar-curcumene (32%) as the main component. The results obtained contributed to increase the knowledge on the chemical composition and variability of Moroccan propolis samples. The volatile profile of these samples was distinct from those of Algeria, Canary Islands and Ethiopia, the sole African propolis volatiles studied so far.

2018Journal article

Restricted

Physicochemical characterization and antioxidant activity of honey with Eragrostis spp. pollen predominance

Publication . AAZZA, Smail; Elamine, Youssef; EL-GEUNDOUZ, Soukaina; Lyoussi, Badiaa; Antunes, Maria Dulce; Estevinho, Leticia M.; Anjos, Ofélia; Carlier, Jorge; Costa, Maria C.; Miguel, Maria

This 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 46.581.59% 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 applicationsThe 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.

2018-02Journal article

Open Access

In-vitro antioxidant and anti-inflamatory activities of Pituranthos chloranthus and Artemisia vulgaris from Tunisia

Publication . Ben Nasr, Soumeya; AAZZA, Smail; Mnif, Wissem; Miguel, Maria

Pituranthos chloranthus and Artemisia vulgaris L. are two of the most important aromatic and medicinal species from the Apiaceae and Asteraceae families, respectively. They are traditionally used in certain pathologies in which inflammatory processes are involved. The present study investigates the potential of aqueous extracts of Tunisian P. chloranthus and A. vulgaris as a natural alternative source of antioxidant and anti-inflammatory activities using in-vitro techniques. The antioxidant activities of aqueous extracts were evaluated through several assays: capacity for scavenging free radicals (ABTS, DPPH, hydroxyl, superoxide, nitric oxide); and total antioxidant capacity by ferric reducing power activity and inhibition of lipid peroxidation by thiobarbituric acid reactive species (TBARS) method. The anti-inflammatory activity was evaluated through the lipoxygenase (LOX) inhibitory activity. P. chloranthos aqueous extract presented higher concentration of total phenols than A. vulgaris extract, nevertheless higher capacity for scavenging ABTS, superoxide, hydroxyl. and NO free radicals. In the presence of liver homogenate, both extracts had poorer antioxidant activity than in the remaining lipid substrates. P. chloranthos extract had a higher ability for inhibiting lipoxygenase twice higher than A. vulgaris, while it had lower capacity for reducing Fe3+ than P. chloranthos extract. Our results suggest that there are differences of antioxidant activity between both samples, but also the strength for inhibiting the oxidation is highly dependent on the method used.

2020Journal article

Open Access

Changes in the chemical parameters during the production of água-mel from Portugal

Publication . Miguel, Maria; AAZZA, Smail; Antunes, Maria Dulce; Faleiro, Maria Leonor

Agua-mel is a honey-based traditional product typically produced in southern Portugal. The evolution of some parameters during its production using two distinct containers (aluminium and stainless steel with a water cooling system) and two heating sources (gas heating and electricity) were evaluated. All parameters, except moisture, increased over time, reaching a 'plateau' after 8 h of heating. Moisture, free acidity, HMF (hydroxymethylfurfural), colour, melanoidins, phenols and glucose depended on the producer and procedure for obtaining agua-mel. Kinetic parameters and correlation coefficients were determined. In general, changes in parameters during agua-mel production followed zero- and/or first-order kinetics, depending on the producer and heating system.

2018Journal article

Open Access

Honey volatiles as a fingerprint for botanical origin: a review on their occurrence on monofloral honeys

Publication . Machado, Alexandra M.; Miguel, Maria; Vilas-Boas, Miguel; Figueiredo, Ana Cristina

Honeys have specific organoleptic characteristics, with nutritional and health benefits, being highly appreciated by consumers, not only in food but also in the pharmaceutical and cosmetic industries. Honey composition varies between regions according to the surrounding flora, enabling its characterization by source or type. Monofloral honeys may reach higher market values than multifloral ones. Honey's aroma is very specific, resulting from the combination of volatile compounds present in low concentrations. The authentication of honey's complex matrix, according to its botanical and/or geographical origin, represents a challenge nowadays, due to the different sorts of adulteration that may occur, leading to the search for reliable marker compounds for the different monofloral honeys. The existing information on the volatiles of monofloral honeys is scarce and disperse. In this review, twenty monofloral honeys and honeydews, from acacia, buckwheat, chestnut, clover, cotton, dandelion, eucalyptus, fir tree, heather, lavender, lime tree, orange, pine, rape, raspberry, rhododendron, rosemary, strawberry tree, sunflower and thyme, were selected for volatile comparison purposes. Taking into consideration the country of origin, the technique of isolation and analysis, the five main volatiles from each of the honeys are compared. Whereas some compounds were found in several types of monofloral honey, and thus not considered good volatile markers, some monofloral honeys revealed characteristic volatile compounds independently of their provenance.

2020Journal article

Open Access