Logo do repositório

Percorrer por autor "Kaid, Seloua"

A mostrar 1 - 1 de 1
  • Quality evaluation of Algerian honeys: Eucalyptus, Jujube, Euphorbia and multiflora
    Publication . Kaid, Seloua; Vilas-Boas, Miguel; Falcão, Soraia; Ziani, Kaddour
    This study was intended to evaluate the quality parameters of ten honey samples, from various regions in semi-arid region of Algeria. Different parameters such as the melissopalynological and the physicochemical properties of the honeys (moisture, color, electrical conductivity, 5-hydroxymethylfurfural, pH, acidity, proline, and diastase activity) were determined, as well as the evaluation of sugars, minerals and phenolic compounds. Nutritional composition, antioxidant activity (reducing power and DPPH free radical scavenging activity), anti-inflammatory and cytotoxicity were also evaluated. Finally, antibiotics residues such as sulphonamides and tetracyclines antibiotics residues were screened. The melissopalynological results identified ten types of pollen, with Cytisus striatus pollen being identified as the most abundant, present in all samples with percentages between 26.0 % and 83.8 %. EC1, MF1 and MF2 (Sidi Belabes region) were classified as monofloral of Cytisus striatus honey. Additionally, although samples J1 to J3 were not considered as Jujube monofloral, they showed a high percentage of Ziziphus pollen. The remaining samples (EC2, EF1, EF2, and EF3) were classified as multifloral. Regarding the physicochemical parameters, no significant differences were found in the color of the samples which ranged between amber, light amber and extra light amber. Moisture content was found to be between 13.6% (EF1) and 18.3% (EC1), while pH values ranged between 4.2 and 5.1. Electrical conductivity values varied between 270 and 410 μS.cm-1, while 5- hydroxymethylfurfural content showed values between 0 and 36.5 mg.kg-1 and diastase values between 8.8 DN and 13.3 DN. Concerning the proline content, the samples showed proline levels between 2.2–4.7 mg/kg, indicating a good maturity of the honeys and absence of adulteration. All the honeys meet the standard required by the European legislation with exception of the diastase index. The sugar profile, analyzed by high pressure liquid chromatography with refractive index detection (HPLC-RI), showed that all samples have higher fructose content than glucose, being the total more than 88.70 %, allowing the classification of all the samples as nectar honeys. Within the minerals, potassium was quantitatively the most important mineral (72.93% of total minerals quantified), having an average content 730.59mg/kg, followed by sodium, calcium and magnesium, with 17.05%, 4.43% and 4.22%, respectively, while cadmium and lead had the lowest concentration, 0.003 % and 0.04% respectively. The total phenolic content of the analyzed honey samples ranged between 0.7 mg GAE/g, for samples EF and J and 1.4 mg GAE/g, for samples EC, with an average of 0.9 mg GAE/g. The total flavonoid content varied from 0.03 to 0.09 mg QE/g with the highest levels observed in J honey samples. The values obtained for DPPH ranged from 0.02 to 0.04 mg/mL, without significant differences between the samples. The analysis of the phenolic profile was performed by UPLC/DAD/ESI-MSn, where nineteen phenolic compounds were identified, including six phenolic acids, nine flavonoids, two isoprenoids (abscisic acid isomers), one phenolic diterpenoid (carnosol) and one spermidine (N1, N5, N10-tri-p-coumaroyespermidine). The major quantity of phenolic compounds was found in sample EC1 with 202 mg/100 g, while sample EF3 showed the lowest amount with 59.85 mg/100 g. Concerning the anti-tumoral evaluation, all the studied extracts presented good activity, with MF1 showing the highest cytotoxicity, followed by EF1. Also, all the extracts under study showed anti-inflammatory capacity, with IC50 values between 8 and 400 μg/mL. Regarding the antibiotics residues, its presence was found in three of the samples (MF1 EF1 EF3) showed positive results for sulphonamides residues.
    2021Dissertação de mestrado Acesso aberto Ver mais