Honey is considered a natural sweet substance produced by honeybees, from the nectars of plant flowers and honeydews. Honey has always been regarded as a food that is beneficial for human health with several therapeutic qualities described. The quality of honey is still a top concern for experts as no good method has been defined so far for the simultaneous detection of different types of honey. Consequently, the development of easy, quick, precise analytical tools that may give data for assessing honey authenticity, is important. Because of that, it is essential to inform consumers of the mislabeling of honey with lower quality. This study aimed to evaluate the physicochemical characteristics and to assess the quality of Algerian honey from different botanical and geographical origins. For that, ten samples of honey with different marked botanical origins were analyzed, including three samples from rosemary honey, three from tamarisk honey, three from milk thistle honey and one multiflora honey. The quality of the samples was determined through different parameters. Melissopalynological and physicochemical analyses (color, moisture, pH, acidity, electrical conductivity, diastase index, proline, 5-hydroxymethylfurfural, mineral content, proteins, carbohydrates, energy, and ash) were performed, as well as the profile evaluation of sugar and phenolic compounds. Antioxidant activity (reducing power and DPPH free radical scavenging activity) antitumor and anti-inflammation activity were also evaluated. Finally, the presence of antibiotics, recurrent residues in honey, such as tetracyclines and sulphonamides were screened using the multi-analyte receptor assay system Charm II.
The melissopalinological analysis showed the presence of 10 major types of pollen grains, with Rosmarinus officinalis, Cytisus stratitus and Centaurea sp. pollens as the most abundant. Furthermore, since no honeydew elements were detected, all the samples were classified as nectar honeys. Samples R1, R2, and R3 were classified as rosemary monofloral honey; samples T1, T2 and MF were classified as Cytisus striatus honey; CH1-CH3 were classified as Centaurea sp. and T3 as multifloral, which not always agreed with the labeled botanical origin.
Generally, honey samples presented values of moisture, free acidity, 5-HMF, proline content, and diastase index within the limits of the legal requirements, suggesting that the honey was extracted at a correct ripeness stage. The results showed that almost all honey samples have light amber color, except the rosemary honeys which presented an extra white amber color. Although exhibiting a normal diastase index, the R2 and R3 samples presented a 5-HMF value higher than the admitted in the legislation, suggesting that less adequate heat treatments and/or conservation methods might have been employed. The most common minerals were potassium, sodium, calcium, manganese, while copper and Manganese were present in some samples in minor quantities and the heavy metals (cadmium and lead) are absent from all samples. The sugar profile, analyzed by high pressure liquid chromatography with refractive index detection (HPLC-RI), showed that fructose and glucose were the most abundant compounds, representing more than 60% of total sugars. Other sugars, such as turanose, maltulose and maltose were also detected in a lower proportion. Regarding the phenolic profile, nineteen compounds (eight phenolic acids and seven flavonoids), two isoprenoid compounds (trans, trans- and cis, trans- abscisic acid), one spermidine and one phenolic diterpene were identified. T2 sample showed a higher amount of phenolic acids than flavonoids. However, the most abundant compounds were the benzoic acid derivative which was detected in all samples. Concerning the evaluation of the antitumor activity and anti-inflammatory activity the samples showed a significant potential. Finally, concerning the antibiotics screening, not all the samples showed negative results.
