![]() ![]() A reference collection of CIMO-Mountain Research Centre (Agricultural College of Bragança) and different pollen morphology guides were used for the recognition of the pollen types. ![]() Pollen grain identification was performed by optical microscope with total magnification (400× and 1000×). Then acetolysis was applied, and two additional microscope slides were prepared using glycerin jelly, one stained with basic fuchsine and the other without stain. In this stage, three propolis microscope slides were mounted with sediment obtained after centrifugation (10,000× g for 1 min) for observation of plant trichomes and other organic residues that may be destroyed in sequence. Next, the sediment was treated with KOH (10%), sonicated for 15 min and sieved through a 20 mesh stainless steel screen to eliminate large fragments. In brief, 0.5 g of scraped propolis was extracted overnight with ethanol. ![]() ![]() Palynological processing of the samples followed the standard methodology, described in detail previously. Indeed, the composition of propolis is highly variable due to the diversity of plants around the hive from which the bees collect the exudates. These differences are due to different botanical and geographical origins. Concerning the waxes and the soluble solids, the first were higher and the second were much lower than those obtained in the present study. obtained similar values for moisture and ash, even though great differences were found among the Brazilian samples studied. , who studied propolis samples from four different cities of Portugal. These results are corroborated by the values obtained by Dias et al. The values obtained in the present study for the physicochemical parameters are presented in Table 2. More recently, however, parameters like moisture, insoluble and soluble substances, pH, conductivity, ash and waxes have received attention. Studies concerning the physicochemical characteristics of propolis have often focused on the presence of polyphenols and flavonoids. ![]()
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