Honey variety is commonly defined by beekeepers based on nectar flow availability and the only laboratory method to provide verification is the melissopalynological analysis. Therefore, a quick and simple method for accurate assessment of honey variety is still being researched. The aim of the study was to evaluate the antioxidant activity of honey as an indicator of variety through the use of multivariate statistical analysis. Materials for the study consisted of 90 samples of varietal Polish honeys (rape-12, tilia-10, goldenrod-11, dandelion-5, buckwheat-6, multifloral-17, nectar-honeydew-8 and coniferous honeydew-16 and leafy honeydew-5) obtained directly from apiaries. Honeys were investigated in aspect of antioxidant capacity by photochemiluminescence (PCL) methods using standard ACW and ACL kits. As the reference FRAP and DPPH methods were used. The total phenolics content (TPC) was determined through the Folin-Ciocalteu method. The strongest antioxidant activity was found for buckwheat, while the weakest was found for rape honeys regardless of the used method. Results of the used methods were positively correlated (r = 0.42 to 0.94). Analysis conducted by PCL method confirmed that the minor fraction of honey antioxidants exhibits hydrophobic properties. Clear separation of honey varieties using PCA and Clustering method indicate that antioxidant activity can be a useful parameter for determining the botanical origin of honey.

Honey composition is mainly affected by botanical origin, however geographical factors as well as beekeeping practice and storage conditions can also influence its quality. The aim of the study was to determine the impact of geographical origin on physicochemical quality and biological activity of honey. For this reason Polish and Slovak varietal honeys, including per each country: 10 multifloral, 5 tilia, 5 rape, 5 acacia and 5 forest were compared according to their physicochemical parameters (free acidity, pH, electrical conductivity, moisture content, and colour intensity), sugar profile, diastase activity, as well as antioxidant activity (DPPH and FRAP tests, as well as photochemiluminescence method). Moreover, total phenolics compounds and flavonoids content were determined. The most significant differences (P < 0.05) between Polish and Slovak counterparts were found for tilia while the lowest for rape honeys. The impact of geographical origin on overall quality of honey was proved by PCA statistical tool.

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Two various species of mulberry (Morus sp.) were selected to enrich rape honey with dried leaves or lyophilized fruits (4% w/v). Finally, fruits and leaves of the 'Ukraińska' clone were introduced into the honey during creaming in concentrations from 1 to 4% w/v. The total phenolic content, antioxidant activity, anthocyanins content, and polyphenolic profile were tested in plant extracts and enriched honeys. Moreover, α-glucosidase, β-galactosidase, and diastase activities were investigated in honeys. For mulberry extracts, chlorogenic acid isomers and rutin were considered main antioxidant compounds. The antioxidant activity of honey enriched with mulberry leaves increased even more than 50 times, due to introducing numerous phenolic acids and flavonoid glycosides. A significant decrease in the diastase activity in honey depending on the content of added mulberry leaves (almost 50% decrease in the case of 4% addition) was found, suggesting the inhibitory effect of honey with mulberry leaves against carbohydrate hydrolyzing enzymes.

Fir honeydew honey is a uniquely beneficial product which is often subjected to adulteration; however, pollen analysis is not useful to verify this honey type. Fourteen samples of EU protected designation of origin fir honeydew honey gathered directly from apiaries were studied. Standards of legal requirements and additional parameters, i.e., specific optical rotation, mineral content, and antioxidant activity, were tested. Five nectar honeys of different varieties were used as a comparative material. HPTLC and SDS-PAGE methods were used to fingerprint the honey types. All honeys tested fulfilled the quality requirements in terms of water content, pH, total acidity, conductivity, HMF, and diastase number. They were defined as dark amber on the Pfund scale and exhibited positive specific rotation (+2.5 to 25). Honeydew honey surpassed the tested nectar honeys in terms of mineral content and antioxidant activity as well as total polyphenolic content, except for buckwheat honey. The sugar and polyphenolic profile obtained by HPTLC allowed to distinguish honeydew from nectar honeys. The same was achieved by SDS-PAGE protein profiling. Both techniques seem to be cheap and quick tools for precisely distinguishing honeydew honey.

AbstractThe transfer of toxic metals from soil to honey was studied based on two different areas of the Podkarpackie region located in the south-east part of Poland: U-urbanized and E-ecologically pure. The metal content was determined using the ICP-OES method with prior microwave mineralization of the soil, plant (goldenrod, dandelion, rapeseed, tilia and fir), bee bodies and honey samples collected from 10 sampling points (U-5 and E-5). The impact of soil pH on heavy metal mobility was also evaluated. It was found that Podkarpackie soils are less contaminated with heavy metals as compared to other regions of Poland and only in the case of cadmium an enhancement of the natural background level was observed. The migration of heavy metals, especially cadmium, in the soil-plant-bee-honey food chain was accelerated by soil acidity (p<0.05). The influence of human activity (region development) on heavy metals concentrations was not significant (p>0.05). Based on bioaccumulation factors, goldenrod and dandelion plants were confirmed as cadmium accumulators. It was also confirmed that the bodies of bees act as an effective barrier to the migration of heavy metals from the environment to honey, due to this, honey is free from these metals and safe for human consumption.

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