THE QUALITY OF HONEY FOR BEES AND MAN

Honey is used both as food ingredient and in a variety of treatments for diverse ailments. For this reason, consumer expectation of its quality and purity is particularly high. The aim of the BEE SHOP Honey Department was the evaluation of honey quality and authenticity, through the development of new instrument for the verification of the botanical origin and the presence of impurities. Honey quality can be important also for the colony itself and therefore the Honey Department focused on the physiological properties of honey which can be beneficial for honeybees and for the prevention of bee diseases. Testing the origin of honeybees is also important to enforce the EC directive for organic beekeeping, since the use of regional bee strains is an important quality criterion for organic honey. To identify the origin of the honeybee the BEE SHOP Honey Department has developed a DNA based diagnostic tool. Through the analysis of honey and nectar samples by HPLC-MS-MS methods, suitable markers were detected for Robinia, Tilia, Citrus, Eucalyptus and chestnut unifloral honeys, and the following phytochemicals have been proposed for the determination of honey floral origins: myricetin, tricetin and luteolin for Eucalyptushoney, kynurenic acid related compounds for chestnut honey, terpenoids for Linden honey, hesperetin for Citrus honey, kaempferol rhamnosides for Acacia (Robinia) honey. Two novel protocols were introduced for the evaluation of honey quality: DRIFTS (Diffuse Reflectance Infrared Fourier Transform Spectroscopy) and HR-NMR (High Resolution Nuclear Magnetic Resonance). These techniques, coupled with appropriate multivariate statistical analysis, demonstrated to be suitable for the verification of botanical origin and the detection of honey adulteration by sugar syrups. The HR-NMR method seems to be suitable also for a quantitative determination of the adulteration levels. A new sensitive enzyme-linked immunoassay (ELISA) for the quantitative determination of apalbumin1a major compound of the royal jelly (RJ) proteins in honey has been developed. This protein can be used as a marker for honey quality because its concentration varies with the botanical origin. The highest content was determined in chestnut honey, in comparison with acacia and rape honey, while the lowest amount was detected in honey obtained supplying bee colony with saccharose syrup. The antimicrobial potential of honey based on proteins of honeybee origin was tested by microtiter based assays. The inhibition of P. larvae growth was observed in the protein fraction of cherry and rape honeys and honeydew. Moreover, a protein fraction corresponding to apalbumin2a has been identified in honey. This protein, purified from RJ, had specific antibiotic properties against P. larvae. The anti quorum-sensing (QS) activities of honeys with different floral origin have been evaluated, using bacterial strains in which quorum-sensing activated the pigment violacein. 29 honey samples inhibited QS even at the lowest concentration. The anti-QS activity was concentration-dependent and relied on the floral origin. Among all honeys, chestnut and linden samples were the strongest quorum-sensing inhibitors (QSI).