Bortolotti, L.; Truchado, P.; Allende, A.; Kaatz, H.-H-.; Bertelli, D.; Plessi, M.; Bíliková, K.; Šimúth, J.; Moritz, R. F. A.; Tomás-Barberán, F. A.; Sabatini A. G.
|Riassunto in Inglese:|
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 Honey Department focused on the physiological properties of honey which can be beneficial for honeybees and for the prevention of bee diseases.
Through the analysis of BEE SHOP 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 Eucalyptus honey, 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 and HR-NMR. 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.
Testing floral origin is only one aspect of a honey quality assay; 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. The BEE SHOP Honey Department has develop highly specific antibodies against royal jelly proteins, which are added to the honey by each worker bee during nectar processing, to identify the origin of the honeybee.
Thus, honey contains also proteins, and among them apalbumins, the major proteins of royal jelly (RJ). A new sensitive enzyme-linked immunoassay (ELISA) for the quantitative determination of apalbumin1 in honey has been developed. This protein can be used as a marker for honey quality because its concentration vary 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 assay. An inhibition of P. larvae growth was observed in protein fraction of cherry and rape honeys and honeydew. Moreover, a protein fractions corresponding to apalbumin2a has been identified in honey. This protein, purified from RJ, demonstrated antibiotics properties against P. larvae.
The anti quorum-sensing (QS) activities of honeys with different floral origin has been evaluated, using bacterial strains in which quorum sensing activated the pigment violacein. 29 honey samples inhibited the AHL production, 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 QSI.