Workpackage 1

The aim of the Honey Department in the Beeshop project is 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. The Honey Department focused also on physiological properties of honey which can be beneficial for the colony itself and for the prevention of honeybee diseases.
Seventy samples of unifloral honey from 18 different botanical origin were collected from beekeepers in Italy, France, Slovakia and Czech Republic. Samples were analysed for verification of the botanical origin by the traditional chemico-physical, palynological and sensorial methods. They were then submitted to analyses for the presence of phytochemical markers specific for the botanical origin, the presence of protein components which can be important for the determination of honey quality and authenticity, the evaluation of honey quality in respect of description and production and the evaluation of antibacterial properties and anti quorum-sensing activities.

By HPLC analysis suitable markers were detected for Robinia, Tilia, Citrus, Eucalyptus and Castanea unifloral honeys. 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.

A new, rapid, reproducible and sensitive enzyme-linked immunoassay (ELISA) of quantitative determination of predominant of RJ protein apalbumin1 in honey has been developed. The concentration of apalbumin1 in different honeys demonstrated a variability originated mainly from the botanical origin. The highest content of apalbumin1 was determined in chestnut honey, in comparison with acacia honey and rape honey. This test has a potential of wide application to prove the identity of honeys, to reveal their adulteration with low-cost syrups and for the quantitative determination of the apalbumin1 protein in honey, pollen and RJ.

Two new techniques were introduced for the evaluation of botanical origin and for the detection of adulteration of honey by sugar syrups: Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) and High Resolution Nuclear Magnetic Resonance (HR-NMR). The two techniques resulted to be suitable both for the verification of botanical origin and the detection of honey adulteration by sugar syrups.

Antibacterial activity of honey was evaluated from 3 different point of view.

• The antibacterial activity of selected Italian honeys was tested by agar well diffusion method against pathogenic and non-pathogenic bacteria isolated from the bee hive. Melissococcus plutonius resulted the most sensitive to the antimicrobial power of honey. The antibiotic activity was significantly lower for the strain of Paenibacillus larvae isolated from a bee hive. This could be explained as a drug resistance effect due to the widespread use of antibiotics throughout the area of the samples collection.


• 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 only in protein fraction of cherry and rape honeys and honeydew. Despite of this, a protein fractions corresponding to apalbumin2a have been identified in honey, which demonstrated antibiotics properties against P. larvae.


• The anti quorum-sensing (anti-QS) activities of honeys with different floral origin were evaluated using bacterial strains, in which quorum sensing activated the pigment violacein. Both well diffusion methodology and liquid culture methodology were used. The anti-QS activity was concentration-dependent as the inhibition activity increased with increased honey concentration. Among all honeys, chestnut and linden samples were the strongest QSI. It was observed that no relationship between either the total and individual phenolic content, or the antipathogenic activities of honeys was observed. Thus, other non-phenolic compounds associated with floral origin could be responsible for the anti-QS activity.