Fungal Diversity and Over-Represented Non-Nectariferous Plants Pollen in Honey. Case Study on Acacia Honey Authenticity, Analyzed in APHIS Laboratory

Pollen analysis is the basic method for the determination of the botanical and geographical origin of honey. However, the presence of over-represented pollen in honeys may lead to false results of the analysis. This can be more severe if this pollen is present in unifloral under-represented honeys of commercial importance (e.g. thyme or acacia honey). In the present study, we investigated the abundance of nectarless pollen grains on several quality characteristics in honey samples. In particular, the physic-chemical (diastase activity, electrical conductivity, sugars and HMF content) analysis were carried out in order to confirm the declared botanical origin. Spectrophotometric method was used for diastase activity determination, electrical conductivity was determined by potentiometry and chromatographic determinations for HMF content (photodiode array detection) and sugars (HPLC refractive index detection). The present study confirms that, in the case of non-nectariferous pollen presence in honeys, a second count must be made, excluding this pollen type and pollen analysis alone cannot give reliable results for the determination of the botanical origin. Consequently, pollen analysis should be combined with other analyses, especially in honeys with under-represented pollens, to give precise results for the botanical characterization and labeling of honeys.