Palynological and geographical characterisation of Spanish oak honeydew honeys

Abstract

The emergent market for honeydew honey mostly in Europe has prompted increasing requirements by consumers and the honey industry for the characterisation of this type of honey. This work is a contribution to the limited knowledge of honeydew honeys in Spain. Botanical characterisation was performed on 59 honeydew honey samples from professional beekeepers hives distributed within Spain. The quantitative analysis reveals more than 75% of the samples belong to Maurizio Classes II and III, and that, in general, the Spanish Quercus honeydew honeys are characterised by medium high pollen grain content (Pn; mean = 285 197) and honeydew elements (HDEs; mean = 15 850). The analysis also resulted in the identification of spores of several fungal genera (Alternaria, Cladosporium, Drechslera, Geotrichum, Phithomyces, Stemhylium, Torula, Ulocladium and Venturia). All honey samples had a smaller ratio of honeydew elements to pollen grain content (mean HDE/Pn = 0.12), and for the majority of samples (93%) the ratio HDE/Pn was very low (< 0.3), suggesting that this traditional ratio value should not be considered as an indicator of honeydew honeys. The qualitative analysis of the samples showed the presence of 73 taxa belonging to 38 families. Pollen grains of Quercus f., Rubus ulmifloius f., Campanula erinus gr., Capsella f., Cytisus scoparius f., Echium plantagineum gr., Cistus ladanifer f. or Castanea sativa, and, to a lesser extent, those of Crepis f.,Eucalyptus f., Senecio f., Halimium f., Erica australis, Plantago f., Salix triandra gr. and Centaurea calcitrapa gr. are representative of Spanish oak honeydew honeys.