The identification of botanical and zoological origins of different honeydew honeys

Honeydew honey is produced by bees from excretions – the honeydew – of plant-sucking insects. Honeydew can be produced by different insect-species, such as the genera Cinara and Physokermes on conifers and the genera Eucallipterus on lime trees. Therefore, honeydew honey can stem from different botanical as well as different zoological origins. In order to investigate the process from phloem sap to honeydew, honeydew samples from different Hemipteran species were collected and the sugar, amino acid, and inorganic ion profiles were determined. Honeydew from all species contains different proportions of hexoses, sucrose, melezitose, erlose, and trehalose, whereas the phloem exudates of the host trees contain no trisaccharide. That was confirmed by incubating whole-body homogenates of different aphid species with sucrose, the outcome of which was melezitose and erlose. Additionally, the classification of honeydew samples on the basis of their sugar profiles showed that the proportions of sugars differed significantly between different hemipteran species feeding on the same tree species. Moreover, statistical analyses reveal that the sugar composition of honeydew is determined more by the hemipteran species than by the host plant. In order to identify the botanical and zoological origin of honeydew honey, fir, spruce, and pine honey samples were collected and analyzed. Fir and spruce samples were collected in different locations in south Germany, pine honey samples were collected in Turkey. Pine honeys can be separated from fir and spruce honey because of their high contents of (undef 3) sugar and inorganic ions. In addition, fir and spruce honey can be divided in three groups: Physokermes/spruce, Cinara/spruce, and Cinara/fir. Physokermes/spruce honey also has a significantly higher content of phosphate and (undef 6) sugar than the other two honeys. To reliably distinguish between fir/Cinara and spruce/Cinara honey, however, no chemical marker was found within the analyzed compounds. In order to clarify the origin of linden honey, sugars, amino acids, and inorganic ions, profiles for honeydew, nectar, and honey from Tilia sp. were determined. Melezitose and erlose were determined in the honeydew and in the honey, but not in the nectar. In addition, the incubation of whole-body homogenates of different aphid species with sucrose, resulting in melezitose and erlose, confirmed our results. Finally, the ability of honeybees’ cleavage enzymes to digest melezitose was also investigated. Honeybees’ abdomen enzymes are able to cleave melezitose and produce glucose and fructose; this process, however, is not as efficient as the cleavage of sucrose.