Melezitose, also spelled melecitose and melicitose, is a trisaccharide sugar that occurs in the honeydew of many sap trees such as larch, lime tree, poplar, and Douglas fir, and also in honey. It is produced enzymatically by many plant sap eating lice, such as Cinara pilicornis. The name is by the French chemist Berthelot, who first isolated it from larch honeydew in 1856.

Function

Melecitose can be hydrolyzed with acid to glucose and turanose, a sucrose isomer. It is beneficial to the insects, as it reduces the stress of osmosis by reducing their own water potential. Melecitose attracts ants and is also eaten by bees and incorporated into honey, although it is not easily digested by bees.

Honey with a high melecitose content (honeydew honey, "cement honey") crystallizes in the honeycomb and cannot be extracted with centrifuging, but must be dissolved in much water. It is therefore less suited as winter food for the bees and a nuisance to beekeepers.

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