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HoBee Collecting Honeydew from Oak leafneydew










Honeydew is a classification of honey that refers to honey produced by honeybees collecting nectar that is exuded from another insect such as an aphid or scale insect.

It is quite common in a number of countries and the best known is honeydew from the Black Forest in Germany.

World wide it is referred to variously as "forest honey", "Pine honey", "Fir honey" etc. and may be referred to by the specific species of tree producing the honeydew.


Honeydew label NewBlack Beech with honeydew on the trunk Zealand

Honeydew is one of New Zealand's premium export honeys. It has a history of export to Europe and specifically Germany since the early 1970s. There are several honeydew producing scale insects in New Zealand inhabiting a variety of plants. However most of these are small honeydew sources or intermittent production. The beech forests of the South Island are a different story however. Two species of beech tree inhabited by two species of honeydew insect (the sooty beech scales) produce New Zealand's largest single exported honey crop. The beech trees are Black Beech (Nothofagus solandri) and Red Beech (N. fusca). The two insects are Ultracoelostoma assimile and U. brittini. U. brittini tends to inhabit the trunks and larger branches, while U. assimile is recorded (C.F.Morales) as favouring the upper branches and twigs, thus U.brittini is the insect most likely to be encountered by the casual observer wandering in the beech forests.

The blackHoneydew droplets colour of trees and plants with a honeydew source is due to the growth of a black sooty mould (Capnodium fungus) on the surplus nectar exuding over the plant and sometimes even the ground. Particles of this fungus are typically found in honeydew and are used as a part of the identification as honeydew.

Colour

Beech honeydew is one of our darker honey types with a Pfund Scale average of 87.2mm and a Standard Deviation of 10.5mm (600 records). Colour does depend to some extent on area. There are some areas that do produce darker honeydew. Whether this is due to local conditions or blends of lighter (non honeydew) honeys is uncertain but we can find no correlation between conductivity and colour. Honeydew is generally a slower honey flow than most of the other flower honeys (although there are exceptions of course), and honeybees prefer to store honeys like this closer to the brood nest, typically in darker combs. This can darken the colour of the resultant honey.
Conductivity

New Zealand Beech honeydewis typical of most honeydews in having a high conductivity. This arises from the nature of honedew production. An insect of the Homiptera order of insects (those with sap sucking mouthparts e.g. aphids, scale insects etc.) sucks sap from the host plant and exudes a sweet sticky nectar which is essentially slightly modified sap. This is then collected by honeybees as a nectar source and is "ripened" into honey. This pathway is quite different from that of normal flower honeys. The direct sucking of the sap, the additional insect in the production chain, and the presences of sooty moulds, all add up to an additional mineral content not normally found in flower honeys. This is indirectly measured by the ability of honeydew to conduct electricity. The average conductivity for Beech honeydew is 12.6 mS/cm with a standard deviation of 2.5mS/cm (750 records).Bee collecting honeydew

Sugar Profile

Honeydews are normaly high in Fructose, low in glucose and have higher levels of higher sugars such as maltose . Their tendency to crystallise is also low. Beech honeydew is likewise very slow crystallizing and in fact some beech honeydews never crystallize.

Another feature of New Zealand beech honeydew is the presence of oligosaccharides (complex sugars) in greater levels than average flower honeys.

It has been shown that oligosaccharides are helpful in maintaining and promoting beneficial bacteria in the gut, particularly after treatment with antibiotics.Black beech forest

Moisture Content - Presence of Yeasts

Normally honeydew is below 17% moisture. In the main production area, fermentation is not generally a concern, but the environment is such that large populations of yeast can occur in the honeydew forests. This is due to the presence of large quantities of a food resource (honeydew nectar) and, particularly after rain, wet conditions. At times the forest can smell quite sour with a fermentation smell and wasps can be observed drunk on the tree trunks. Under these conditions, high levels of yeast may occur in honeydew honey that come from this environment, rather than from fermentation of the ripened honey. It is possible that this may be marked against the product as a perceived quality issue, rather than it being a natural occurence.


"Oligosaccharides in New Zealand Honeydew Honey"
K. Astwood, B. Lee, and M. Manley-Harris J. Agric. Food Chem., 46(12), 4958-4962.

Abstract

"A series of oligosaccharides based upon successive addition of glucose (1->4) to the glucopyranosyl residue of sucrose and another series similar to the first but with the final residue linked (1->6) have been isolated from New Zealand honeydew honey and fully characterized. Because the trisaccharide in this series is erlose, it is inferred that the honeydew of the indigenous scale insect, Ultracoelostoma assimile, which lives upon the Southern beech, Nothofagus spp,. is of the erlose type. These oligosaccharides and others have been quantifed by GC and LC in six New Zealand honedew honeys"