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NEW ZEALAND BEEKEEPER, DECEMBER 2016
or trees relative to each other and can estimate if the site will produce high-grade mānuka honey. At right: Figure 2. Results for 10 trees analysed from one site. Samples were analysed separately. In addition, equal portions were added together to form one composite sample that was below the detection limit of the method. References Adams, C. J., Manley-Harris, M., & Molan, P. C. (2009). The origin of methylglyoxal in New Zealand mānuka (Leptospermum scoparium) honey. Carbohydrate Research, 344 (8), 1050– 1053. Kauri Park. (2016). Manuka provenances [Pamphlet]. Northland, New Zealand. KEY POINTS • Analysis of the nectar of mānuka trees is a useful tool for beekeepers, landowners and nurseries to identify trees that will contribute to higher-grade mānuka honey. • Dihydroxyacetone (DHA) and Leptosperin are present in mānuka nectar. The concentration of these compounds differs between varieties of mānuka. • DHA is converted to methylglyoxal (MG), which is responsible for the non-peroxide activity (NPA) in mānuka honey. • Samples are collected by combining the nectar from 10 flowers on one tree.
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honey with nectar from many mānuka and non-mānuka flowers. • Northland varieties of mānuka flower early in the season; flowering occurs later in the season the further south the trees are. If Northland varieties are planted too far south, they will flower before the weather is warm enough for nectar to be produced. • When choosing good trees, floral density, nectar production and resilience to disease are other factors that should also be considered.
Samples may be 100% nectar or a form of dilution (either 0.1 mL or 1.5 mL liquid to dissolve the nectar). • Samples must be chilled so that fermentation of the sugar does not occur. • Concentrations of DHA and Leptosperin are normalised to the sugar content, which gives an approximation of the mg/kg that would be found in a honey solely created from the one tree. • The reported result for the nectar is at least double the concentration that will be found in a honey, due to bees diluting the
These bees were behaving perfectly, showing off their clever handiwork on their brood frame. Photo: Donna and Jeff Montrose, Warkworth.
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