UMF Honey Association’s Grading System
(The Purity and Quality of Manuka)
The Consumer is demanding assurances of quality and purity when contemplating purchasing New Zealand Manuka honey. Accordingly the UMFHA has been pursuing best science to undertake chemical profiling, as utilised with other high value consumer favourites, to effectively fingerprint honey by floral type and quality attributes. Distinctive markers are identified, which are characteristic of the floral type, abundant, stable, and not easily able to be synthesised and hence potentially adulterated.
Manuka honey is complex, being made up of a multitude of components.
The Manuka ID Project has identified a number of potentially worthwhile chemical markers, and has focused on 4 of these to develop scientifically-based classification criteria for Manuka honey that will give confidence to consumers who want to purchase quality authentic Manuka honey. One of these 4 markers is Leptosperin.
We know that some of these components are characteristic of the Manuka floral type, and some are not found in any other monofloral honey. One key component is Leptosperin. Professor Yoji Kato of Hyogo University was the first to affirm this component and its value for identification of Manuka honey.
Some key facts about Leptosperin:
1. It is characteristic of Manuka and some other Leptospermum species
As yet this compound has not been found in nectar of any New Zealand flower type other than Manuka (Leptospermum scoparium). Its unique presence in Manuka flower nectar proves that its presence in honey can only be derived from Manuka plants. It has been found in some Australian Leptospermum species honey, but these are easily differentiated from New Zealand Manuka using melissopalynology or trace mineral analysis. Currently, this is not an issue as it is illegal to import any overseas honey.
2. It is abundant in Manuka
The comparatively high levels of Leptosperin found in Manuka make it straightforward to test for. This test can be integrated by laboratories into their existing testing regimes. For example, the existing 3-in-1 test for DHA, methylglyoxal, and HMF could be expanded to a ‘4-in-1’ test including Leptosperin.
3. It is relatively stable
In stability trials samples were incubated at 21, 27, and 34 degrees Celsius, respectively. Leptosperin shows little degradation over time, particularly when compared to methylglyoxal which shows a dramatic increase (see graphs below).
4. It is difficult to synthesise and thus less likely to be used in any adulteration
Other characteristic compounds in Manuka honey have been examined but ruled out from use as markers if they are easy to synthesise in commercial quantities such as may be used for large-scale adulteration.
5. It can be readily used along with other targeted markers
We will not be relying on one marker for the determination of ‘Manukaness’.
6. There are a number of respected peer-reviewed scientific publications on Leptosperin, from Professor Kato and Professor Karl Speer.
Relevant published papers:
Kato Y, Fujinaka R, Ishisaka A, Nitta Y, Kitamoto N, Takimoto Y. (2014). Plausible authentication of manuka honey and related products by measuring leptosperin with methyl syringate. J Agric Food Chem., 62(27), 6400-7. doi: 10.1021/jf501475h.
Kato Y, Araki Y, Juri M, Fujinaka R, Ishisaka A, Kitamoto N, Nitta Y, Niwa T, Takimoto Y. (2014). Immunochemical authentication of manuka honey using a monoclonal antibody specific to a glycoside of methyl syringate. J Agric Food Chem., 62(44), 10672-8. doi: 10.1021/jf503464a
Beitlich, N., Koelling-Speer, I., Oelschlaegel, S., and Speer, K. (2014). Differentiation of Manuka Honey from Kanuka Honey and from Jelly Bush Honey using HS-SPME-GC/MS and UHPLC-PDA-MS/MS. J Agric Food Chem, 62(27), 6435-6444. doi: 1021/jf501818f
7. Preliminary research indicates that Leptosperin may be bioactive
Work being done on this by Dr Peter Brooks and Daniel Meloncelli of the University of the Sunshine Coast.
The UMFHA Executive has signed a contract with Healthcare Systems Japan Ltd for the sole rights to the patent which protects the application of Leptosperin to identify Manuka honey.