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NEW ZEALAND BEEKEEPER, JULY 2017
Chloe (Laboratory Technician) loads prepared samples onto the Thermo Ultimate 3000 UHPLC for leptosperin analysis. Photo courtesy of Analytica Laboratories.
Average Leptosperin Levels in Different Floral Nectars
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MPI has not included leptosperin in its proposed GREX MPI has been carrying out a science programme over the past few years to come up with a way of defining mānuka honey for international markets. There are a number of resources related to this on the MPI website (www.mpi.govt.nz). MPI has included laboratory testing for five attributes in honey as part of their proposed General Requirements for Export (GREX), with four of these tests being for chemical markers. MPI has not selected leptosperin as one of these markers, and have explained their reasoning for doing so in the documents released in April 2017 that describe the proposed GREX. Reference Kato, Y., Fujinaka, R., Ishisaka, A., Nitta, Y., Kitamoto, N., & Takimoto, Y. (2014). Plausible authentication of mānuka honey and related products by measuring leptosperin with methyl syringate. Journal of Agriculture and Food Chemistry, 62 (27), 6400–6407.
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Kānuka
Pōhutukawa Rewarewa
Tawari
Blue Borage Honey Dew Kāmahi
Mānuka
Figure 2: Concentrations of leptosperin in nectar from different species. The nectar data was generated from research carried out by UMFHA.
Testing honey for leptosperin The UMFHA has licensed the right to test for leptosperin from Professor Kato, and use the test to authenticate mānuka honey produced in New Zealand. UMFHA has given permission for the test to be set up at commercial laboratories in New Zealand and overseas, and the test is available for anyone to use. We see a wide range in the concentration of leptosperin in commercial honey samples. From all samples tested by Analytica Laboratories to date, the average concentration
is about 300 mg/kg, and the highest result was about 1800 mg/kg. Around 80% of samples fall in the range of 0–500 mg/kg. Beekeepers marketing honey to UMFHA members may find it worthwhile testing for leptosperin to improve its value. Some initial work also shows that leptosperin, in conjunction with another mānuka chemical marker, has potential for use for in- field or in-factory screening of samples using a portable device.
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