Authentication of Mānuka Honey

07/12/2020

Authentication_of_Manuka_Honey

For honey to be legally labelled as ‘Mānuka honey’, it must be predominantly collected from the nectar of Mānuka (Leptospermum scoparium) flowers1. Manuka (Leptospermum scoparium) honey contains unique and beneficial compounds, laboratory testing for these compounds is used to determine the purity and potency of manuka honey.

In New Zealand the Ministry for Primary Industries (MPI) enforces a Scientific Regulatory Definition for exported manuka honey based on chemical fingerprinting and pollen DNA marker analysis2. The definition requires minimum amounts of four specific phenolic compounds to be present in the honey:

  • 2-methoxybenzoic acid
  • 2’-methoxyacetophenone
  • 3-phenyllactic acid
  • 4-hydroxyphenyllactic acid
  • along with a manuka pollen DNA marker.

These compounds are produced naturally in the nectar of manuka flowers and therefore naturally occur in manuka honey3. At Comvita, we ensure that both our domestic and export Mānuka honey meets MPI standards. This means that, wherever they buy our product, our consumers can be confident that they are buying genuine Mānuka honey from New Zealand.

In addition to the compounds specified by the MPI definition, Comvita scientists, and others, have pioneered the discovery of other compounds unique to manuka honey including dihydroxyacetone (DHA), methylglyoxal (MGO), leptosperin and Lepteridine™ 3,6,7-Trimethyllumazine which are used to authenticate the purity and potency of manuka honey7,8,9,10,11,12.

Characteristic Compounds Found in Mānuka Honey

Methylglyoxal (MGO)

is a compound which is principally responsible for Mānuka honey's unique non-peroxide antibacterial activity that is not present in other honey types.

There have been cases of adulteration where synthetically made MGO has been added into honey to make ‘fake’ Mānuka honey. Therefore, measuring MGO alone is not a guarantee of the purity and quality of Mānuka honey4,5,6.

Methylglyoxal (MGO) compound

Dihydroxyacetone (DHA)

is a natural plant compound found in the nectar of Mānuka flowers. DHA converts to MGO over time in Mānuka honey as it matures5.

Dihydroxyacetone (DHA) compound

Leptosperin

is a unique natural plant compound found only in Mānuka honey. It is extremely difficult to make synthetically and is not commercially available. As this compound cannot be artificially added to Mānuka honey it is an excellent marker for authenticity7,8,9,10,11,12.

Leptosperin compound

Lepteridine™ 3,6,7-Trimethyllumazine

is a unique natural plant compound found only in Mānuka honey and was discovered by Comvita Scientists. It is extremely difficult to make synthetically and is not commercially available. As this compound cannot be artificially added to Mānuka honey it is an excellent marker for authenticity11.

Comvita is the only company that tests for Lepteridine™ 3,6,7-Trimethyllumazine levels in Mānuka honey.

Lepteridine™ 3,6,7-Trimethyllumazine compound

References:

1. Codex Alimentarius Comission. Codex alimetntarius: fats, oils and related products. FAO, 2001.

2. Ministry for Primary Industries. Mānuka honey science definition. Retrieved from https://www.mpi.govt.nz/growing-and-harvesting/honey-and-bees/manuka-honey/ . (2017).

3. Smallfield. B. M., Joyce, N. I., & van Klink, J. W. Developmental and compositional changes in Leptospermum scoparium nectar and their relevance to manuka honey bioactives and markers. 2018. New Zealand Journal of Botany, 56(2), 183-197.

4. Mavric E, Wittmann S, Barth G, Henle T. Identification and quantification of methylglyoxal as the dominant antibacterial constituent of Manuka (Leptospermum scoparium) honeys from New Zealand. Molecular nutrition & food research. 2008, Vol. 52, 4, pp. 483-489.

5. Adams CJ, Manley-Harris M, Molan PC. The origin of methylglyoxyl in New Zealand manuka (Leptospermum scoparium) honey. Carbohydr Res. May 26, 2009, Vol. 344, 8, pp. 1050-1053.

6. Adams CJ, Boult CH, Deadman BJ, Farr JM, Grainger MN, Manley-Harris M, Snow MJ. Isolation by HPLC and characterisation of the bioactive fraction of New Zealand manuka (Leptospermum scoparium) honey. Carbohydr Res. Mar 17, 2008, Vol. 343, 4, pp. 651-659.

7. Bong J, Prijic G, Braggins TJ, Schlothauer RC, Stephens JM, Loomes KM. Leptosperin is a distinct and detectable fluorophore in Leptospermum honeys. Food chem. 2017, Vol. 214, pp. 102-109.

8. Bong J, Loomes KM, Lin B, Stephens JM. New approach: chemical and fluorescence profiling of NZ honeys. Food Chemistry. Nov 30, 2018, Vol. 267, pp. 335-67.

9. Kato Y, Fujinaka R, Ishisaka A, Nitto Y, Kitamoto N, Takimoto Y. Plausible authentication of manuka honey and related products by measuring leptosperin with methyl syringate. J Agric Food Chem. Jul 9, 2014, Vol. 62, 27, pp. 6400-6407.

10. Lin B, Loomes KM, Prijic G, Schlothauer R, Stephens JM. Lepteridine as a unique fluorescent marker for the authentication of manuka honey. Food Chem. Jun 15, 2017, 225, pp. 175-180.

11. Daniels BJ, Prijic G, Meidinger S, Loomes KM, Stephens JM, Schlothauer RC, Furkert DB, Brimble MA. Isolation, structural elucidation, and synthesis of lepteridine from manuka (Leptospermum scoparium) honey. J Agric Food Chem. Jun 22, 2016, Vol. 64, 24, pp. 5079-5084.

12. Stephens JM, Loomes KM, Braggines TJ, Bong J, Lin B, Prijic G,. Fluorescence: A Novel Method for Determining Manuka Honey Floral Purity. Honey Analysis. Mar 15, 2017, 95.