Honey industry: researchers identify source of Unique Mānuka Factor

University of Waikato researchers have uncovered new insights into how mānuka flowers make nectar and the source of the Unique Mānuka Factor – which could contribute to the high-value New Zealand mānuka honey industry.

The research, published in the international scientific journal New Phytologist, was led by Associate Professor Mike Clearwater, a plant physiologist from Te Aka Mātuatua – School of Science at the University of Waikato.

The research investigated why the nectar producing parts of mānuka flowers, known as nectaries, produce the unique ingredients found in the honey. Nectaries are common in many flowering plants, but only mānuka and a small number of related species produce nectar with the active ingredient found in mānuka honey.

The researchers first noticed that in mānuka (Leptospermum scoparium) the nectaries are green, unlike the colourless nectaries of other flowers. They then showed for the first time that nectary photosynthesis – the plant’s process of using sunlight, water and carbon dioxide to create oxygen and sugar – could contribute to nectar production. This contrasts with many other flowers that produce their nectar sugars entirely within their leaves. Continue reading

Proof is in the proteins: new way to validate mānuka honey

Scientists at the University of Auckland and Comvita Ltd have developed a new way to analyse honey by measuring the levels of proteins from mānuka nectar.

The team found 12 potential molecules which are all unique to the mānuka plant. They say this strategy could be used to authenticate honey products more easily and accurately.

The mass spectrometry analysis was performed by the Mass Spectrometry Centre, Auckland Analytical Science Services, School of Biological Sciences, University of Auckland, and funded by Comvita NZ Ltd.

A brief report on the findings has been published by Scimex.

The paper to which Scimex readers are steered sets out four highlights:

•   Identification of unique peptides in NZ mānuka honey & L. scoparium nectar.

•   L. scoparium nectar peptides were not present in other plant species nectar.

•  Bottom-up proteomic approach using nano-liquid chromatography separation with HRMS.

•  Proteins were identified based on a predicted mānuka proteome and database searches.

The Abstract says:

Proteomics is an emerging tool in food authentication that has not been optimised for honey analysis. In this study, we present a qualitative proteomic analysis of New Zealand mānuka (Leptospermum scoparium) honey.

A total of 50 bee-derived proteins were identified in the honey, the most predominant being major royal jelly proteins (MRJPs). We also demonstrate for the first time the presence of unique nectar-derived proteins in mānuka honey.

A total of 17 mānuka plant proteins were identified, a-third of which were putative pathogenesis-related proteins. Two proteins involved in drought tolerance were also identified.

Twelve candidate peptides were selected as potential authentication markers based on their uniqueness to mānuka honey. Nectar analyses confirmed the origin and specificity of these peptides to L. scoparium nectar, thus presenting peptide profiling as a viable and novel approach for mānuka honey authentication.

Raw data are available via ProteomeXchange with identifier PXD021730.

Link to research (DOI): 10.1016/j.foodchem.2020.128442

Source:  Scimex