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Peter Loring Borst <[log in to unmask]>
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Informed Discussion of Beekeeping Issues and Bee Biology <[log in to unmask]>
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Mon, 13 Sep 2010 12:02:00 -0400
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Then we have the issue of false positives, which can break deals and reputations



> Carbon isotope analyses (δ13C) of some New Zealand Manuka honeys show that they often fail the internationally recognised Association of Official Analytical Chemists sugar test (AOAC method 998.12) which detects added C4 sugar, although these honeys are from unadulterated sources. Failure of these high value products is detrimental to the New Zealand honey industry, not only in lost export revenue, but also in brand and market reputation damage. The standard AOAC test compares the carbon isotope value of the whole honey and corresponding protein isolated from the same honey. Differences between whole honey and protein δ13C values should not be greater than +1.0‰, as it indicates the possibility of adulteration with syrups or sugars from C4 plants such as high fructose corn syrup or cane sugar.



> We have determined that during the standard AOAC method, pollen and other insoluble components are isolated with the flocculated protein. These non-protein components have isotope values which are considerably different from those of the pure protein, and can shift the apparent δ13C value of protein further away from the δ13C value of the whole honey, giving a false positive result for added C4 sugar. To eliminate a false positive C4 sugar test for Manuka honey, prior removal of pollen and other insoluble material from the honey is necessary to ensure that only the pure protein is isolated. This will enable a true comparison between whole honey and protein δ13C isotopes. Furthermore, we strongly suggest this modification to the AOAC method be universally adopted for all honey C4 sugar tests.



Eliminating false positive C4 sugar tests on New Zealand Manuka honey

Rapid Communications in Mass Spectrometry

Volume 24, Issue 16, pages 2370–2374, 30 August 2010



Peter Loring Borst

Ithaca NY USA

peterloringborst.com

















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