Studies on Honey Inhibine. 4. Destruction of the Peroxide Accumulation System by Light

SUMMARY Conflicting reports on the sensitivity of honey inhibine (accumulated hydrogen peroxide) to light are resolved by demonstration of great variability in the effect of light on the peroxide accumulation value of different honeys. Destruction of the glucose oxidase in honey by photo‐oxidation has been observed. This enzyme, responsible for peroxide production in diluted honey, is destroyed in either full‐density or diluted honey by visible radiation, with the 425‐525 mμ region most effective. General laboratory illumination, particularly fluorescent‐tube lighting, is highly destructive to inhibine in a sensitive full‐density honey. The liability of the inhibine of a honey sample to photo‐destruction depends on the presence of a heat‐ and light‐stable, non‐volatile sensitizing material; photo‐oxidation is greatest at pH 3 and negligible at pH 6‐7. Immediate adjustment of the pH of honey samples prepared for bacteriological inhibine assay is therefore essential. Inhibine content of honey is not recommended as a quality factor, because of wide variation in light and heat susceptibility and in distribution according to floral source.