Glucose oxidase

Definition

Added to nectar by the bees during ripening, glucose oxidase converts glucose into gluconic acid and hydrogen peroxide. The acid is why honey sits at pH 3.5-4.5, and the peroxide is the source of the antibacterial activity that essentially all honey has. The reaction needs water to proceed, so it is largely dormant in concentrated honey and starts when the honey is diluted — which is the mechanism behind peroxide activity in a wound dressing.

Where the word gets used loosely

Peroxide activity is frequently presented as evidence that eating honey fights infection. It does not survive the journey: catalase, an enzyme present in human tissue and blood, destroys hydrogen peroxide, and the activity also degrades with heat and storage. It is a real property of the substance and not a demonstrated effect in a person.

Guide records that discuss this

• Honey chemistry explainedHoney is a supersaturated sugar solution with a small and consequential fraction of everything else. Almost every practical question about honey resolves into a question about that composition.
• The enzymes in honeyHoney is the only common food that arrives carrying the enzymes of the animal that made it. Two of them made the honey, one defends it, and all of them are read in a laboratory as a record of how it has been treated.