Sulphur dioxide in foods:– chemical interactions

SUMMARy Sulphur dioxide is a versatile food additive which has extensive chemical reactivity. The components of food, and biological systems in general, which may react with this additive include proteins, coenzymes and enzyme cofactors and prosthetic groups. Enzymic browning in cut fruits and vegetables is inhibited by reaction of sulphite ion with quinone intermediates. Inhibition ofnonenzymic browning in a wide range of foods, including beverages and dehydrated products, takes place by inactivation of carbonyl intermediates. Sulphite ion is detoxified in man by sulphite oxidase whilst one of the known products of reaction between hydrogen sulphite ion and intermediates in nonenzymic browning is metabolically inert.