Influence of various parameters on the browning of potassium sorbate in the presence of amines.

Potassium sorbate can undergo oxidation to form carbonyl moieties and cause browning. This investigation studied the fate of the compounds produced by auto-oxidation of potassium sorbate and measured the browning in the presence of amines. Experimental plans in which four factors were combined (temperature, oxygen, amine and light) led to the observation that the interaction between oxygen and high temperature (75 degrees C) favoured browning, independently of the presence of amine. At 4 degrees C, the amine seemed to cause a decrease in the proportion of carbonyl-containing compounds which would appear to participate in carbonyl-amine reactions. At 75 degrees C, the amine forms adducts with the potassium sorbate. In parallel, high temperature favours auto-oxidation reactions that produce carbonyls. GC/MS and NMR analysis of the reaction products of potassium sorbate/amine mixtures led to the identification of cyclic products.