Generation of oxidative species from ultraviolet light induced photolysis of fructose

Fructose has shown significant reactivity during ultraviolet light (UV, 254 nm) processing of fruit juices that can adversely affect product quality. The present study demonstrates that this reactivity of fructose is due to the oxidative nature of products formed from UV induced photolysis of fructose. This was accomplished using fluorescein, a fluorescent dye that loses fluorescence intensity upon reaction with oxidative species. Fructose caused a concentration dependent decay of fluorescence from fluorescein only in presence of UV, indicating oxidative nature of photolysis products of fructose. The transient oxidative species including free radicals and not one of the final photolysis products, furan, were responsible for fluorescence decay. Addition of an antioxidant and removal of oxygen from solution lowered the rate of fluorescence decay, suggesting strategies that can be employed to lower the deleterious effects of fructose on products. The understanding developed can be used to optimise UV processing of juices.