Inhibition of Light-induced Off-flavour Development by Singlet Oxygen Quenchers in Cloudy Apple Juice

Beverage companies sometimes receive reports that cloudy fruit juices have developed a “metallic flavour” when they are exposed to light, which results in consumer complaints. These degradations have been shown to be caused by photooxidation, in which singlet oxygen played an essential role. In the present study, aqueous antioxidants, such as crocin, crocetin, and norbixin, have been investigated. The development of seven off-flavour compounds was monitored in cloudy apple juices from concentrates stored in glass bottles under fluorescent light (3000 lx, 8 °C). It was found that crocin, known to be a singlet oxygen quencher and a food colouring additive, was effective in inhibiting the development of light-induced offflavour.