Inhibition of citral degradation by oil-in-water nanoemulsions combined with antioxidants

The aim of the present study was to investigate the effects of oil-in-water (O/W) nanoemulsions combined with six different natural antioxidants on the stability of citral. Acidic emulsions (lecithin-stabilized palm kernel lipid in pH 3 buffer) containing 1000 ppm citral and 1000 ppm antioxidants (black tea extract, ascorbic acid, naringenin, tangeretin, β-carotene, and tanshinone) were stored at 25 and 50 °C, respectively. The emulsions with and without antioxidants were analyzed by solid phase microextraction gas chromatography (SPME-GC) to monitor the degradation process of citral and the formation of different off-flavor compounds, such as α,p-dimethylstyrene and p-methylacetophenone. The results suggested that encapsulation of citral in emulsions and the addition of the appropriate antioxidants (β-carotene, tanshinone, and black tea extract) could greatly enhance citral's chemical stability during storage.