Effects of irradiation in combination with waxing on the essential oils in orange peel

The study evaluated the effects of waxing, irradiation dose and post-irradiation storage time on the essential oils in orange peel. Mature oranges (Maroc late) waxed or unwaxed were treated with 1 or 2 kGy radiation and stored for 9 weeks at 20 °C and 40-50% RH. Essential oils from the peel were extracted and analysed by GC. Results showed that D-limonene was significantly lower in waxed oranges; levels in samples treated with 2 kGy were higher than those in non-irradiated or treated with 1 kGy. Linalool, methyl anthranilate and 3,7-dimethyl-2,6-octadienal decreased as the dose increased. Levels of linalool increased with storage time but D-limonene was unaffected. These results may aid in guaranteeing the quality of orange essential oils during storage time.