Comparison of aroma profiles of essential oils extracted by hydro-distillation from orange peel waste dried by various methods

Abstract

Effects of oven-drying at 45 degrees C (OD45), oven-drying at 55 degrees C (OD55) and microwave-drying at 400 W, 560 W and 700 W (MW400, MW560, MW700) on the content of essential oil extracted using hydro-distillation were studied. To get the highest quality and quantity of essential oil, it is necessary to know the suitable methods for drying. The highest concen-tration of phenolic compounds was determined by UV-spectrophotometryfor OD45, MW400 and MW560, respectively. The highest essential oil yield that was obtained from OD55 samples and the lowest from MW700. Thirty-two compo-nents were identified by gas chromatography-mass spectrometry in essential oil samples, mostly oxygenated monoter-penes and hydrocarbon monoterpenes. The main components were limonene (87.4-90.7 %), p-linalool (2.0-3.7 %), p-pinene (1.7-1.8 %), n-octanal (1.0-1.2 %), alpha-terpineol (0.4-0.7 %) and n-decanal (0.5-0.7 %). The most important changes were remarkable in MW400. It was observed that some components such as 1-nonanol, p-citral, E-2-decanol or o-hydroxybiphenyl, which were negligible in oils obtained from fresh peels, showed a significant increase in oils obtained from MW400.