Characterization of essential oil from the peel of three citrus species grown in Sikkim Himalaya

The fruit peel of citrus is known to be rich in essential oil. Essential oil content and its characteristics vary amongst the species and climatic factors play a major role. Essential oil, to be suitable for the specific commercial purpose should have basic characteristics. In the present study, extracted oil of selected three citrus species Citrus reticulata, C. maxima and C. jambhiri grown at different altitude of Sikkim Himalaya were characterized. The oil yield was up to 2.4 % in mature fruits and 2.5 % in immature fruits at an altitude of > 1600 m in mandarin orange with significant variations concerning species and altitude. The various analysed oil parameters and their highest values in the study are refractive index (1.49), specific gravity (0.87), free fatty acid (7.83 %), acid value (8.37 %), saponification (163.37 mg KOH / g of oil), iodine value (116 g I2/100 g), peroxide value (36.33 meq O2/ kg), thiocyanogen (77.29 %), ester value (57.63 mg KOH/g), phenol (81.92 mg/g). These parameters also showed variations with altitude and the species. The C. reticulata grown at higher altitude (> 1600 m from MSL) was found to have better essential oils than C. maxima and C. jambhiri with some exceptions. The characteristics highly endorsed the use of these essential oils for food and cosmetic industries. The waste management with simultaneous production of valuable compound is the major perspective sought in the study.