Extraction and Characterization of Essential Oils Using Nigeria Sweet Orange and Lemon Peels

Due to the abundance of orange and lemon peels dumped as waste in Nigeria, after their juices have been consumed by the populace, there is a need to research if these peels can serve other purposes. Hence this work studies the extraction and characterization of essential oil from Nigerian sweet orange and lemon peels, in order to determine their physicochemical properties. This work involved the application of cold press maceration and soxhlet extraction methods to obtain essential oils from the peels of Nigerian sweet oranges and lemons. 800g and 1000g of lemon and orange peels were the weight of samples used respectively, and the oils extracted were subjected to chemical analysis using GC-MS and FTIR characterization to identify key bioactive compounds. Percentage yields of 13.30, 12.00 and 5.70, 6.50 % (V/W) of essential oils of lemon and orange peels were obtained by the maceration and soxhlet extraction method respectively, and the yield of lemon peel oil increased with increasing extraction time. Physicochemical analysis of the oils were conducted using standard procedures to obtain pH (5.00 and 4.70), density ( 0.81 and 0.86g/cm3 ), specific gravity (0.80 and 0.85), acid value (12.90 and 10.00mg/l), iodine value (130.50 and 147,00 g/100g), saponification value (180.90 and 194.00mgKOH/g) and peroxide value ( 2.90 and 2.70meq/kg). The chromatographic analysis resulted in the identification of 28 compounds representing a total of 99.41%. The spectrum presented characteristic bands at 1600-1680 cm-1 corresponding to C=C; the signals appearing between 3100-3000 cm-1 and 3150-3050 cm-1 are caused by the asymmetrical and symmetrical stretching vibrations of C–H groups. The best type of extraction method was soxhlet using n-hexane solvent at extraction time of 10 hours. This work concluded that citrus peels are a viable source of high-quality essential oils, with great potentials for therapeutic, cosmetics and industrial applications.This work not only demonstrates the potential of citrus peels waste in essential oil production to combat its massive waste disposals in the environment, it also lay a good foundation for further research into optimizing extraction techniques and expanding the applications of these oils.