Waste to wealth: Industrial raw materials potential of peels of Nigerian sweet orange (Citrus sinensis

Abstract

Orange fruits have been part of human diet for ages due to its nutritional and medicinal values. But consumption of orange fruits generates orange peel wastes that could bring about environmental pollution if not properly handled. Towards recycling of wastes and avoiding littering and waste-related environmental degradation, this study was carried out to explore the components of orange peels with a view to establishing their raw material potentials. Orange peels cut into small bits were subjected to steam distillation process and the extracted essential oil was put through some chemical characterization procedures for purposes of identifying its components. Ultraviolet-visible spectrophotometric scan of the extract, revealed a single prominent peak at a wavelength of 300 nm, as was also the case with paper chromatography which showed one major band separation. Subsequent infrared spectroscopy for structural configuration gave three main identifiable peaks reflecting structural, functional and group/bond positions: C=C, C-H and =C-H at 1640 to 1680 cm^-1, 2850 to 2960 cm^-1 and 3100 cm^-1 bond positions, respectively, and these tallies exactly with those found in the structure of limonene, thus confirming the later (one of the terpenes), as a dominant component of the orange peel among others that were present in small amounts. Limonene is an essential oil with wide application in industrial and domestic domains. Thus, exploring essential oil is an additional way of evaluating the underlying economic value of citrus due to their usefulness as food nutrient and flavor, and their waste peel is a source of essential oil which is useful in cosmetics, pharmaceuticals, and other industrial and domestic applications. Processing of citrus peels into essential oils is a sure way of transforming these wastes with great potential for environmental pollution into a resource with great potential for economic prosperity, and also for securing the public health impacts of safer and healthier environment, likely to be obtained from the indirect waste management option so offered.

Keywords: Industrial raw materials, Citrus sinensis peels.