Characterization Of Telfairia Pedata (Smith Ex Sims) Hook., Seed Kernel Oil For Nutritional Value And Antioxidant Activity

Abstract

Some plant sources such as the seed kernel of Telfairia pedata contain edible vegetable oil but due to their limited prevalence around the world, little research has been done about them Telfairia pedata (Sm. Ex Sims) Hook seed kernel oil was characterized for its nutritional value as edible vegetable oil. Due to the limited research and availability of this species around the world, it is faced with the danger of extinction. As such, this research not only provides the nutritional information of T.pedata seed kernel oil but also has the potential of contributing to its preservation. Standard laboratory procedures were used for analyzing the oil’s physicochemical parameters while its fatty acid and vitamin E composition were analyzed using gas chromatography mass spectrometer (GC-MS). The oil’s antioxidant activity was determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. The physico-chemical properties of the T. pedata seed kernel oil were determined and the results obtained were as follows: calorific value (MJ.Kg-1) (44.66±0.32; 44.51±0.13; P = 0.5009), density (g/cm3) (0.8439±0.0002; 0.8440±0.0002; P = 0.2524), moisture content (%) (0.0592±0.0140; 0.0517±0.0174; P = 0.5922), refractive index (1.455±0.001; 1.454±0.001; P = 0.2879), specific gravity (0.8752±0.0003; 0.8755±0.0002; P = 0.3039), viscosity (mPa.s) (55.6616±0.0465; 55.6675±0.1586; P = 0.9563), acid value (mg KOH/g) (0.6352±0.0330; 0.6235±0.0326; P = 0.6847), iodine value (g I2/100g) (23.0058±2.2473; 24.2081±0.9563; P = 0.4565), peroxide value (meq O2/Kg) (0.9641±0.2021; 1.2173±0.3124; P = 0.3235) and saponification value (mg KOH/g) (157.3007±2.4640; 157.2805±5.5738; P = 0.9958) for the n-hexane and mechanical pressing extracts, respectively. Monounsaturated, polyunsaturated and saturated fatty acids composition of the oil was found to be 0.13 %, 48.54 % and 51.33 %, respectively in the nhexane and 0.13 %, 45.9 % and 53.97 %, respectively in the mechanical pressing extracts. The individual fatty acids found in T. pedata seed kernel oil included; myristic acid (14:0), palmitoleic acid (16:1), palmitic acid (16:0), margaric acid (17:0), linoleic acid (18:2), stearic acid (18:0), 10,13-octadecadienoic acid (18:2), 18-methylnonadecanoic acid (20:0) and behenic acid (22:0). Micronutrients such as vitamin E and squalene were found to be present in T. pedata seed kernel oil. The n-hexane and the mechanical pressing extracts of the oil were found to have half maximal inhibitory concentration (IC50) values of 18.05 mg/mL and 17.36 mg/mL, respectively, which were significantly lower compared to that of ascorbic acid (IC50 2.406 g/mL), used as the standard. In conclusion, this study found out that T. pedata seed kernel oil has good nutritional value and recommends the oil to be commercialized as an edible vegetable oil.