EC Nutrition

The current study examines the physicochemical characteristics of two brands of vegetable oils i.e. soybean and palm olein that are available in Nepal. The oils were employed as a frying medium to fry dried finger chips 2h each day up to 5 days. The oils were assessed using standard techniques for determining the deterioration of used frying oil, such as changes in free fatty acids (FFA), acid value (AV), peroxide value (PV), refractive index (RI), saponification value (SV), iodine value (IV), and total polar compounds (TPC). The free fatty acid ranged between 0.18 ± 0.02 to 0.44 ± 0.01 and the acid value lies between 0.85 mg KOH/g to 0.87 mg KOH/g for the oils used at the end of frying period respectively. The initial IV values of the oils were 131 and 60.58 for SBO and PO, respectively and at the end of the frying period the iodine value decreased to 117 and 49 for the oils respectively, suggesting a notable level of unsaturated bonds in the oil samples. At the end of the frying period the peroxide value of SBO decreased to 3.04 meqO₂/kg and that PO increased to 4.43 meqO₂/kg whereas the TPC level increased to 33.3% and 22.5% for the oils respectively. The FFA, AV value, iodine values, PV and TPC of the final 5 days were statistically significant different (p < 0.05). At the end of the frying period the saponification value increased to 190.81 mg KOH/g and 214.55 mg KOH/g. There is no significant difference entire 5 days (p > 0.05). The refractive index of the oils increased with that of soybean oil going from the initial 1.46738 of the original oil to 1.46915 on frying of the final dried finger chips batch, palm olein‘s refractive index increased from 1.45902 of the original oil to 1.46071 after frying the fifth batch. The elevated refractive index observed in the oil specimens signifies a significant presence of carbon atoms within their fatty acid composition. All these parameters adhered to the Nepal standards for edible oil, indicating the high quality and suitability of the sample oils for consumption up to five days of frying.

 Keywords: Deep Fat Frying; Thermal Degradation; Soybean Oil; Palm Olein

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