Differentials in chips and reused oil quality of fried plantain

Background: Plantain chips are popular snack enjoyed by all ages in Nigeria; however, repeated use of oil for frying is a common practice among Nigerians.Objective: This study evaluated the oxidative stability of groundnut oil used repeatedly for frying the plantain chips and physicochemical characteristics of the fried chips.Methods: Plantain fingers were peeled, sliced into chips (2 mm thick), soaked (3 min) in 5% salt solution, drained out (5 min) and fried in groundnut oil (2.5 litres) within 12 – 15 minutes on the first day. On the 3rd, 5th, 7th and 9th days of the experiment, fresh plantain chips were similarly prepared and fried with the same groundnut oil. The groundnut oil was analysed for oxidative stability while chips were analysed for physicochemical characteristics.Results: Repeated use of the same oil in subsequent frying significantly (p < 0.05) decreased quality of both the oil and chips. The chips appearance darkened; and its protein and ash contents decreased from 3.59% and 9.48% in the 1st day chips; and to 3.11% and 8.84% in the 9th day chips respectively. Calcium (Mg/100g) and β-carotene contents (Mg/100g) respectively decreased from 10.37 and 1077.67 in the 1st day chips to 9.59 and 257.12 in the 9th day chips. Physicochemical parameters of the oil deteriorated. Iodine value decreased while free fatty acid, peroxide value and thiobarbituric acid number increased.Conclusion: The oil darkened in colour with increasing rancid characteristics as it was being used repeatedly for frying fresh plantain chips while this decreased physicochemical characteristic of the fried chips The same oil, particularly groundnut oil, should not be used over time for frying chips in order to protect consumers from health-related issues that might arise from consuming such oil and chips.