Effect of frying oil stability over repeated reuse cycles on the quality and safety of deep-fried Nile tilapia fish (Oreochromis niloticus): a response surface modeling approach

Fresh water fish is considered a source of good quality proteins and essential fats. Frying is among widely used fish preparation techniques globally. Deep-frying oil quality with repeated uses, has been a concern. This research investigated the influence of frying oil stability (expressed as levels of peroxide values (0.2, 1.2 meq/kg) and free fatty acids (0.05, 0.13% palmitic acid)) over repeated uses (1,6 cycles) on the oxidative stability and essential nutrients of fried fish using a response surface approach, with the objectives of generating information relevant for the improvement of community health outcomes, with a special focus of this particular research was on trends, but not optimization. The frying oil and fried fish quality were adequately explained by response surface model and supported by principal component analysis. The result showed that the oxidative stability of both the frying oil and fried fish were deteriorating over the reuse cycles of the frying oil (with increasing trends of unhealthy fats, saturated and trans) corresponding to decreasing trends in the healthy fat components and vitamin A). It was also indicated that the essential fats (omega 3, omega 6, cis, vitamin A), were decreased while the risky fats (saturated, trans) were increased along with the frying cycles. The result revealed the urgent need for regulating frying oil and fried food qualities, particularly in developing countries.