Effective strategies for reduction of oil content in deep-fat fried foods: A review

As demands for fried foods are increased by consumers, so is its health concern. Food quality and safety specialists have been making efforts to provide healthy and nutritious foods through optimization of frying processes and products. Studies have revealed that three techniques could be used to reduce the amount of oil in fried foods, namely, modification of product surface, modification of frying technique and modification of frying medium. This review summarizes up-to-date findings regarding the related works of literature undertaken in order to reduce oil content in fried foods. It emphasizes the importance of modifying product surface and frying technique in reducing oil uptake during deep-fat frying. Owing to the fact that frying is majorly a surface phenomenon, modification of product surface has proven to be the most effective procedure in reducing oil uptake. However, more studies are needed in the application of the other two techniques especially modifying the oil medium. Coating has been used as one of the techniques to modify product surface. From the literature reviewed, soy protein isolate, methylcellulose, whey protein isolate and wheat gluten protein isolate showed to be the best materials for coating, depending on the substrate which can reduce oil uptake by 35–40%. Little work has been done on the application of hydrocolloids as pre-dusting agents, although the technique has shown to be effective in enhancing oil reduction in deep-fried foods. Studies have also shown that bulk of oil in fried foods are absorbed during cooling (post-frying) than during frying. Therefore, more research is needed on post-treatment of fried foods to reduce oil content.