Quality assessment of frying oils in the formal and informal food preparation sectors

Abstract

The demand for fried foods by the public and the number of people entering the fried food industry in the form of take-aways and fast food outlets both in the formal and informal sectors has increased tremendously. Frying fats and oils are very expensive, used in large quantities and is the most important ingredient used in the preparation of fried foods: Due to the high cost of these frying fats and oils, majority of the formal and informal traders are using the frying fats and oils to its maximum in order to reduce the overall cost. This has resulted in the preparation of poor quality offried foods. Considering all of the above, the aim of the proposed research was :- (a) to determine the quality of the frying fats and oils used by both the formal and informal sectors by performing both physical and chemical analyses and compare these with similar analyses performed on the unused frying fats and oils in order to ascertain the degree of deterioration of the used frying fats and oils (b) to investigate the method of disposal of the used frying fats and oils. (c) to contribute in educating both the consumers and the suppliers of fried foods by bringing the findings of this research to the attention of the Durban Metro Health Department. The used frying fats 'and oils were collected during the frying process by the environment health officer from the Durban Metro Health Department. These samples were placed in a refridgerator to prevent any further deterioration. The used and unused frying fats and oils were analysed for, the Free Fatty Acid and Acid Value contents; the quantitative separation of Monoglycerides, Diglycerides and Triglycerides; the Refractive Index; the Peroxide Values; the concentrations of Polar and Non-polar Compounds; the Viscosity and the identification of the various fatty acid methyl esters present in the samples. The analytical methods used were followed from the American Oil Chemists Society (AOCS) Official Method Handbook. The Free Fatty Acid and Acid Value results showed that twenty-five percent of the samples had a concentration of more than the maximum acceptable limit of 2.5%. It was evident that the types of food fried, the intermittent heating, frying