Relationship of Frying Temperature with Frying Life of Selected Oil Types

Background: Cooking oils used for long periods of frying are subject to oil deterioration. Total polar compounds (TPC) is the general parameter used to quantify oil deterioration wherein the maximum allowable TPC of cooking oil is 25%. The time it takes to reach 25% TPC was defined as the frying life of oil. Objectives: This study was undertaken to determine the effect of oil type and frying temperature on frying life. Methodology: The frying lives of coconut, canola, and palm oil as well as the oils heated at 150°C, 170°C, and 190°C were determined. Spectrophotometric analysis was performed and the TPC values were calculated from absorbance using the equation: y = -2.7865x2 + 23.782x + 1.0309. Results: The mean frying lives were 20.24h, 10.80h, and 13.49h for coconut, canola, and palm oil, respectively. Regardless of oil types, the mean frying lives were 16.23h, 11.93h, and 13.82h at the following frying temperatures namely; 150°C, 170°C, and 190°C, respectively. Two-way ANOVA showed a significant difference in the frying lives of the three oil types and those of the three frying temperatures. Conclusion: Coconut oil had a longer mean frying life than both palm and canola oil. In terms of frying temperature, the longest mean frying life was observed in the oils heated at 150°C, followed by the oils heated at 190°C. There was a significant interaction between oil type and frying temperature observed in the study.