Process Optimization for Minimizing Residual Free Fatty Acid Levels in Fried Mustard Oil: Isotherm and Kinetics Studies

Abstract

AbstractAdsorbents have been used as filtration aids for the effective regeneration of repeatedly used frying oils. In this study, mustard oil used in the continuous frying of potato chips was treated with bentonite at different concentration levels. Response surface methodologies with central composite rotatable design was employed to optimize the influence of process parameters (contact time, heating time and adsorbent concentration) on residual free fatty acid (FFA) levels. The optimized values of contact time, heating time and adsorbent concentration were found as 10 h, 10 h and 0.4 g/L, respectively, for keeping the residual FFA levels below the allowable limit. Kinetics studies revealed that adsorption of FFA follow pseudo second order with good agreement between calculated and experimental data. The Langmuir adsorption is appropriate for correlation of equilibrium data. Treatment of fried mustard oil with bentonite may improve the quality characteristics of fried foods and extend the frying life of oil.Practical ApplicationsDeep fat frying is a complex thermal process producing fried foods with distinct color, flavor and texture. The overuse of oil in deep fat frying results in the formation of several compounds which are harmful to human health. So the repeated use of oil should be prevented in order to overcome these issues. In the present work, we investigated the use of bentonite to reduce the FFA levels in the deep fat fried mustard oil. The effect of heating time, contact time and adsorbent concentration on the adsorption process has been optimized with the application of response surface methodology. By this treatment the health aspects of used frying oils may be improved and the disposal levels of fried mustard oil may be reduced.