Synergistic effects of rosemary, sage, and citric acid on fatty acid retention of palm olein during deep-fat frying

A study to optimize the use of oleoresin rosemary extract, sage extract, an d citric acid in refined, bleached, and deodorized (RBD) palm olein during deep-fat frying of potato chips was performed using response surface method ology. Results showed that the natural antioxidants used in this study reta rded oil deterioration, as evidenced by retention of fatty acid profiles. T he linoleic to palmitic (C18:2/C16:0) ratio was chosen as the parameter for optimizing the use of natural antioxidants in RED palm olein during deep-f at frying. Linoleic (R-2 = 0.946) and palmitic (R-2 = 0.825) acids were fou nd to be the most important dependent variables, giving highest R2 values t o various antioxidant treatments after 25 h of frying. All three antioxidan ts had independent significant (P < 0.05) effects on the C18:2/C16:0 ratio. In fact, significant effects on the C18:2/C16:0 ratio of RBD palm olein we re also given by a second-order form. A combination of 0.076% oleoresin ros emary extract, 0.066% sage extract, and 0.037% citric acid produced the opt imal retention of the essential fatty acid C18:2. In addition, a synergisti c effect among these antioxidants on the fatty acid ratio of RED palm olein was found.