Performance of palm olein in repeated deep frying and controlled heating processes

The stability of refined, bleached and deodorised (RBD) palm olein was studied under both repeated frying and controlled heating conditions. Two different frying foods i.e. chicken nuggets and French fries were used to evaluate the oil performance under various frying conditions. Thermo-oxidative alterations were measured through various physical and chemical parameters. Total polar compounds (TPC), polymeric triglycerides (PIG), blueness (b* value), chroma (C* value), refractive index and viscosity increased linearly with the number of frying/heating cycles. Palmitic acid content increased and linoleic acid content decreased linearly with the number of frying cycles. No significant changes in oleic acid were detected. Thermo-oxidative reactions induced under the heating conditions were found to be faster as compared to those under the frying conditions. The PTG formed at the end of heating cycles (16.42%) were substantially higher as compared to those formed at the end of frying French fries (9.72%) and chicken nuggets (5.34%). (C) 2009 Elsevier Ltd. All rights reserved.