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Performance of soybean oil and palm olein during the deep-fat frying of 45 batches of frozen prefried french fries was studied. The peroxide index increased faster for the soybean oil, with a final value of 12 meq/kg. Free fatty acids increased with the number of fried batches and were higher in the palm olein. Total color change was more noticeable in soybean oil in comparison to the palm olein. Viscosity, total polar compounds, and p-anisidine values increased and were higher in soybean oil. A reduction of unsaturated fatty acids was observed from the chromatography analysis. Elaidic and linoelaidic acids, which are trans-fatty acids, had higher concentrations in degraded soybean oil. Palm olein was more stable than soybean oil under the conditions of this study and produced french fries with a lower oil content.

Sensory analysis is a valuable tool used to determine the effect of a formulation or process on the perception of a product. In this study, triangle tests were performed to determine differences between fried foods cooked in fresh palm olein and a fresh blend of canola oil and palm olein (50/50) and between food products fried in fresh oil and those fried in used oil. Freshness did not cause a significant difference between french fries and chicken nuggets, as evaluated by 72 nontrained judges (p > 0.05). However, the kind of oil had an effect on the sensory perception of the fried foods, in particular the flavor and texture of both products (p < 0.05).

Summary Stability of palm olein (PO) and a blend 50% palm olein/50% canola oil (POC) during deep-fat frying at 180 °C of French fries (FF) or chicken nuggets (CN) was studied through the determination of physical and chemical parameters in the fresh and used oils. Degradation at the end of the study resulted in total polar compounds of 12–13.5% for PO and 11.5–14.5% for POC and viscosity of 65–123.3 cP for PO and 63–72.8 cP for POC. Lower peroxide values (5.33–6.32) were obtained for the blend (PO had 5.21–8.55). Food type affected colour parameters and p-anisidine value of the oils. For CN, the lowest fat content and higher hardness were obtained when they were fried in PO. CN caused a faster deterioration in the oils, in comparison with FF, especially in POC. Gas chromatography allowed to observe differences in fatty acids composition for both used oils.