Quality control of refined oils mixed with palm oil during repeated deep‐frying using FT‐NIRS, GC, HPLC, and multivariate analysis

Abstract

Frying performance of blends of a monounsaturated oil like refined olive oil (ROO) or a polyunsaturated oil such as refined soybean oil (RSO) with a refined oil rich in saturated fatty acids like refined palm oil (RPO) was investigated by assessing their chemical changes during 50 successive deep‐frying sessions of potato fries at 180°C. The blends were prepared in the volume ratio of 80:20 (ROO/RPO and RSO/RPO). Indeed, the chemical properties of the frying oil blends were significantly (p < 0.05) influenced by type and concentration of oil compounds. The ROO/RPO blend exhibited the highest chemical stability during the frying process, and the RSO/RPO blend showed the lowest stability. In fact, 25% of total polar compounds were exceeded after 40 successive deep‐frying sessions for the ROO/RPO blend, whereas after 30 sessions for the RSO/RPO blend. Finally, ROO/RPO blend revealed better frying performance than that of RSO/RPO, as confirmed by both statistical analyses such as principal component analysis (PCA) and repeated measures analysis of variance (ANOVA).Practical applications: The use of the newly proposed product which is characterized by a strong thermo‐oxidative stability during repeated deep‐frying like refined olive oil (ROO)/refined palm oil (RPO) blend is a promising possibility. It is hoped that the data obtained from this research study may help food manufacturers to decide on the suitable oils for their frying operations.Application of FT‐NIRS, GC, HPLC, and multivariate analysis proved that the newly proposed product ROO/RPO blend characterized by a strong thermo‐oxidative stability is a suitable oil for frying operations.