Fatty Acid Diagnostic Ratios to Screen for Used Oil Adulteration in Refined, Bleached, Deodorised Palm Oil

Abstract

After episodes of gutter oil incidents related to food safety, customers have become wary about the use of oil in food. The goal of this investigation is to determine the oil used by fatty acid diagnostic ratios. Four types of meat (beef, mutton, pork, and fish) and a control set were fried in refined, bleached, deodorised palm oil (RBDPO) for 25 cycles at 180 °C to replicate used oil. A gas chromatography-flame ionisation detector was employed to analyse refined, bleached, deodorised palm oil. The difference between pure, admixed, and used RBDPO was explained by PCA. While used, RBDPO from different frying cycles was indistinguishable. Only one misclassification in the beef and fish groups occurred when the discriminant models distinguished pure RBDPO from used and admixed RBDPOs. In conclusion, diagnostic ratios of oleic acid to palmitic acid and stearic acid and palmitic acid to oleic acid and linoleic acid in pure, admixed, and used RBDPOs were the most important discrimination factors.