CHANGES OF LINOLEIC ACID CONCENTRATION DURING HEATING OF SOME PLANT‐ORIGIN OILS WITH POLYPHENOL ADDITION

Abstract

ABSTRACT The present study aimed at evaluating the influence of phenolic compounds (quercetin, caffeic acid, protocatechuic acid) on inhibition of linoleic acid concentration changes in heated plant‐origin fats: corn oil, grape seed oil, peanut oil, rapeseed oil, sesame oil and soybean oil. When comparing the control samples without and those with phenol addition, a significantly positive influence of all applied compounds was observed. The highest values were recorded for peanut oil heated for 120 h with protocatechuic acid addition (0.02 and 0.04%): Ih18:2 = 23.6% and Ih18:2 = 23.4%, respectively. In the case of grape seed oil, linoleic acid concentration in initial sample (“0”) was about 50.0/100 g, and 40.3/100 g after 120 h of heating; that acid levels ranged from about 42.1/100 g (quercetin 0.04%), Ih18:2 = 4.5% to 46.6/100 g (caffeic acid 0.02%), Ih18:2 = 15.7% in samples with antioxidant addition after 120 h of heating.PRACTICAL APPLICATIONSResults achieved in the present study confirm the possibility and efficiency of phenolic compound application (quercetin, caffeic acid and protocatechuic acid) in protecting changes occurring in stored and heated fats. Furthermore, the study confirms the possibility to apply the comparative GC analysis for indirect characterization of efficiency of applied antioxidants in inhibiting unfavorable changes in triacylglycerol fraction of fatty acids in fats.