Degree of oxidation depending on the positional distribution of linolenic acid in perilla oil and interesterified products

Interesterified perilla oil (IPO) was produced from rearrangement of fatty acids in perilla oil (PO) using Lipozyme RM IM-catalyzed interesterification. IPO showed a total fatty acid composition similar to PO; however, the positional distributions of ω-3 linolenic acid (ω-3 Ln, ALA) of these two oils were different. Thermal oxidation was performed at 40°C in the dark and oxidative stabilities of PO and IPO were investigated using 1H NMR. After 20 days of oxidation, the concentration of ALA in IPO (47.9±1.3%) was significantly (p<0.05) higher than in PO (40.4±0.6%). IPO (40.6±5.5 mM oil) produced significantly (p<0.05) lower amounts of aldehydes (secondary oxidation products) than PO (61.6±2.0 mM oil). GC and HPLC results showed that the distribution of ALA in the LnLnLn molecule within TAG species was the main reason for improvement in the oxidative stability of IPO.