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Guangzhou Scikoon Industry Ltd. Co.
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2024 Technical Program

Lipid Oxidation and Quality

Session: Effect of Antioxidants During Food Production

New insights into the loss of antioxidant effectiveness of α-tocopherol in the presence of phosphatidylcholine reverse micelles in edible oils

Monday, April 29, 2024
1:55 PM – 2:15 PM EDT
Room: 524c
Abstract: Lipid oxidation in edible oils primarily occurs in reverse micelles (RM) of amphiphilic oil components. While RM's prooxidative impact is acknowledged, its underlying mechanism remains elusive. Previous studies on the influence of phosphatidylcholine (PC) RM on the antioxidant effectiveness (AE) of α-tocopherol and Trolox yielded conflicting results, often using lipid systems with very low antioxidant concentrations. This study aimed to evaluate the impact of PC RM on α-tocopherol AE in stripped sunflower oil (SSO) using an antioxidant concentration typical of sunflower oils (1.16 mmol/kg). The study also explored oil dilution with medium-chain triacylglycerols (MCT). Both Rancimat and oven tests were used to assess AE, with Trolox evaluated for comparison.
Results revealed that increasing PC concentrations (0-1,000 ppm) had no significant impact on α-tocopherol AE, but notable reductions were observed for Trolox in a concentration-dependent manner. However, at a low antioxidant concentration (0.06 mmol/kg) in an SSO and MCT mixture (1:3 w/w), the AE decreased for both antioxidants with PC addition. PC addition to non-stripped oil moderately affected oxidative stability, with slight increases up to 1,000 ppm and a moderate decrease at 5,000 ppm.
In conclusion, the purported prooxidative effects of PC, as observed in studies using model lipid systems with very low antioxidant concentration, appear exaggerated when applied to refined vegetable oils. This suggests a nuanced relationship between PC RM and antioxidant behavior, influenced by factors like antioxidant concentration and oil composition. Understanding these dynamics is crucial for elucidating the complex mechanisms underlying lipid oxidation in edible oils.