The hydrophilic nature of ferulic acid limits its applications under lipophilic conditions. This study set out to evaluate the antioxidant efficacy of alkyl ferulates with different chain lengths in soybean oil under frying conditions. Ferulic acid was esterified with four unbranched fatty alcohols (C4:0-C16:0), and tert-butylhydroquinone (TBHQ) served as a standard for comparison. The antioxidant effect of alkyl ferulates increased with the alkyl chain length. The addition of antioxidants could inhibit increases in the levels of p-anisidine, total polar compounds, conjugated dienes, conjugated trienes, oxidized triglyceride monomers, triglyceride dimers, triglyceride oligomers, and glycerol core aldehydes efficiently, and the inhibitory effects of hexadecyl ferulate was the strongest. Moreover, hexadecyl ferulate and TBHQ exhibited better inhibitory effects on the generation of n-alkanals, (E)-2-alkenals, and 4-oxo-alkanals determined by 1H nuclear magnetic resonance than others. Hence, the long-chain alkyl ferulates meet the industrial demands for ideal antioxidants with strong antioxidant capacity at high temperatures.
Keywords: Alkyl ferulates; Antioxidant efficacy; Chain length; Frying.
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