Improving the oxidative stability of flaxseed oil with composite antioxidants comprising gallic acid alkyl ester with appropriate chain length

A gallic acid (GA) alkyl ester exerting the best antioxidant effect in flaxseed oil was identified from ten GA alkyl esters with various chain lengths, which was used in combination with other antioxidants including antioxidant of bamboo leaves, ascorbyl palmitate, butylated hydroxytoluene, phytic acid, phospholipid, rosemary extract, tocopherol, tea polyphenols, and tea polyphenol palmitate (TPP) to improve oxidative stability of flaxseed oil. Rancimat induction period, peroxide value, thiobarbituric acid-reactive substances, and electron paramagnetic resonance assays indicate that myristyl gallate (GA-C14) was the best GA ester. The flaxseed oil containing GA-C14 and TPP demonstrated the best oxidative stability among all the composite antioxidants. Through optimizing the mixture ratio, the flaxseed oil containing 34.4 mg/kg GA-C14 and 480 mg/kg TPP showed the best oxidative stability. Its shelf life was predicted by an accelerated shelf life testing using the Arrhenius model, which was prolonged 4.83-fold compared to the control sample under 25 °C.