Stabilization of canola oil with flavonoids

The antioxidant activity of a number of flavonoids in refined-bleached (RB) canola (double-zero rapeseed) oil is compared with that of commonly used synthetic antioxidants, namely, butylated hydroxyanisole, BHA, and butylated hydroxytoluene, BHT. The study was carried out over a thirteen-day period at 65°C and progression of oxidation was followed by monitoring weight gain and peroxide and 2-thiobarbituric acid (TBA) values. Among the flavonoids tested, myricetin, (−)epicatechin, naringin, rutin, morin, and quercetin were superior to BHA and BHT in inhibiting oil oxidation. The addition of myricetin, the most active flavonoid tested, delayed the induction period of lipid oxidation by up to fifteen days and also inhibited the formation of oxidation products by 69% during this period. Natural flavonoids may therefore have potential application for the stabilization of canola oil.