Effect of Punicalagin as natural antioxidant on the oxidative stability of Canola oil during storage

Abstract

The present study intends to determine the effect of punicalagin as natural antioxidant on stabilising canola oil during 90 days storage and also to compare its strength with the synthetic antioxidant Butylated hydroxytoluene (BHT). Canola oil samples were categorized into three groups; pure oil (control), oil with Punicalagin and oil with BHT. Peroxide value (PV) and free fatty acid (FFA) were used to estimate the primary products of oil oxidation while Thiobarbituric Acid Reactive Substances (TBARS) and P-Anisidine values (PAV) were used to estimate the secondary products. Finally, total oxidation index was calculated to evaluate the overall oxidation of oil samples. The results showed that PV, FFA, PAV and TOTOX were significantly increased in all canola oil samples with increased in storage time. In contrast, The TBARS values continued to increase from the starting storage period until 60 days and then decreased significantly until the end of the storage period. Punicalagin effectively reduces the production of the first and second oxidation products of canola oil during storage as indicated by the reduction in the PV, FFA, PAV and TOTOX of canola oil. When compared to BHT, punicalagin showed similar effect in inhibiting primary oxidation products whereas BHT showed stronger effect in reducing the secondary oxidation products. In conclusion, punicalagin can be used as a suitable replacement for chemically synthetic antioxidants on stabilising canola oil.