Enhancement of oxidative stability and antioxidant potential of flaxseed oil with cinnamon extract

Oxidation in edible oils and fats is one of the main problems faced by the fat and oil industry. Using natural antioxidants is considered the preferred choice to minimize the application of synthetic antioxidants in food products. The present study was conducted to extract cinnamon extract and evaluate its antioxidant potential. The cinnamon extract was incorporated in flaxseed oil samples at different concentrations of 0.5, 0.1, 0.15, 0.2, and 0.25% (v/v) and compared with the control (with no addition of natural/synthetic antioxidant) and another sample with 0.1% (v/v) of synthetic antioxidant (butylated hydroxytoluene [BHT]). The antioxidant activity of the flaxseed oil added with cinnamon extract was carried out by DPPH and FRAP assay. The extraction method, time and temperature treatments, and solvent concentrations significantly affected cinnamon extracts’ proximate composition, DPPH, and FRAP activity. Cinnamon extract showed higher flavonoid and total phenolic contents, which led to higher antioxidant activity. Phenolic contents were observed at 313.61 ± 19.83 mg GAE/100 g acetone extract. The DPPH assay showed a significant observation of 84.58 ± 3.80%, while the FRAP assay was 143.82 ± 11.21 μmol/g. During 28 days of storage, there was a significant decrease in free fatty acids, peroxide, iodine, and thiobarbituric acid values for the treatments with higher concentrations of cinnamon extract as compared to the control. The T1 and T2, exhibited PV of 4.69 and 4.53 milli-equivalents (meq/kg), respectively. The maximum value of peroxide was detected in T0 (4.78 meq/kg) and the lowest in TBHT (3.50 meq/kg), followed by T3 (3.97 meq/kg), T4 (3.94 meq/kg) and T5 (3.89 meq/kg). As compared to T0 and TBHT, cinnamon extract was significant in reducing the peroxide value. T0 showed the highest iodine value (198.51 I2/100 g), while TBHT and T5 showed the lowest iodine values of 173.76 and 175.29 g of I2 / 100 g, respectively. Moreover, T1, T2, T3, and T4 showed iodine values of 194.34, 195.10, 179.78, and 177.42 g of I2/100 g, respectively. The results revealed that the TBA value of oil increases with the increase of the storage period. T0 showed the highest TBA value (6.95 mg MDA/kg) and T5 had the lowest TBA value (5.92 mg MDA/kg). The TBA values of T1, T2, and T3 were 6.87, 6.63, and 6.68 mg MDA/kg, respectively. Overall, the cinnamon extract improved the oxidative stability of flaxseed oil as an alternative to synthetic antioxidants with no harmful effects on human health.