Stabilizing flaxseed oil with individual antioxidants and their mixtures

In vitro reducing power tests of tea polyphenols (Tp), tert-butylhydroquinone (TBHQ), and monoglyceride citrate (MGC) revealed that, at certain concentrations, Tp + TBHQ displayed a strong reductive capacity. Moreover, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity tests showed that Tp + TBHQ was effective (p < 0.05) in quenching DPPH radicals. The effectiveness of Tp + TBHQ towards the radical-scavenging activity was also found to be increased when their concentrations were increased. The oxidation stability of flaxseed oil (FO) was investigated as a function of time at high temperature, in the absence and presence of antioxidants; the peroxide value (PV) and p-anisidine value of FO were determined as indicators of oxidation at 60°C during 20 days. The results revealed that Tp₂₀₀ + TBHQ₁₀₀ (subscripts refer to amounts in mg/kg) had noticeable reduction effects on the oxidation (PV and p-anisidine) of FO compared with TBHQ₂₀₀ regarding the PV, and when compared with the mixture of TBHQ₁₀₀ + MGC₁₀₀ regarding the p-anisidine value. However, according to Rancimat tests, the ternary mixture (Tp₂₀₀ + TBHQ₁₀₀ + MGC₁₀₀) was found to be more effective in controlling FO oxidation. The induction periods for FO containing Tp₂₀₀ + TBHQ₁₀₀ + MGC₁₀₀, TBHQ₁₀₀ + MGC₁₀₀, and Tp₂₀₀ + TBHQ₁₀₀ were 8.305, 6.905, and 6.8020 h, respectively, whereby no significant differences were observed between TBHQ₁₀₀ + MGC₁₀₀ and Tp₂₀₀ + TBHQ₁₀₀ (p < 0.025).Practical applications: Flaxseed oil is an unstable vegetable oil due to its high content of PUFA, which are mainly composed of α-linolenic acid (ALA). One effective way to ensure a high quality of lipids and lipid-containing products, and to prolong their storage time, is to stabilize them by addition of suitable antioxidants. The stabilization of FO will help to increase both its shelf life and to improve its use in different applications. According to recent studies, FO contains many components that are beneficial for human health, especially ALA which can contribute to increasing the DHA and EPA content in the body. FO is believed to provide benefits in the prevention and treatment of heart diseases, arthritis, inflammatory, and autoimmune diseases.