ASSESSMENT OF PRIMARY AND SECONDARY OXIDATION PRODUCTS DURING STORAGE AND HEATING OF LINSEED OIL ENRICHED WITH NATURAL EXTRACT

摘要

The aim of the present study was to assess the antioxidant activity of anthocyanin extracts added to linseed oil. The hydroethanolic extract obtained from freeze-dried black currants shows high content of total anthocyanins (1041.32 mg 100 g~(-1) DM), and phenolics (1209.90 mg GAE 100 g~(-1) DM). The results indicate lower levels of free fatty acids as measured by acid value in samples containing anthocyanin extract compared to those in sample with α-tocopherol. Good oxidative stability was obtained during 14 days of storage at 60°C. The total oxidation of oil during 18-day storage at 60°C calculated from peroxide and p-anisidine values decreased in linseed oil containing anthocyanin extract compared to sample containing atocopherol and to control (untreated oil). Differential scanning calorimetry and thermogravimetry analyses, hereby used as rapid methods for evaluation of oil oxidative stability, reveal the antioxidant effect of anthocyanin extract and α-tocopherol during the first 6 days of oil storage at 60°C. After 13 days, the effects become similar due to the thermal degradation of such compounds added to linseed oil. The obtained results highlight the potential of black currants extract to delay lipid oxidation in linseed oil, which may replace synthetic antioxidants used in edible oil industry.