EFFECT OF ROSEMARY EXTRACT ADDITION ON OXIDATIVE STABILITY AND QUALITY OF HEMP SEED OIL

Rosemary extract (RE) is a natural antioxidant, whose effectiveness depends on the extraction method. It can be considered an alternative for synthetic antioxidants in the food industry. The aim of this research was to evaluate the rosemary extract antioxidant efficiency, obtained by various solvents, on hemp oil quality and storage stability. The following solvents were used to extract antioxidant compounds from rosemary leaves: ethanol (RE-ETOH), methanol (RE-MEOH), acetone (RE-AC) and ethyl acetate (RE-ETH_ACE). The complex evaluation of the antioxidant properties of those extracts was performed. In addition, their impact on the oxidation dynamics of hemp oil throughout the storage period was tested. Their effectiveness was compared to butylated hydroxytoluene (BHT). The highest total phenolic content (TPC) and antioxidant capacity were characterised by RE-MEOH and the lowest by RE-ETH_ACE. The lowest thiobarbituric acid reactive substances (TBARS) value after 14 days of storage, however, was noted for RE-MEOH and RE-ACE (1.01 and 1.18 μmol/kg respectively). The addition of rosemary extract indicates a greater antioxidant effect for some n-3 fatty acids, e.g. α-linoleic acid, than BHT. Rosemary extract has a positive effect in reducing the oxidation process and can provide a natural alternative to synthetic antioxidants, especially for products with a high n-3 fatty acid content.