EFFECT OF PROCESSING ON CONSTITUENTS AND OXIDATIVE STABILITY OF MARINE OILS

Changes in the contents of neutral and polar lipids, α-tocopherol, free fatty acids and color of seal blubber oil (SBO) and cod liver oil (CLO) during different processing steps of alkali-refining, bleaching, and deodorization were monitored. Refined, bleached and deodorized (RBD) SBO and CLO contained approximately 39 and 71% less polar lipids than their crude counterparts, respectively. There was also a reduction of 98.5 and 97.4% in the corresponding free fatty acids content of RBD-SBO and RBD-CLO. The content of α-tocopherol in both oils decreased during processing, especially at the bleaching and deodorization steps. The oxidative stability of SBO and CLO following each processing step was determined by measuring peroxide and 2-thiobarbituric acid reactive substances values. Results so obtained indicated that crude oils were most stable while their refined-bleached counterparts were least stable, perhaps due to the removal of endogenous natural antioxidants such as α-tocopherol during processing of oils.