Omega-3 Fatty Acids, Lecithin, Sterols, Vitamins and Lipid Oxidation of Olein and Super Olein Fractions of Fish Oil Produced by Winterization.

To concentrate omega-3 fatty acids (-3) in fish oil (FO), olein and super olein fraction (OF) of FO were produced by winterization. For this purpose, FO was slowly cooled to -50°C (24 h), the mixture of crystallized and non-crystallized phases was separated, filtrate was coded as OF (yield 32%), 35% of OF was kept for storage study and analytical purpose, remaining 65% was further slowly cooled down to -75°C (24 h) and filtered, filtrate was coded as super olein (SF, yield 23%). GC-MS analysis showed that unsaturated fatty acids increased due to successive winterization. In OF, C18:1, C18:2, C18:3, C20:1, C20:5 (EPA), C22:1, C22:2 and C22:6 (DHA) increased to 7.85%, 19.52%, 54.16%, 17.82%, 16.31%, 41.02%, 32.43%, and 29.89% than parent FO. In SF, C18:1, C18:2, C18:3, C20:1, C20:5, C22:1, C22:2 and C22:6 increased to 9.84%, 24.35%, 61.09%, 32.10%, 39.96%, 56.81%, 39.02%, and 48.94% than parent FO. Total phenolic contents (TPC) of FO, OF, and SF were 6.59, 12.67 and 19.72 (mgGAE/mL). Lecithin content of FO, OF, and SF were 1.29%, 0.575%, and 0.19%. In SF, desmosterol, cholesterol, stigma sterol and sitosterol were 91.57, 22.51, 12.67 and 112.18 mg/100 g. Total antioxidant capacity (TAC) of FO, OF, and SF was 49.32%, 64.27%, and 85.47%. DPPH values of FO, OF, and SF were 32.14%, 39.87%, and 46.41%. Winterization significantly raised vitamin A and E in OF and SF; vitamin A content in FO, OF, and SF (0-day) were 46.28, 67.94, and 116.48 IU; vitamin E content in FO, OF, and SF (0-day) were 1238.95, 1897.65, and 2375.11 mg/100 g. At 0-day, peroxide value (POV) of FO, OF and SF was 0.22, 0.24 and 0.25 (MeqO/Kg) with no variation in sensory characteristics. The results of this study proved that -3 could be increased in olein and super OFs of FO with reasonable oxidative stability.