Oxidative stability of microencapsulated fish oil with rosemary, thyme and laurel extracts: A kinetic assessment

Antioxidant activity of rosemary (R), thyme (T) and laurel (L) extracts was evaluated for protection of fish oil during microencapsulation and heat-induced degradation. For this purpose, oil stability was optimised by comparing oxidation levels of fish oils which are exposed to high temperatures ie., 23 °C, 40 °C, and 60 °C in the presence of natural and commercial antioxidants ie., 1000 (1) 1500 (2) ppm extracts and two control groups without and with BHT (250 ppm) (C1, C2). Then, peroxide formation kinetics of the microcapsules were also determined. Peroxide values (PV) of microencapsulated fish oil in the presence of 1500 ppm rosemary (R2) were lower (3.08 mEq O2/kg oil) than the control group with commercial antioxidant (C2, 4.25 mEq O2/kg oil). Thiobarbituric acids (TBA) of R2, R1, and L2 (0.36 mmol MDA/kg oil, 0.56 mmol MDA/kg oil, 0.59 mmol MDA/kg oil respectively) were also lower than C2 (0.64 mmol MDA/kg oil). Besides, R2 and R1 (31.62 kJ/mol, and 30.82 kJ/mol) had higher activation energies than C2 (30.46 kJ/mol). As a result, it is revealed that rosemary and laurel extracts can successfully be applied to anchovy oil for improving the oxidative stability in microencapsulation by spray drying.