Microencapsulation of fish oil with olive leaf extract instead of synthetic antioxidant and its effects on nutraceutical properties of fish oil at different inlet temperatures

Abstract

Researches on the industrial use of natural antioxidant sources obtained from agricultural by-products are of great importance in terms of adding high value to agricultural wastes that have no economic value. Since fish oils are very sensitive to heat, the use of synthetic antioxidants has been inevitable in high-heat treatments. In this study, the effects of olive leaf extract (OLE, 1500 and 2000 ppm) at different drying inlet temperatures (160, 170, and 180 degrees C) on physicochemical properties and lipid quality of fish oils during the microencapsulation process were investigated. The efficiency of OLE as a natural antioxidant was compared with a synthetic antioxidant (BHT) and no antioxidant. The lowest microencapsulation efficiency was found in the group without antioxidants and spray-dried at 180 degrees C (C-180, 70.01%). After the microencapsulation processes, free fatty acid value was determined at the rates of 5.85-6.74% oleic acid in all groups except the C-180 group. All microencapsulated groups had similar peroxide value (PV, 6.06-7.55 mEq/kg) except C-180 group (13.67 mEq/kg). The nearest SFA ratios to raw anchovy fish oil were in the groups with BHT and OLE (1500 and 2000 ppm OLE) dried at 160 degrees C. The most dramatic decreases in EPA and DHA levels after microencapsulation process were observed in the groups without antioxidant additions, and especially spray-dried at high inlet temperatures (2.22-4.72% for EPA, 3.31-8.51% for DHA). EPA and DHA levels of BHT- and OLE-added groups were found in the range of 7.11-9.68% and 11.02-17.82%, respectively. All groups were in acceptable forms in terms of morphology according to SEM images and color data. OLE had a protective effect against lipid oxidation as much as a synthetic antioxidant BHT during microencapsulation process, especially at a low inlet temperature (160 degrees C). Since the use of OLE gave good results as an antioxidant for the microencapsulation of fish oil, it can be possible to evaluate food and agricultural wastes as a substitute for synthetic antioxidants.