Evaluation of Physicochemical Properties and Oxidative Stability of Nano-Capsules in Different Storage Conditions

the health benefits of omega-3 fatty acids, as well as the high sensitivity ofunsaturated fatty acids to oxidation of fish oil, caused the use of encapsulation of fish oil forenriching food products and drugs. this study aims to evaluate the physicochemical properties of nanoencapsulatedfish oil, and their oxidative stability during storage at 0 and 24% relativehumidity conditions. Emulsion was prepared after sonication with wall materials ofmaltodextrin (M), modified starch (Hi-cap) and whey protein concentrate (WPC) at the ratioof 1:4 (oil:wall). Emulsion and nano-encapsulated powder properties including emulsionstability, apparent viscosity, powder moisture, encapsulated coefficient, particle size andmorphology of nano-capsules were determined. The lowest amounts of creaming and viscosity were observed in M+Hi-cap+WPCand M, respectively. Moisture content in M+Hi-cap showed the highest value. The lowest andhighest particle sizes were measured in M+Hi-cap+WPC and M, respectively. Also, the bestencapsulation efficiency was obtained for M+Hi-cap+WPC. SEM photographs showed glasslikesheets of encapsulated materials with the freeze-dryer. During 21 days storage at 0 and24% relative humidity, the results showed an increase in peroxide and anisidine values. Thevalues were higher at 24% than the 0% humidity, and the best results of oxidative stabilitywere observed in M+Hi-cap+WPC treatment. Based on the findings, relative humidity is an effective factor in the oxidation offish oil nano-capsules. The use of nano-encapsulation is a practical and effective method forincreasing the stability of fish oil for enriching the food and promoting human health.