Extraction and encapsulation of squalene-rich cod liver oil using supercritical CO2 process for enhanced oxidative stability

Abstract

We produced squalene-rich cod liver oil (CLO) and solid-lipid particles (SLP) were produced using supercritical carbon dioxide (SC-CO2) extraction and gas saturated solutions (PGSS) processes respectively. Polyethylene glycol (PEG) was used for encapsulation. The encapsulation yield and efficiency (EE) of the SLPs obtained from the oil under 25 MPa, 4:20 (SCO:PEG, w/w) condition, were 71.13 % ± 0.44 % and, EE 35.52 % ± 0.22 %, respectively. The optimum conditions included 25 MPa, 4:20 (SCO:PEG, w/w), the bulk density and tapped density of the SLPs were 0.30 ± 0.02 and, 0.33 ± 0.02 g/cm3, respectively. The corresponding Carr’s index (CI) value was the lowest at 9.09 ± 0.97 and the smallest particle size was 315.83 µm with 9-PEG, making it suitable for commercial applications. Microencapsulated CLO was characterized using scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential scanning calorimeter (DSC). Upon evaluation, the antioxidant activity of squalene was enhanced with 9-PEG at ABTS+ 142.60 ± 5.71 mgTE/g and, DPPH 30.38 ± 1.44 mgTE/g. Encapsulated CLO (22.50 ± 0.30 meq/kg) showed improved oxidative stability than bare CLO. Therefore, encapsulation of functional oils obtained via SC-CO2 extraction using PGSS process inhibits oxidation and facilitates its commercial applications.