Extraction, characterization, and microencapsulation of Patin [Pangasianodon Hypophtalmus (Sauvage, 1878)] fish oil

Patin fish (Pangasianodon hypophthalmus) is a freshwater fish that gains much attention nowadays due to its abundance of monounsaturated fatty acids and a considerable amount of polyunsaturated fatty acids in its oil, particularly omega-3 and omega-6 fatty acids. The enzyme-assisted oil extraction appears to be a more environmental friendly, safer, and lower energy consumption method compared to the conventional oil extraction techniques. This study aimed to optimize the enzymatic extraction conditions of patin fish oil using the Box-Behnken design. The crude patin fish oil (PFO) extracted using the optimized extraction parameters were subsequently refined and characterized. The effects of alcalase enzyme concentration (0.5, 1.5, and 2.5%), hydrolysis temperature (45, 50, and 55 ºC), and duration (1, 2, and 3 h) towards the yield and quality of PFO were evaluated. The highest PFO yield (23.91%) with a low peroxide value (4.33 mEq/kg oil) was obtained from patin fish flesh including its viscera and extracted by using 2.46% enzymes with 1 h incubation time at 50.4 ºC. The crude PFO extracted using the optimized extraction parameters was subjected to further chemical refining in order to obtain the refined PFO. The refined PFO exhibited a low free fatty acid content (0.75%) and peroxide value (5.49 meq O2/kg oil), as well as a high saponification value (215 mg KOH/g oil). Besides, the refined PFO consisted of 48.65% saturated fatty acids, 39.98% monounsaturated fatty acids, and 11.37% polyunsaturated fatty acids, with n-3 and n-6 fatty acids contributing up to 2.65% and 8.72% of the total polyunsaturated fatty acids, respectively. The microencapsulation of PFO would be able to mask the fishy odor as well as for ease of application, especially for fortification purposes in various food products. This study investigated the influence of spray drying inlet air temperatures and core-to-wall ratios towards the physicochemical characteristics of the PFO microcapsules. Maltodextrin was employed as the primary wall material, and the PFO microencapsulation was performed using the pilot-scale spray dryer. Two main parameters, namely the inlet air temperature (160 – 180 ºC) and core-to-wall ratio (1:2 – 1:4) were varied. The full characterization (eg: moisture content, water activity, encapsulation efficiency, solubility, hygroscopicity, density properties, flowability, and powder morphology) was conducted on the PFO microcapsules. The concentration of the wall material and the spray-drying inlet air temperature significantly (p < 0.05) impacted the encapsulation efficiency and the solubility of the PFO microcapsules. Besides, the increasing maltodextrin concentration significantly (p < 0.05) decreased the hygroscopicity and enhanced the PFO microcapsules’ flowability. The highest encapsulation efficiency (91.54%) was achieved when the PFO was encapsulated using a core-to-wall ratio of 1:4 at 180 ºC. Furthermore, the PFO microcapsules produced using the optimized spray-drying parameters and formulation were found to be spherical and exhibited smooth surfaces. The high microencapsulation efficiency and good surface morphology of PFO microcapsules demonstrated a high stability of the PFO microcapsules produced using the optimized conditions. The findings justified the feasibility of PFO microcapsules being used for nutritional fortification purposes in food products or as a dietary supplement. The utilization of freshwater fish as an alternative source for fish oil production could contribute to more sustainable aquaculture growth and development.

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