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Chitosan nanocapsules containing polyunsaturated fatty acid (PUFA) concentrates from tuna oil, with EPA + DHA contents around 57% (w/w), were developed by emulsification process, using different chitosan concentration (1.0%, 1.5%, 2.0%, w/v) and stirring speed (10,000, 15,000, 20,000 rpm). The effects of these parameters on particle size and zeta potential were evaluated. The physical and oxidative stabilities were used to measure the product quality during storage. Chitosan concentration, stirring speed and its interaction significantly affected (p < 0.05) the particle size. In addition, chitosan concentration significantly affected (p < 0.05) the zeta potential of nanocapsules emulsion. Based on the results of physical and oxidative stabilities, the nanocapsules were stable for 30 days under refrigeration temperature (7 °C), and with 1.5–2% chitosan resulted in improved protection against oil oxidation. The nanocapsules produced with 2% chitosan and 10,000 rpm showed the lowest variations of polydispersity index and nanocapsules size after 30 days of storage (221.8 ± 3.0 nm). These conditions can be considered the most suitable to produce nanocapsules of PUFA concentrates from tuna oil using chitosan as wall material. These nanocapsules showed physical characteristics and oxidative stability, which could enable their application in the food industry, representing an important source of EPA and DHA fatty acids. [ABSTRACT FROM AUTHOR]

Summary: This work aimed at oil extraction from catfish (Netuma barba) heads through the CO2 supercritical fluid (SFE‐CO2), and the ranges of supercritical conditions were extraction time (1 and 3 h), temperature (40 and 60 °C) and pressure (15 and 25 MPA). The crude oil from catfish heads presented the yield in the thermomechanical extraction was 86% compared to the Bligh and Dyer method, with concentrations of eicosapentaenoic acid (EPA) and docosahexaenoic acid DHA of approximately 9.0% and 11.9%, respectively, in the catfish oil profiles after the refining process. In the supercritical extraction, the highest yield was around 84% at 25 MPa and 40 °C in 3 h, with lower concentrations of EPA and DHA, respectively, 2.1% and 9.1%. At 25 MPa, 60 °C and 3 h, the extraction yield was around 81%, with concentrations of EPA and DHA about 3.4% and 10.0%, respectively. The highest concentration of EPA and DHA was 18.3% found in the experiment at 25 MPa, 40 °C and 1 h. The catfish head oil obtained by supercritical fluid extraction process (SFE‐CO2) showed similar characteristics to oil obtained by thermomechanical extraction and chemically refined. Thus, SFE‐CO2, besides being a promising potential for use of the fish waste, leads to sustainable food production through green technology. [ABSTRACT FROM AUTHOR]