Preparation and characterization of flaxseed oil emulsions stabilized by chitosan/gelatin complexes and evaluation of oxidation stability

Flaxseed oil (FO) is a functional oil rich in polyunsaturated fatty acids with antibacterial and antioxidant properties. However, its application is limited due to poor stability and low water solubility. To enhance the physicochemical and functional properties of flaxseed oil, the flaxseed oil-in-water (O/W) emulsions stabilized by chitosan/gelatin (CS/GE) complexes were fabricated and evaluated based on their morphology, droplet size, and rheological properties. The results indicated that 3.5 wt% and 4.0 wt% of CS/GE complexes significantly enhanced the stability of the emulsion, due to the formation of a denser three-dimensional network structure at the oil-water interface by higher concentrations of the complexes. Moreover, the emulsions had no significant changes under varying temperatures or ionic strength. Furthermore, the analysis of primary and secondary oxidation products demonstrated that the emulsions stabilized by different CS/GE complexes significantly delayed oil oxidation, and the emulsion exhibited better oxidation stability than pure flaxseed oil. Among them, the flaxseed oil emulsion stabilized by 3.5 wt% CS/GE complexes showed better oxidation stability and superior free radical scavenging capabilities, with DPPH and ABTS scavenging rates of 67.77 % and 58.81 %, respectively. This work provides valuable insights into developing stable delivery systems to encapsulate and protect flaxseed oil for functional applications in the food industry.