Microencapsulation of docosahexaenoic acid (DHA) with four wall materials including pea protein-modified starch complex

Omega-3 fatty acids, specifically docosahexaenoic acid (DHA, 22 carbons and 6 double bonds) are fundamental compounds for a healthy diet. However, due to their unsaturated nature, omega fatty acid-rich oils are chemically unstable and susceptible to oxidative deterioration. The oxidation results in production of free radicals and unpleasant tastes, negatively impacting the shelf-life, sensory properties, and acceptability of food products. This study was conducted to examine the effect of wall materials on protection of DHA in canola oil against oxidation. A total of 4 wall materials including pea protein isolate (PPI), pea protein isolate - modified starch complex (PPI-MS), Tween 20, and SDS were used for microemulsion preparation with canola oil containing DHA. The freeze-dried powders were analyzed with respect to physicochemical characteristics, oxidative stability, and release properties. The results showed that the PPI-MS as a natural polymeric wall material exhibited similar or better encapsulation efficiency and acceptable level of peroxide value compared to the synthetic surfactants (Tween 20 and SDS). The utilization of protein-polysaccharide complexes enabled the incorporation of specific properties of each biopolymer to further improve emulsion stability for the production of capsules with improved oxidative stability.