Characterization and comparison of oleogels and emulgels prepared from Schizochytrium algal oil using monolaurin and MAG/DAG as gelators

Abstract

Oleogels and emulgels were developed with winterized algal oil from Schizochytrium spp. rich in ω-3 fatty acids (FAs) to overcome physical limitations of using a highly unsaturated lipid source in food applications. Both gel types were developed using monolaurin or a combination of mono- and diacylglycerols (MAG/DAG) as the gelator at concentrations of 8, 10, or 12%, w/w, in oil or emulsion. A 14-day accelerated oxidation study was conducted using peroxide value, p-Anisidine value, and change in FA composition to measure the level of oxidation. Oleogel and emulgel samples exhibited a higher oxidative stability than bulk algal oil and oil-in-water emulsion as control groups, respectively. The 12% monolaurin oleogel outperformed others in oxidative stability, preventing oxidation of approximately 17.96% and 20.43% of EPA and DHA, respectively, compared to algal oil. Physical characteristics including thermal behavior, solid fat content (SFC), rheology, morphology, and polymorphism were studied. Results indicated that MAG/DAG oleogels and monolaurin emulgels were the most physically stable. The SFC of 12% MAG/DAG oleogel at 30 °C was 10.27% whereas 12% monolaurin oleogel was only 4.51%. Both gel types developed with monolaurin and MAG/DAG could be used for different applications as they exhibited desirable qualities such as oxidative stability and improved physical characteristics.