Marine sulfated polysaccharide affects the characteristics of astaxanthin-loaded oleogels prepared from gelatin emulsions

Abstract

In this research, gelatin (Gel), κ-carrageenan (Car), and astaxanthin (AST) were utilized to assess the properties of Gel-Car-AST emulsions and emulsion-templated oleogels. Results indicated that Car addition notably decreased particle size and increased potential absolute value of emulsions during storage period. Moreover, Car addition reduced instability indices for Gel-0.1% Car-AST (0.018), Gel-0.5% Car-AST (0.008), and Gel-1.0% Car-AST (0.007) emulsions compared with Gel-AST emulsion (0.306), suggesting that Car addition improved the emulsion's stability. The emulsions' rheological results revealed a presence of weak gel-like behavior primarily characterized by elasticity, indicating that Car addition enhanced the emulsions' ability to withstand shear resistance and viscoelastic properties. The addition of Car into oleogels resulted in reduced oil loss rate, delayed thermal degradation, and improved viscoelasticity, shear resistance, thixotropic recovery properties, high-temperature resistance, and overall stability, especially for Gel-1.0% Car-AST oleogel. Furthermore, Car addition resulted in increased antioxidant capacity, decreased levels of oxidation products, slowed AST degradation, facilitated the rapid releases of free fatty acids (FFA) and AST in the course of intestinal digestion, and enhanced the bioavailability of AST in oleogels. FFA release rate and bioavailability of AST in oleogels were as follows: Gel-AST (33.06%, 55.80%), Gel-0.1% Car-AST (37.32%, 67.38%), Gel-0.5% Car-AST (36.18%, 79.6%), and Gel-1.0% Car-AST (58.22%, 85.42%) respectively. Results demonstrated that Gel-Car-AST oleogels displayed better structural stability, higher gel strength and AST bioavailability. These findings offer a theoretical basis and novel insights for preparing oleogels derived from protein-marine sulfated polysaccharides loading AST through the emulsion-templated method, with potential applications in the food industry.