Fabrication, characterization and controlled release properties of yak casein cold-set gels

Abstract

The casein cold-set gel was prepared from yak qula and the gel characterizations and embedding features were investigated by means of rheological property analysises, texture profile analysises, laser confocal microscopic observation, and in vitro simulated digestion experiment. The results showed that the hardness and elasticity of the gel were increased with the concentration of glucono-δ-lactone (GDL) and NaCl. Better water holding capacity (WHC) was observed in the gel with a lower concentration of GDL (1%) and NaCl (0.2M) than that with high concentration of GDL (2%) and NaCl (0.2M, 0.4M). GDL significantly affected the energy storage modulus (G’) and loss modulus (G”) values. Confocal laser scanning microscopy (CLSM) observations and fractal analysis further demonstrated that electrostatic interaction was the major force in the gel formation, which was characterized by reactive limited polymerization. The in vitro experiment on casein cold-set gel encapsulation of bioactive ingredient (Que) showed favorable encapsulation and controlled-release performance. In conclusion, Yak casein (YCN) cold-set gel would be an useful matrix for the application of encapsulation, protection, delivery and controlled-release of some bioactive components.