Fabrication of sodium caseinate-polysaccharide complexes stabilized emulsion for increased stability and control release of β-carotene

The purpose of this study was to fabricate the binary complexes stabilized emulsion delivery systems for β-carotene using sodium caseinate (NaCas) and high methoxy pectin (HMP), low methoxy pectin (LMP) and ι-carrageenan (CA), and to study the stability and digestibility of the complex emulsion systems. Compared to NaCas emulsion, the complex emulsion systems had higher particle size and the absolute value of ζ-potential, and exhibited better physical stability and better protection of β-carotene from thermal degradation. It was demonstrated that the increase in viscosity of the complex emulsions and the improvement of the interfacial viscoelasticity of the NaCas-HMP and NaCas-LMP complexes were conducive to the retention of β-carotene. In vitro digestion experiments showed that the complex emulsions could pH-responsively release β-carotene in the gastrointestinal tract at a release rate of more than 70%, and the bioaccessibility of β-carotene in complex emulsions was up to 72.6%, 76.6% and 80.2% respectively, all of which were related to the interfacial and rheological properties of the complex emulsion. These results illustrate the relationship between the physicochemical properties of the complex emulsions and the stability and digestibility of the emulsion system, which facilitate the design of an emulsion delivery system for bioactive substances.