Effects of milk proteins on release properties and particle morphology of β-carotene emulsions during in vitro digestion

In the present study, beta-lactoglobulin, sodium caseinate, lactalbumin and lactoferrin were used to prepare beta-carotene emulsions. The milk protein-stabilized emulsions were explored using an in vitro release model to elucidate the effects of different milk proteins on beta-carotene release properties in the stomach, duodenum and small intestine, respectively. Notable changes in the droplet size and size distribution were observed among these four oil-in-water (O/W) milk protein emulsions. In the gastric environment, the highest beta-carotene release rate (2.9%) was achieved in beta-lactoglobulin emulsion with a remarkable change in the particle size. In the simulated intestine, the best beta-carotene micellarization potency (92%) was observed in beta-lactoglobulin emulsion and its droplet diameter moderately increased from 215 nm to 471 nm. Moreover, substantial release of beta-carotene was found in the small intestine for the four types of emulsions. It was concluded that beta-carotene release in different digestive stages was characterized by the emulsion interfacial composition.