Investigation into the bioaccessibility and microstructure changes of β-carotene emulsions during in vitro digestion

In this study, the influences of interfacial structure on the physical properties, bioaccessibility and microstructure changes of high pressure homogenized β-carotene emulsion during in vitro digestion were investigated. The digestive model used in this research involved the simulation of the digestive process in the stomach, duodenum and small intestine. The changes in microstructures and properties of the β-carotene droplets were monitored by light scattering, release rate determination and optical microscopy. Results demonstrated that the initial emulsifiers used to stabilize oil-in-water emulsions had a significant effect on the droplet size, particle electric charge and microstructure change during the digestion of β-carotene droplets. In general, emulsions prepared with decaglycerol monolaurate (ML750) exhibited the highest release rate (29.39%) with no notable change in particle size and appreciable discrepancy in particle electrical charge ranging from 2.26 mV to − 5.61 mV in the gastric environment. In the simulated intestine fluids, droplet sizes of whey protein isolate (WPI) stabilized emulsion changed dramatically from 579.45 nm to 1829.5 nm with the micellarization of β-carotene reaching 86.12%.Industrial relevanceHigh pressure homogenizer shows high potentials in food processing. However, the mechanisms monitoring the gastric-intestinal adsorption of these products were not well understood. In this study, the discovery of target-dependent β-carotene release in intestine for these emulsifiers provided new information for the industry of functional food.

► β-Carotene emulsions prepared with high pressure homogenizer.
► Whey protein isolates, soybean soluble polysaccharides and decaglycerol monolaurate as emulsifiers.
► Droplet size, particle electric charge and microstructure changes differ among different interfacial structures.
► ML750-emulsion exhibited high release rate in the gastric fluids.
► WPI-emulsion showed drastic droplet changes and the most significant release rate in intestine.