The gastrointestinal behavior of emulsifiers used to formulate excipient emulsions impact the bioavailability of β-carotene from spinach.

The impact of the type of emulsifier used to formulate excipient emulsions on the degradation (D) and bioaccessibility (B) of β-carotene in spinach was investigated using a simulated gastrointestinal tract (GIT). Emulsions stabilized by sodium caseinate (SC) were more prone to droplet aggregation than those stabilized by either Tween 20 or octenyl succinic anhydride (OSA)-modified starch. The fraction of β-carotene available for absorption (D × B) was also affected by emulsifier type: SC (12.0%) > Tween 20 (5.0%) ≈ OSA stabilized (2.6%) (p < 0.05). This effect was mainly attributed to differences in the digestive characteristics of the emulsifiers, which affected the transfer efficiency of β-carotene from the plant tissues to the lipid phase, lipid digestion, and mixed micelle formation. These results show the importance of selecting an appropriate emulsifier when designing excipient emulsions to enhance the bioavailability of nutraceuticals in fruits and vegetables.