Delivery of β-carotene to the in vitro intestinal barrier using nanoemulsions with lecithin or sodium caseinate as emulsifiers

To increase the intestinal delivery of dietary beta-carotene, there is a need to develop nanostructured food systems to encapsulate this fat soluble bioactive. The aim of this study was to evaluate the bioacessibility and bioavailability across the intestinal barrier of beta-carotene-enriched nanoemulsions stabilised with two emulsifiers (lecithin or sodium caseinate) by coupling an in vitro gastrointestinal digestion with two in vitro cell culture models (Caco-2 or co-culture of Caco-2/HT29-MTX). Nanoemulsions stabilised with lecithin had significantly higher beta-carotene in the gastrointestinal digested micellar fraction, lower beta-carotene in the Caco-2 (and Caco-2/HT29-MTX) apical compartment and significantly higher beta-carotene in Caco-2 cellular content compared to beta-carotene-enriched nanoemulsions stabilised with sodium caseinate. Finally, to assess anti-inflammatory activity of digested nanoemulsions, lipopolysaccharide stimulated macrophages were exposed to Caco-2 basolateral samples with levels of TNF-alpha and IL-beta, subsequently quantified. A TNF-alpha response from stimulated THP-1 macrophages was elicited by basolateral samples, regardless the emulsifier used to formulate nanoemulsions. This study demonstrated that beta-carotene permeability is influenced by the food derived emulsifier used for stabilising nanoemulsions, indicating that composition may be a critical factor for beta-carotene delivery.

Automated summary

The study found that the use of nanoemulsions stabilized with lecithin can enhance the bioavailability and cellular content of beta-carotene in the intestine, while nanoemulsions stabilized with sodium caseinate perform worse in comparison. Additionally, the emulsifiers in the nanoemulsions also impact the permeability and delivery of beta-carotene.