Effect of the Emulsifier Used in Dunaliella salina-Based Nanoemulsions Formulation on the fi-Carotene Absorption and Metabolism in Rats

Scope Microalgae such as Dunaliella salina are a potential sustainable source of natural beta-carotene due to their fast growth and high adaptability to environmental conditions. This work aims to evaluate the effect of the incorporation of beta-carotene from this alga into different emulsifier-type nanoemulsions (soybean lecithin [SBL], whey protein isolate [WPI], sodium caseinate [SDC]) on its absorption, metabolization, and biodistribution in rats.Methods and results Nanoemulsions formulated with different emulsifiers at 8% concentration are obtained by five cycles of microfluidization at 130 mPa, then expose to an in vitro digestion or orally administer to rats. Feeding rats with nanoemulsions improves beta-carotene uptake compared to control suspension, especially using SDC and WPI as emulsifiers. A greater presence of beta-carotene and retinol in the intestine, plasma, and liver is observed, being the liver the tissue that shows the highest accumulation. This fact can be a consequence of the smaller droplets that protein-nanoemulsions present compared to that with SBL in the intestine of rats, which promote faster digestibility and higher beta-carotene bioaccessibility (35%-50% more) according to the in vitro observations.Conclusions Nanoemulsions, especially those formulated with protein emulsifiers, are effective systems for increasing beta-carotene absorption, as well as retinol concentration in different rat tissues.

Automated summary

This study evaluated the effect of incorporating beta-carotene from microalgae into nanoemulsions with different emulsifiers on its absorption, metabolization, and biodistribution in rats. The results showed that feeding rats with nanoemulsions, especially those formulated with protein emulsifiers, increased the absorption and concentration of beta-carotene in different tissues. The liver showed the highest accumulation of beta-carotene and retinol. Protein nanoemulsions promoted faster digestibility and higher bioaccessibility of beta-carotene.