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

Scope Microalgae such as Dunaliella salina are a potential sustainable source of natural β-carotene due to their fast growth and high adaptability to environmental conditions. This work aims to evaluate the effect of the incorporation of β-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 β-carotene uptake compared to control suspension, especially using SDC and WPI as emulsifiers. A greater presence of β-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 β-carotene bioaccessibility (35%–50% more) according to the in vitro observations. Conclusions Nanoemulsions, especially those formulated with protein emulsifiers, are effective systems for increasing β-carotene absorption, as well as retinol concentration in different rat tissues. ; This work was funded by the project AGL2015-65975-R (FEDER, MINECO, UE) and project RTI2018-094268-B-C21 (MCIU, AEI; FEDER, UE). Author Júlia Teixé Roig thanks the University of Lleida for the pre-doctoral grant. The authors would also thanks Monzón Biotech (Spain) for kindly providing alga Dunaliella salina.