Egg white nanoparticles as carriers of folic acid: physicochemical characterization and performance as a bioactive after gastrointestinal digestion

CAROLINA ARZENI; OSCAR E PÉREZ; JEAN G. J. LEBLANC

Wageningen

Congreso; 3rd International Conference on Food Digestion; 2014

COST Action FA 1005 INFOGEST

The aim of this work was to produce folic acid (FA) complexes with egg white (EW) nanoparticles and evaluate the biological activity of FA after the complexes were subjected to an in vitro digestion process. The nanoparticles were generated by applying a high intensity ultrasound (HIUS) treatment to 5% EW solutions at pH 3 and 7, with (thermosonication) or without simultaneous heating. Then, FA was added to the nanoparticles and their interaction was evaluated by measuring the fluorescent quenching. The degree of binding was assessed spectrophotometrically. The stability to a drying process was also determined by dynamic light scattering. Finally, a digestion of the nanoparticles was achieved by applying an in vitro gastrointestinal digestion protocol and the biological activity of FA on the digested samples was determined with a microbiological assay. After thermosonication at 85 °C for 20 min at pH 3, a population of particles of about 30 nm of diameter was obtained. At the same pH, but using sonication without heating a monomodal population of about 200 nm was yielded. The binding of both types of nanoparticles with FA was then promoted and a reduction of the nanoparticle fluorescence intensity was detected, which proved the existence of an interaction with FA. The percentage of binding was approximately 80% for both systems assessed. The drying process did not cause considerable changes on the particle size of the FA complexes with nanoparticles, only a few aggregates were formed. The results of the microbiological assay showed that bound FA presented a higher biological activity in comparison to the free form of the vitamin.