In this work, binding characteristics of two hydrophilic nutraceutical models, namely epigallocatechin gallate (EGCG) and folic acid (FA), to sodium caseinate were studied by fluorimetry technique. EGCG-loaded casein molecules were then converted to either re-combined casein micelles (r-CMs) or casein nanoparticles (CNPs). Binding stoichiometry of EGCG and FA was 0.81 and 1.02, respectively. As determined by DLS technique, the average particle size of r-CMs prepared at 0.5% concentration was 66.2 nm. Thermal treatment (74°C, 20 s) had significant (p < 0.05) influence on the particle size of nanocarriers, but not nutraceutical loading. The average size of CNPs was larger than that of r-CMs. The encapsulation efficiency (EE) of EGCG was 85%, and its ejection from the nanocarrier was less than 3% over 21 days. Alkaline conditions resulted in higher release of EGCG than acidic conditions. r-CMs were more effective than CNPs during the protection of EGCG against heat-induced degradation. TEM micrographs confirmed the formation of r-CMs.
Keywords: EGGC; folic acid; nanoencapsulation; re‐combined casein micelle.