Development of casein‐based nanoencapsulation systems for delivery of epigallocatechin gallate and folic acid

The potential application of casein‐based nanocarriers in the encapsulation of hydrophobic bioactives has been reported already. However, to our knowledge, there is not any report about the application of re‐assembled (re‐combined) casein micelles or casein nanoparticles in the encapsulation of hydrophilic nutraceuticals. This is the first manuscript in which the interaction between sodium caseinate and two hydrophilic ligands including EGCG and folic acid has been studied. This manuscript describes our findings about the potential application of re‐combined casein micelles and casein nanoparticles in the encapsulation technology. The results showed that casein‐based nanocarriers may be efficiently used for the transporting of hydrophilic nutraceuticals.

Abstract

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.

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