Casein‐based nanocarriers for encapsulation of propolis extract: Design, fabrication, and characterization

Background: Propolis exhibits multiple biological and pharmacological properties attributedto the presence of natural bio active compounds. In spite of its potential healthy effects, itsuse in health-food and pharmaceutical products is very restricted due to its intense aroma,highly unstable, low aqueous solubility, and low bioavailability. The purpose of this study is tofabricate an appropriate, stable, and biodegradable casein-based nanocarrier as propolis deliv-ery system. Propolis-loaded casein nanocarriers were prepared at different propolis extract/caseinate ratio and assessed for physicochemical, structural, and thermal properties.Results: The nanocarriers showed an increase of particle size augmenting propolis extract/caseinate ratio and caseinate concentration. Image processing studies revealed an increasein L* parameter (89.743), while b* parameter revealed a reduction in the yellow color(14.655) increasing the amount propolis extract in the nanocarrier. Surface photomicro-graphs evidenced that an increment of propolis extract decreased the network compactnessof the nanocarriers correlated with the lower entrapment of propolis extract into carriers athigher propolis extract/caseinate ratio. X-ray diffraction pattern suggested that propolisencapsulation produced a decrement in the caseinate crystallinity while differential scanningcalorimetry and thermogravimetric/differential thermal analysis thermograms evidenced anincrement of thermal stability of nanocarrier with increasing propolis extract content.Conclusion: Propolis extract encapsulated within casein nanocarriers represented convenientphysicochemical attributes and could provide as bioactive load in food/medical system