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

Background: Propolis exhibits multiple biological and pharmacological properties attributed to the presence of natural bio active compounds. In spite of its potential healthy effects, its use 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 to fabricate an appropriate, stable, and biodegradable casein‐based nanocarrier as propolis delivery 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 increase in 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 photomicrographs evidenced that an increment of propolis extract decreased the network compactness of the nanocarriers correlated with the lower entrapment of propolis extract into carriers at higher propolis extract/caseinate ratio. X‐ray diffraction pattern suggested that propolis encapsulation produced a decrement in the caseinate crystallinity while differential scanning calorimetry and thermogravimetric/differential thermal analysis thermograms evidenced an increment of thermal stability of nanocarrier with increasing propolis extract content. Conclusion: Propolis extract encapsulated within casein nanocarriers represented convenient physicochemical attributes and could provide as bioactive load in food/medical system. [ABSTRACT FROM AUTHOR]