With the aim to obtain controlled release and to preserve the antioxidant activity of the polyphenols, nanoencapsulation of white tea extract into polymeric nanoparticles (NPs) based on poly(ε-caprolactone) (PCL) and alginate was successfully performed. NPs were prepared by nanoprecipitation method and were characterized in terms of morphology and chemical properties. Total polyphenols and catechins contents before and after encapsulation were determined. Moreover, in vitro release profiles of encapsulated polyphenols from NPs were investigated in simulated gastrointestinal fluids. The antioxidant activity and stability of encapsulated extract were further evaluated. Interestingly, NPs released 20% of the polyphenols in simulated gastric medium, and 80% after 5 h at pH 7.4, showing a good capacity to control the polyphenols delivery. Furthermore, DPPH(•) assay confirmed that white tea extract retained its antioxidant activity and NPs protected tea polyphenols from degradation, thus opening new perspectives for the exploitation of white tea extract-loaded NPs for nutraceutical applications.
Keywords: antioxidant activity; controlled release; nanoparticles; white tea extract.