Investigating the structural characteristics of nanoencapsulation white tea extract using polylactic glycolic acid (PLGA)

The objective of the present study is to optimize the extraction of white tea extract (WTE) containing the highest concentration of polyphenolic compounds (TPC) under ultrasound intensity, ultrasound time, and different solvents, and then to investigate the effect of nanoencapsulation using PLGA on the structural characteristics of the optimized extract. The results of the investigation showed the effect of the time and intensity of ultrasound as well as the type of solvent used on the extraction performance of the extract. Thus, the optimal conditions were obtained by using methanol solvent and applying 15 min of time and 70% ultrasound intensity to extract the extract with the highest antioxidant capacity and maximum TPC, respectively, at the rate of 77.65% and 68.38 mg/g. The preparation of white tea extract nanocapsules (WTE-NCs) using PLGA was based on solvent-emulsion evaporation and ultrasound. WTE-NCs were investigated in terms of efficiency and release of WTE micro-coating and structural properties through particle size determination, morphological analysis, and FT-IR. The micro-coating efficiency was 91.89% on the first day, which decreased to 76.16% after 22 days. The particle size analysis results showed that WTE-NCs with a particle size of 68.36 nm increased to 447.23 nm after six months. In terms of morphology, WTE-NCs had a spherical structure. The present study’s findings showed that micro-coating using PLGA can effectively protect and cover WTE.