Encapsulation of pterostilbene in hydroxypropyl-β-cyclodextrin using high-pressure homogenization and pH-shift methods: Characterization, stability, and static in vitro digestion.

Abstract

This study focused on enhancing the stability and bioaccessibility of pterostilbene (PTS) by encapsulating it with hydroxypropyl-β-cyclodextrin (HP-β-CD) using high-pressure homogenization (HPH) and pH-shift methods. The encapsulation process was performed at pressures of 50, 100, and 150 MPa along with three different treatments, achieving a maximum encapsulation efficiency of 94.34% and a loading capacity of 14.82% at 150 MPa. The SEM, XRD, and FTIR analyses confirmed encapsulation by revealing significant morphological changes, crystal structure modifications, and host-guest interactions. PTS-HP-β-CD complexes retained 82.22% of PTS at 4°C (28 days) and 76% under UVB (120 min), compared to 56.03% and 21% for free PTS, respectively. Additionally, these complexes exhibited enhanced DPPH scavenging rates (44.95% at 0.02 mg/mL), nearly twice that of free PTS. In the release studies, the complexes’ release behavior aligned with the Higuchi model. Encapsulated PTS revealed lower digestion rates in in-vitro gastric (32.24% vs. 49.88 %) and intestinal phases (63.98% vs. 91.01%). Additionally, there was no observable toxicity for PTS-HP-β-CD to human epidermal keratinocytes, supporting its potential use in cosmetics, food, and pharmaceuticals. These results demonstrated that HPH combined with pH-shift methods effectively improved the stability and bioaccessibility of PTS, offering a promising strategy for its formulation.