Starch–Lipid Hybrid Film as an Edible Moisture Barrier for Enhancing the Stability of Encapsulated Probiotic Bacteria

This study presents the development and evaluation of a novel edible hybrid film comprising hydroxypropyl starch (HPS), cocoa butter (CB), and sodium starch octenyl succinate (SOS) to serve as a moisture barrier in microencapsulation systems. The film was designed to enhance the stability of sensitive probiotic bacteria (Bifidobacterium animalis subsp. lactis BB-12) under ambient and humid storage conditions. Films were characterized for water vapor transmission rate (WVTR), thermal properties (DSC), molecular interactions (ATR-FTIR), wettability (contact angle), and morphology (SEM). The optimized 55:35:10 (HPS:CB:SOS w/w) formulation formed a miscible and cohesive matrix with excellent moisture barrier performance. Probiotic cells encapsulated within this matrix maintained high viability for over 180 days without secondary packaging. These findings demonstrate that starch–lipid hybrid films offer a promising strategy for enhancing bioactive stability in functional food and nutraceutical applications.