Preparation, characterization and host-guest interaction of photothermal-responsive modified carboxymethyl chitosan microcapsules

Heterocyclic fragrance compounds possess unique aromas that can enhance flavor of products, but their applications are limited due to high volatility, short storage durations, and thermal instability. This paper used porphyrin grafted carboxymethyl chitosan (CMCS) as wall material and selected four heterocyclic fragrance compounds as core materials to develop an effective controlled release system of photothermal-responsive microcapsules. The optimal preparation process for microcapsules was determined through response surface methodology (RSM). The Scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and Flourier transform Infrared Spectroscopy (FTIR) results confirmed the successful preparation of microcapsules. Photo-release performance and thermo-gravimetry (TG) demonstrated excellent photothermal-responsive behavior. The results of MD indicated that the system of microcapsule exhibited enhanced stability and superior convergence, with van der Waals forces being the primary interaction between hosts and guests. Notably, the 3-acetylpyridine/5-( p -aminophenyl)-10,15,20-triphenylporphyrin-carboxymethyl chitosan (ATPD/AC) displayed strongest intermolecular force among the other microcapsules, which performed the highest complexation strength with guest and the highest stability. This study provided a theoretical foundation for constructing stable controlled release systems for heterocyclic fragrance microcapsules.