Development of bioadhesive particles for stabilizing O/W emulsions

Proteins and polysaccharides are usual materials applied for obtaining particles with different technological functionalities. In this context, chitosan (CH) is a cationic polysaccharide commonly employed for particle formation due to its mucoadhesive properties. Lectins are also suitable materials for obtaining bioadhesive particles, as they can bind to receptors of epithelial cells. Thus, in this study, we aimed to obtain bioadhesive particles based on CH, hydrolyzed chitosan (HC), and navy bean extract (containing lectin), and then evaluate the potential of these particles in stabilizing a model colloidal system (O/W emulsions). The materials were combined by electrostatic or covalent conjugation, and the effect of the combination strategy on the particle bioadhesiveness and surface activity was assessed. Subsequently, the bioadhesive particles were applied as a stabilizer of an O/W emulsion, and the emulsion stability was evaluated under storage and under in vitro digestion conditions. HC presented a lower mucoadhesiveness than CH; however, conjugation significantly increased the bioadhesiveness of HC-based particles and improved their ability to interact with and remain associated with mucin. Besides that, all evaluated particles exhibited interfacial activity, demonstrating their suitability as emulsion stabilizers. CH/NBE- and HC/NBE-stabilized O/W emulsions were stable for at least two days of storage at 25°C, showing little or no coalescence, indicating that these systems are partially stabilized by the Pickering mechanism. Regarding the in vitro digestibility, emulsions were stable in the gastric environment, but CH and HC particles aggregated and were removed from the oil/water interface under intestinal conditions, allowing lipid digestion. Additionally, both CH/NBE- and HC/NBE-stabilized emulsions showed high lipolysis (around 70% and 60%, respectively), potentially making them suitable for the targeted delivery of lipophilic compounds. This study provided relevant data on the bioadhesive particle building and may contribute to their application in colloidal delivery systems.