Nisin Adsorption in Colloidal Systems Formed with Phytoglycogen Octenyl Succinate

While antimicrobial compounds are often used against food pathogens, they are liable to quick degradations in foods. One way to achieve their sustained efficacy is through the use of protective delivery systems. The overall goal of this study was to understand the interactions between nisin, an antimicrobial peptide, and phytoglycogen octenyl succinate (PG-OS), a dendrimer-like amphiphilic carbohydrate polymer in aqueous (non-emulsion) and emulsion based colloidal systems. Nisin interacts with PG-OS particulates following a Langmuir monolayer adsorption pattern in both systems. The monolayer adsorption capacity (Q_m) ranged from 37.6 to 106.4 μg/mL in non-emulsion, and was 181.8 μg/mL in PG-OS stabilized emulsion. At the same doses of PG-OS (5.0 mg/mL) and nisin (200 μg/mL), the concentration of adsorbed nisin in emulsion and non-emulsion were 157 and 22 μg/mL, respectively. This study showed that both the chemical nature and physical distribution of PG-OS particulates would affect nisin adsorption, which may provide a method for designing carbohydrate colloidal systems to achieve effective protection of antimicrobial compounds for foods.