Pectin-Chitosan Polyelectrolyte Complex Nanoparticles for Encapsulation and Controlled Release of Nisin

Abstract

Nisin is a broad spectrum antimicrobial effective against Gram-positive bacteria. Antibacterial activity of Nisin is reduced when it is applied in food, due to binding with food matrix components. Encapsulation of Nisin in pectin-chitosan polyelectrolyte complex was prepared to protect Nisin from losing efficacy. Systematically, a number of parameters, pectin degree of esterification (DE), m (PE): m (CHI) mass ratio and solution pH were explored and their effect on the formation of stable polyelectrolyte nano complex colloid between pectin (PE) and chitosan (CS) was determined. Electrostatic interactions between carboxyl groups on pectin and amino groups on chitosan are confirmed by FTIR. The effects of DE of pectin on Nisin-loaded encapsulation properties were studied. Nanocapsules prepared by low methoxyl pectin (LPE) had higher encapsulation efficiency (EE) and loading capacity (LC) with smaller particle size, compared with those prepared by high methoxyl pectin (HPE). The largest EE is 65.9% when m (LPE): m (CHI) ratio was 20:15 and Nisin was 7 mg. Increasing amount of Nisin had a tendency to form nanocapsules with lower EE and higher LC and particle size. Release profile of Nisin from nanocapsules was affected by pH, more amounts of Nisin released at pH 3 than at pH 6. Encapsulated Nisin showed more active antibacterial activities against S. aureus than free Nisin. Encapsulation offers great promise to improve antibacterial effectiveness of Nisin.