Konjac glucomannan films with Pickering emulsion stabilized by TEMPO-oxidized chitin nanocrystal for active food packaging

Abstract

In this study, TEMPO-oxidized chitin nanocrystal (TOCN) stabilized oregano essential oil (OEO) Pickering emulsions were incorporated into the Konjac glucomannan (KGM) matrix to prepare an active food packaging film. OEO Pickering emulsions with 2.4% wt TOCN and 2% v/v OEO had a uniform droplet distribution and a particle size of 25.80 μm. The influence of OEO Pickering emulsions on the physical and biological properties of the KGM film was investigated. Scanning electron microscopy results showed that the Pickering emulsion was uniformly distributed in the KGM matrix and formed microstructure-sized holes in the films. The incorporation of OEO Pickering emulsion reduced the mechanical properties of the films, but the water vapor permeability firstly decreased and then increased. Meanwhile, the appropriate emulsion content can improve the film's barrier properties to light. Furthermore, the antioxidant and antimicrobial properties of the films were strengthened by OEO Pickering emulsion incorporation and mainly depended on its concentration. This study suggests the feasibility of KGM-based Pickering emulsion films for active food packaging applications.