Sodium caseinate active film loaded clove essential oil based on konjac glucomannan and xanthan gum: physical and structural properties

In recent years, proteins and polysaccharides have been widely used to prepare environmentally friendly functional food packaging materials. However, films based only on proteins or polysaccharides perform poorly and are often used as polymer matrices blended with biologically active ingredients to prepare films. In this paper, sodium caseinate (CAS), xanthan gum (XG), and konjac glucomannan (KGM) were used as raw materials, and clove oil (CEO) was added for the development of reactive biopolymer films, with the aim of exploring the effect of CEO on the structure and physical properties of films. The morphology, rheological behavior, optical properties, thermodynamic properties and mechanical properties of the composite films were investigated. The interaction between clove oil and film matrix was determined by Fourier infrared spectroscopy, and the distribution of CEO in the network structure of the films and the compatibility properties with the film matrix were investigated by scanning electron microscopy and laser confocal microscopy. It was found that with the increase of CEO content, the film color deepened, the optical properties were modulated, the surface hydrophobicity was enhanced and the thermodynamic properties did not change significantly. The study showed how the combination of konjac glucomannan and xanthan gum colloids with clove essential oil and sodium caseinate can affect the properties of bioactive films.