Fabrication of novel Konjac glucomannan/shellac film with advanced functions for food packaging.

In this study, a novel composite film was fabricated from Konjac glucomannan (KGM) combined with shellac (SHL) via a casting and solvent evaporation method. Rotary rheometry, field-emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC) were applied to characterize the structure of the film. Physical properties were also investigated to evaluate the effect of SHL on KGM-based films. The results indicated that KGM-SHL gels exhibit a shear-thinning behaviour when the shear rate is increased. Meanwhile, FE-SEM images confirmed that all blended films had a continuous and homogeneous appearance without phase separation. The newly formed chemical bonds after blending were observed by FTIR. Moreover, thermal tolerance and mechanical properties of the films, such as tensile strength and elongation at break, were improved by adding SHL. In addition, the presence of SHL in the films led to an increase in water resistance. Therefore, the improved KGM-SHL films can be considered as a potential material for food packaging.