Preparation and Characterization of Konjac Glucomannan/Ethyl Cellulose/Zein Composite Film

In this paper, zein was added to the KGM/EC composite film solution based on the previous research about konjac glucomannan (KGM)/ethyl cellulose (EC) composite films, and the KGM/EC/zein ternary composite films were prepared by the solution casting method. By fixing the content of both the total solids and relatively strong hydrophobic components EC, the impacts of content changes of zein and KGM on the microstructure, mechanical properties, and water resistance of composite films were studied. The results of confocal laser scanning microscopy, scanning electron microscopy, and microscopic Fourier transform infrared spectroscopy showed that when the zein addition was 3%~9% of the total solid contents (corresponding to the KGM content of 67%~61%), the distribution of the components in the film-forming solution and the composite film was relatively uniform, indicating good compatibility, and the microstructure of the prepared composite film was dense. Compared with K₇₀E₃₀ composite film, its water resistance property was significantly improved (P<0.05). When the solid mixing ratio of KGM:EC:zein was 64:30:6, the obtained blend films showed the optimum film properties, with the tensile strength, elongation at break, the water contact angle, the swelling, and soluble solid loss ratio of 72.93 MPa, 16.39%, 104.2°, 502.21%, and 15.50%, respectively. This study would provide references for the development of polysaccharide/protein blend edible films.