Spruce galactoglucomannan films show promising barrier properties

Films were prepared from sorbitol-plasticized spruce galactoglucomannans (GGM), which are a potential new product from forest biorefineries. GGM were also mixed with konjac glucomannan (KGM), poly(vinyl alcohol) (PVOH), and cellulose nanowhiskers (CNW). Permeability properties of GGM-based films were compared to those of films from commercial mannans, namely KGM, guar gum galactomannan (GG), and locust bean gum galactomannan (LBG). GGM-based films had lower water vapor permeability than the films formed from any of the other mannans. The oxygen permeability of GGM films was of the same magnitude as that of commercial polyethylene/ethylene vinyl alcohol/polyethylene laminate film. The aroma permeability of GGM films was low. All films were transparent in the visible region, but GGM films blocked the light transmission in the ultraviolet region of the spectra.