Biopackaging: Tara Gum Films

In this work, we prepared and characterized water insoluble Tara gum films. Tara gum (TG) is a polysaccharide extracted from the endosperm of Caesalpinia spinosa seeds with a performance of 12% wt. TG films were evaluated as barrier material for agricultural and food industries. The films were modified in order to improve water resistance by using glutaraldehyde (Glu) as crosslinker. The crosslinking process consisted of placing the TG films in a bath containing Glu in an acidic medium for a period of 12 and 24 hours (TG-12 and TG-24) at 25ºC. Film properties were structurally studied through XRD, TGA and SEM images and operationally evaluated by measuring water vapor permeability (WVP), gas permeation and mechanical properties. WVP values decreased with increasing crosslinking time. This is due to crosslinking which hinders the diffusion of vapor molecules through the polymer matrix. Gas permeability tests showed permeabilities in the order CO2>> N2> O2. Mechanical tests indicated an increase in the elastic modulus of the film with increasing crosslinking time; this effect is due to the loss of flexibility of the crosslinked polymeric matrix.

Keywords: Films, Gas permeation, Mechanical properties, Tara gum, Water vapor permeability.