Characterization of edible films prepared from Jerusalem artichoke extracts

Inulin can add additional values to food due to its beneficial nutritional attributes, and it has not yet been studied as a material for film forming. The objective of this research was to characterize the properties of edible films derived from inulin, which was extracted from Jerusalem artichoke. Transparency, moisture content and water vapor permeability (WVP), tensile strength (TS) and elongation at break (%E) of the films formulated by different inulin (30, 60, 90, 120 mg L-1 with 30 ml L-1 of glycerol) and glycerol (10, 30, 50, 70 ml L-1 with 60 mg L-1 of inulin) content were determined. Results showed that the edible films were transparent and clear enough to be used as see-through packaging materials. The films formulated with 60 mg L-1 inulin exhibited the lowest moisture content and WVP value, and the highest TS values. The moisture content, WVP and TS of films increased whereas %E decreased with the increase of glycerol content (30, 50 and 70 ml L-1). It is suggested that the minimum permeability concentration for glycerol was 30 ml L-1 in our experiment. The results indicated that glycerol and inulin may directly affect the network structure of the films through molecule interactions in the inulin-water system. Our hypothesis about types of molecule interactions gives a possible reason for the properties of the inulin edible films.