Studies on Moisture Sorption Isotherms of Wheat Starch Edible Films at Different Glycerol Content and emperature

The water-binding characteristics of wheat starch films (WSF) were scrutinized through the establishment of water vapour adsorption isotherms at 5 °C, 15 °C, 25 °C and 40 °C. Starch films were obtained by casting after mixing native wheat starch at 90 °C for 15 min with different contents of plasticizer (glycerol) (0, 20, 30, 40 and 50 g/100 g starch). Films plasticized with glycerol, under all temperatures and RH conditions (11-86%), adsorbed more moisture with higher initial adsorption rate, and films with higher plasticizers contents revealed higher equilibrium moisture contents. Reduction of the temperature enhanced the equilibrium moisture content and monolayer water of the edible films. The Guggenheim-Anderson-de Boer (GAB) was superior to either the Peleg or BET model as a model for the measured isotherms.

کلیدواژه ها:

Edible Film ، Glycerol ، Wheat Starch ، Moisture Sorption Isotherm