Physicochemical, Mechanical and Thermal Properties of Edible Film from Man Lueat (Dioscorea alata) Flour

Abstract

            Man Lueat (Dioscorea alata) flour is a biopolymer material that can be formed into an edible film. It can be contacted directly with food, consumed and naturally biodegraded. The aims of this research were to study the effect of physicochemical, mechanical and thermal properties of edible film from Man Lueat flour. The film forming solution was prepared by Man Lueat flour at 4% w/w. The glycerol was used as a plasticizer. It was studied at 3 different levels; 30 40 and 50% w/w of Man Lueat flour. The film forming solutions were formed using the solution casting method and dried at 50 °C for 16 h. Results showed that the glycerol content at different levels of the edible film from Man Lueat flour had no effect on the thickness, color, transparency and elongation at break. However, the moisture content, water solubility, swelling property and water vapor permeability of the film tended to increase when increasing the glycerol content. In contrast, the Young’s modulus and tensile strength of films tended to decrease significantly, when the glycerol content increased. Thermal properties were found that decomposition temperature of films occurred 2 stage; the first stage occurs between 50 to 130 ° C and the second stage occurs between 263 to 315 ° C. The analysis of FT-IR showed that the different levels of glycerol affected the structure of the film (3278 cm^-1). Therefore, the edible film from Man Lueat flour can be applied as a food packaging material to protect the quality of food products.