Effect of Glycerol on Properties of Tapioca Starch-Based Films

Abstract

The aim of study was to determine the effect of glycerol on the properties of tapioca starch films. The films containing various amounts of glycerol (0-30 %w/w) were prepared by casting method. Texture analyzer, x-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) were used to comparatively characterize the films. The result indicated that mechanical properties were depended on amount of incorporated glycerol. The films containing 0-10 %w/w of glycerol showed brittle characteristic while those containing 20-30 %w/w demonstrated elastic film, suggesting the plasticization effect of glycerol. As indicated by x-ray diffractometry, the crystallinity was increased as increasing percentage of glycerol. The 3D structural change after incorporation of glycerol in polymer chain of starch might affect the properties of films. However, the FTIR spectra did not show clear interaction between glycerol and starch. The physical entrapment of glycerol in amylose chain might be a possible explanation for the results.