Modification of Sago Starch for Edible Coating

Abstract

The edible coating film was prepared using native sago starch and modified sago starch with acetylation. The effects of acetic anhydride (7.5%, 15%, 30%, and 45% w/w) on swelling properties of wheat starch granules, amylose content, lipids content, protein content, a degree of substitution, percent acetylation, and gelatinization temperature were investigated. Modified sago starch and native starch were characterized by Fourier Transform Infrared (FTIR), X-ray Diffraction (XRD), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM). As a result, modified sago starch containing 45% w/w acetic anhydride have a degree of substitution 0.12 with acetylation 45%. All modified starch granules exhibited higher amylose content compared to native starch. Higher amylose contents inhibit the extensive granule swelling power, so swelling power decreased while increased amylose content. Edible coating film used were starch concentration 5.0% w/w, and glycerol content 1.0% v/v. Edible coating film made from native and modified sago starch have been studied to hydrophobicity, Fourier transforms infrared (FTIR), water vapor absorption, and scanning electron microscopy (SEM).