Change in characteristics of film based on rice starch blended with sucrose, maltose, and trehalose after storage.

Abstract

The characteristics of rice starch film blended with sucrose, maltose, and trehalose at concentrations of 0%, 10%, 20%, or 30% (w/w of the starch weight) were investigated. Relative crystallinity (RC) of the rice starch film as determined by X-ray increased with increasing sucrose concentration and the RC tended to decrease with an increasing concentration of maltose and trehalose. RC was inhibited by adding sugar in the order of trehalose, maltose, and sucrose after 28 days storage. The rice starch film with 30% added sugar showed a homogeneous matrix and a lower frequency chemical shift of the proton OH group as determined on the day of preparation; however, the film with 30% added maltose cracked after 28 days storage. Adding sugar as a plasticizer affected the properties of the rice starch film by concentration and type of sugar because of the hydroxyl groups of the sugar. PRACTICAL APPLICATION: Disaccharides, such as sucrose, maltose, and trehalose, could be used as a plasticizer in a rice starch film system. The sugar conformation might be one factor for selecting the sugar to use for starch film system. Trehalose might improve film properties by inhibiting recrystallization after storage.