Use of Polyphosphates in Agar Processing

Part II. Effects of polyphosphates on strength of agar gel

Abstract

Strength of agar gel containing 50-200ppm polyphosphates was decreased with the increase in the concentration of the additives when the agar solution was boiled with the additives for one hour. Longer boiling period also resulted in the decrease of the gel strength. However, very little decrease was observed in the gel of the same composition when polyphosphates were dissolved in hot agar solution without any further heating. Reduction of gel strength by polyphosphates was enhanced by 5ppm sulfuric acid. Such reduction was irreversible. Whiteness of dried the agar was improved by the addition of polyphosphates.