The Stability of Extract Indigofera tinctoria for Color Indicator

Abstract

Color indicator was one of intelligent packaging that give information to the consumer based on color change. In the manufacture of color indicator.Indigoferatinctoria was used as a source of natural coloring agent.Indigoferatinctorialeafe contains indicanglucoside compound whith indigo color can be hydrolyzed with water to indoxyl which produce blue color. Natural dyes used as color indicator must have a certain stability that is influenced by certain factors such astemperature and pH. In the research extraction of indigo leaves was fermented for 24 hours. The extract was stored at different temperature levels at refrigerator (2 ± 2 °C), room temperature (25 ± 2 °C) and high temperature (40 °C). The effect of pH on the stability of indigo dye extract wascarried out by measuring the absorbance value at pH 1 to 14. The stability of the extract on temperature decreasewith the coefficient of determination of (R2= 0,99) by linear regression of y=0,026x+170 and the stability of extract to pH (R2=0,94) by the equator of y= 0,05x+0,016.