Two Alternative Methods to Predict Amylose Content of Rice Grain by Using Tristimulus CIE Lab Values and Developing a Specific Color Board of Starch-iodine Complex Solution

Abstract

Amylose content was predicted by measuring tridimensional Commission Internationale de l‘Eclairage (CIE L*a*b*), L*a*b* values in starch-iodine solutions and building a regression model. The developed regression model showed a highly significant relationship (R2=0.99) between the L*a*b* values and the amylose content. Apparent amylose content was strongly and negatively correlated with L*a*b* values. This method could be used to predict amylose content in rice. The conversion of L*a*b* values to red, green, blue (RGB) values and to color hexadecimal codes allowed reproducing the colors of starch-iodine solution and making an explicit color board. Using this specific color board, we could sort entries into their respective classes and easily estimate their apparent amylose content.

Keywords

• Amylose content
• Amylose-iodine colorimetry
• Color chart
• Commission Internationale de l’Eclairage (CIE L*a*b*)
• Rice