Modified AOAC method for indirect measurement of resistant starch and its application in development of new food materials

Abstract

Resistant starch (RS) is the starch that is not digested by enzymes in the body and is highly valuable in food. RS functions similar to dietary fiber and is being studied actively as a raw material for functional health foods. Various methods have been proposed for the quantification of RS including the Association of Official Analytical Chemists (AOAC) and Englyst methods. However, these methods remain to be optimized as their performance depends on the type and source of the RS being tested. In this study, we used a modified AOAC method to analyze the RS contents in different food materials. The RS contents was measured indirectly by both the existing and modified AOAC methods using glucose from the supernatant and not RS pellets. In addition, we evaluated the modified method using soybean samples dried in hot air. The modified AOAC and thiobarbituric acid reactive substance assays indicated that the soybean samples had a high RS content and showed a low degree of lipid peroxidation. Based on these results, the modified AOAC method can be considered a simple and accurate method for analyzing food materials with high RS contents.