AOAC Official Method 2002.02 Resistant Starch in Starch and Plant Materials

Enzymatic Digestion
First Action 2002
[Applicable to plant and starch materials containing resistant starch (RS) contents ranging from 2.0 to 64% on an “as is” basis.]
See Table 2002.02 for the results of the interlaboratory study supporting acceptance of the method.

A. Principle
Nonresistant starch is solubilized and hydrolyzed to glucose by the combined action of pancreatic a-amylase and amyloglucosidase (AMG) for 16 h at 37°C. The reaction is terminated by addition of ethanol or industrial methylated spirits (IMS) and RS is recovered as a pellet by centrifugation. RS in the pellet is dissolved in 2M KOH by vigorously stirring in an ice–water bath. This solution is neutralized with acetate buffer and the starch is quantitatively hydrolyzed to glucose with AMG. Glucose is measured with glucose oxidase–peroxidase reagent (GOPOD), which is a measure of RS content. Nonresistant starch (solubilized starch) is determined by pooling the original supernatant and the washings and measuring the glucose content with GOPOD.