Validation of a New Method for Flour Diastatic Activity (Maltose Value, MV): Collaborative Study

ABSTRACT Background and Objectives The diastatic activity of wheat flour is a critical parameter for assessing its fermentation potential in breadmaking. The conventional assay (AACC Approved Method 22‐15.01) involves a 1‐h enzymatic digestion of starch to maltose, followed by quantification of maltose via a standard reducing sugar titration. The result is reported as the Maltose Value (MV). This study introduces an alternative method that retains the initial 1‐h digestion step but replaces the titration with a colorimetric assay. In this approach, maltose generated in the 1‐h digestion is enzymatically converted to glucose using amyloglucosidase, and the resulting glucose is quantified using a glucose oxidase/peroxidase (GOPOD) reagent. The amount of maltose is then calculated stoichiometrically, assuming complete conversion of maltose to glucose. This new method offers a simpler and safer alternative to the traditional assay by eliminating the use of hazardous chemicals while maintaining accuracy in measuring diastatic activity. Findings The newly developed method demonstrated strong correlation with the conventional titration‐based assay exhibiting high repeatability and a low relative standard deviation (RSD r < 2%) in single‐laboratory validation. In a collaborative study, 13 laboratories analyzed 12 wheat flour samples, comprising two samples from each of six distinct flour types with varying MV. All flours were milled in Japan from wheat sourced from the United States, Canada, Australia, and Japan. Participants received randomly coded samples and conducted analyses under blinded conditions. Out of 72 individual data points collected, three pairs were identified as Cochran outliers. The estimated relative standard deviation of repeatability (RSD r ) ranged from 1.2% to 3.9%, while the relative standard deviation of reproducibility (RSD R ) ranged from 3.9% to 6.6%, indicating acceptable inter‐laboratory consistency. Conclusions The variability observed in the statistical evaluation of the method falls well within acceptable limits for assays measuring diastatic activity. This novel approach offers a reliable and straightforward alternative to conventional methods, enabling accurate assessment of flour diastatic activity without the use of non‐food‐grade or unsafe chemicals.