Comparison of Amperometric and Enzymatic Methods to Measure Damaged Starch Content in Wheat and Pulse Flours With Different Particle Sizes

ABSTRACT Background and Objectives Pulses (e.g., lentil, chickpea, and yellow pea) are nutritious and increasingly utilized in foods and gluten‐free products. During dry milling to produce flours, starch granules undergo structural modifications, resulting in damaged starch which affects flour quality. The objectives of this study were to investigate how roller dry milling affected damaged starch content in pulse flours with different particle sizes and compare the damaged starch content measured by two methods: the amperometric method (AACC 76‐33.01) and the enzymatic method (AACC 76‐31). Findings For all flour types and sizes, the amperometric method consistently gave higher damaged starch content than the enzymatic method, with fine flours ranging from 3.31% (chickpea) to 4.37% (yellow pea) by amperometric method versus 0.95%–1.52% using enzymatic method. After adjusting the iodide‐to‐damaged starch ratio, a new calibration equation was established between iodine absorption (%) and damaged starch content. Application of this calibration resulted in amperometric damaged starch values that showed strong agreement with those obtained using the enzymatic method. Conclusions The amperometric method, when calibrated using the newly established equation, can reliably quantify damaged starch content in pulse flours and provide values that correlate strongly with those obtained by the enzymatic method. Significance and Novelty This study is the first to systematically compare amperometric and enzymatic measurements of damaged starch in pulse flours, establishing a new calibration so the amperometric method can be used to accurately measure damaged starch content in pulse flours.