AN INTER-LABORATORY STUDY OF STARCH DEGRADING ENZYME ASSAYS

Abstract

The reliability of specific colorimetric assays for the main starch degrading enzymes, α‐amylase, β‐amylase and limit dextrinase was investigated by conducting an inter‐laboratory collaborative study. Three malt samples were assayed in duplicate in 14 laboratories. The repeatability (r) within laboratories was good for α‐amylase and β‐amylase assays. Between‐laboratory reproducibility (R) was acceptable (CV_R 9.2–14%). Errors for limit dextrinase were higher. Repeatability was good at high enzyme concentrations (CV_r = 2%) but increased at low enzyme concentrations. Reproducibility was relatively poor (CV_R‐27–33%).