ABILITY OF THE CANADIAN GRADING SYSTEM TO SEGREGATE CANADIAN WHEAT BY ALPHA-AMYLASE LEVELS

Abstract

A survey of falling number values in carlots of most classes of wheat (Triticum aestivum L.) was undertaken between October 1985 and February 1986. The purpose was to assess the effectiveness of the present visual grading system for segregating wheat by α-amylase levels as indicated by the falling number method. In addition, the survey was used to pinpoint areas of the western Canadian prairies from which sprout-damaged wheat originated. CWRS wheat had increasing amounts of α-amylase (lower falling number values) with lower grade. The values obtained for a given grade remained relatively constant over the entire testing period. Furthermore, the interdecile range in falling number values for the samples in a particular grade was only around 110 s. Other classes of wheat (CPS, CWSWS, CWRW) exhibited lower falling number values than CWRS wheat, reflecting increased susceptibility to preharvest sprouting and/or different tolerances for maximum percentage of sprouted kernels. Over the testing period, certain grades of some classes also varied more than CWRS wheats in falling number values. The interdecile range in values for these classes was very large and there was considerable overlap in falling number between grades. This suggests that some form of α-amylase testing could be used to advantage for these classes of wheat to ensure more consistent and uniform quality.Key words: Wheat, alpha-amylase, grading, falling number