Cereal Foods World, Vol. 63, No. 1
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Low Falling Numbers in the Pacific Northwest Wheat Growing Region: Preharvest Sprouting, Late Maturity Amylase, Falling Number Instrument, or Low Protein?
ADB Wheat Consulting, Moscow, ID, U.S.A.
Falling number is a rapid test that measures the impact of amylase on starch. Results are used to place an economic value on wheat in the marketplace. There are multiple factors beyond amylase that influence falling number values, however, that are not accounted for in this grading system, and the test itself has inherent variation. Other tests may be more precise and robust but are not widely used in grain grading or the marketplace. The falling number test serves both the buyer and end user well in providing assurance that a grain lot is truly sound if falling number results are above 300 sec, or even 350 sec. When amylase results from the presence of late maturity amylase (LMA), the condition is concealed and goes unnoticed until the grain is harvested and graded using the falling number test. Low falling number results in 2016 in the U.S. Pacific Northwest were due to LMA—significant damage to the crop had occurred early in grain development and was not known until an amylase test was performed. In other crop years, low falling number values for very low protein wheat or partial waxy wheat may lead to downgraded grain lots even though amylase is absent. Reexamining grain grading standards relative to their use in establishing grain prices, with an emphasis on the degree of variation implicit in falling number testing, should be considered. Alternative tests may assist in better interpreting falling number results, including direct amylase testing or alternative starch pasting tests. Removal of LMA genes from breeding germplasm and released cultivars is the only sure way to rectify the occurrence of LMA.
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