Evaluation of a standard reference material for falling number measurement
2020
Delwiche, Stephen R. | Rausch, Steven R. | Vinyard, Bryan T.
BACKGROUND AND OBJECTIVES: Falling number (FN), a long‐standing procedure that indirectly measures α‐amylase activity, is routinely used in official inspection operations and commerce to infer processing characteristics and end‐use quality of wheat. Because price may be moderated by FN, good precision of this procedure is essential. A study was enacted to search for a reference material that can be used to monitor FN instruments in a network. Because starch is the largest component of the wheat grain and responsible for the viscous behavior of paste meals, pure forms of starch were considered. Four native starches were selected, corn (from maize), potato, rice, and wheat. Weekly measurements were made over three months using two FN instruments in anticipation that eventual network monitoring programs in government and industry will consist of control charting at this frequency. FINDINGS: Corn starch produced the best precision, with a coefficient of variation (CV) of 1.4%–1.7%. The noncereal starch, potato, had the poorest precision (CV = 6.1%–6.9%). All starches were stable, showing no time effect over the evaluation period. Additional testing on corn starches from other sources (laboratory supply, wholesale, and grocery retail) produced consistent results with respect to the original corn starch. CONCLUSIONS: Pure native corn starch was the most suitable of the selected four starches for use as a standard reference material for FN. SIGNIFICANCE AND NOVELTY: Because of increased reliance on FN as a grading criterion or pricing threshold, added pressure is placed on regulatory bodies to assure the industry of the integrity of system. This work identifies corn starch as a suitable standard reference material for FN and establishes precision limits in time monitoring programs.
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