On the use of native corn starch as a standard reference material for falling number

Authors: Delwiche, Stephen - Steve; LIANG, JOSHUA - Agricultural Marketing Service (AMS, USDA)

Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/8/2020
Publication Date: 9/18/2020
Citation: Delwiche, S.R., Liang, J. 2020. On the use of native corn starch as a standard reference material for falling Number. Cereal Chemistry. 97(6):1227-1235. https://doi.org/10.1002/cche.10346.
DOI: https://doi.org/10.1002/cche.10346

Interpretive Summary: Falling Number is a method used all over the world to gauge the quality of harvested wheat, and specifically, the integrity of the starchy endosperm from which most wheat products are derived. It is a physical (starch pasting viscosity) technique used as an indirect indicator of enzymatic stability. Compared to the majority of cereals quality analytical procedures, falling number has very good precision; however, there is a need to identify a stable starch or starch-like material that can be used as a standard reference material (SRM) to ensure that instruments fall within expected levels of precision and accuracy. The current study builds on another study by one of the authors on the suitability of native (unmodified) starches from four botanical sources (corn, wheat, rice, and potato) as SRMs. That study, performed in a single laboratory, found corn starch as the best material for sake of its high precision, long shelf life, and low cost. The current study expands upon precision measurement to include the estimation of allowable values for this SRM when measured in a network of laboratories. Recommendations are made on limits for control chart operations that will ensure consistent readings from a single instrument as well as consistent averages from each laboratory in the network. National inspection programs and private cooperatives may benefit from these guidelines.

Technical Abstract: Falling Number is a method used all over the world to gauge the quality of harvested wheat, and specifically, the integrity of the starchy endosperm from which most wheat products are derived. It is a physical (starch pasting viscosity) technique used as an indirect indicator of enzymatic stability. Compared to the majority of cereals quality analytical procedures, falling number has very good precision; however, there is a need to identify a stable starch or starch-like material that can be used as a standard reference material (SRM) to ensure that instruments fall within expected levels of precision and accuracy. The current study builds on another study by one of the authors on the suitability of native (unmodified) starches from four botanical sources (corn, wheat, rice, and potato) as SRMs. That study, performed in a single laboratory, found corn starch as the best material for sake of its high precision, long shelf life, and low cost. The current study expands upon precision measurement to include the estimation of allowable values for this SRM when measured in a network of laboratories. Recommendations are made on limits for control chart operations that will ensure consistent readings from a single instrument as well as consistent averages from each laboratory in the network. National inspection programs and private cooperatives may benefit from these guidelines.