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ARS Home » Southeast Area » New Orleans, Louisiana » Southern Regional Research Center » Commodity Utilization Research » Research » Publications at this Location » Publication #343082
Title: Comparison of international methods for the determination of total starch in raw sugars: Part II

Author
item COLE, MARSHA - Orise Fellow
item Eggleston, Gillian

Submitted to: Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/1/2017
Publication Date: 4/25/2018
Citation: Cole, M., Eggleston, G. 2018. Comparison of international methods for the determination of total starch in raw sugars: Part II. Food Chemistry. 246:99-107.

Interpretive Summary: Current starch methods used in the sugar industry are negatively affected by natural cane and processing colorants, which often masks the starch-iodine measurements. Because existing industrial methods all use potato starch-based standards as references, majority of the methods results seem interchangeable. Using the USDA Starch Research method as a reference method and factory raw sugars, we are able to clearly identify that the sample’s color affected the accuracy, precision, and use of the industrial methods especially in those that omitted a color corrective step and that the methods are not mathematically equitable among each other. It was also confirmed that these methods measured mostly sample color instead of solubilized starch and explained why starch results from these methods could not be mathematically equated to the USDA Starch Research method or any industrial method. Therefore, an industrial starch method that efficiently solubilizes starch and includes a color blank is urgently needed.

Technical Abstract: Industrial starch methods in the sugar industry are affected by sugarcane-and processing-derived colorants, and it was presumed that these methods are mathematically equatable. Using the USDA Starch Research method as a reference and factory raw sugars, the impact of colorants on the accuracy, precision, limits of detection/quantification, and mathematical equatability of the starch methods were investigated. Approximately 26-55% of raw sugar color contributed to starch-I3- absorbance. The exclusion of a color blank negatively affected method accuracy and the addition of a color blank confirmed that these methods measured mostly color instead of starch. Inefficient starch solubilization and the inability to standardize sugar colorants explained why starch results from these methods could not be mathematically equated to the USDA Starch Research method or among methods. An industrial starch method that efficiently solubilizes starch and includes a color blank is urgently needed.