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ARS Home » Southeast Area » New Orleans, Louisiana » Southern Regional Research Center » Commodity Utilization Research » Research » Publications at this Location » Publication #343933

Research Project: Developing Technologies that Enable Growth and Profitability in the Commercial Conversion of Sugarcane, Sweet Sorghum, and Energy Beets into Sugar, Advanced Biofuels, and Bioproducts

Location: Commodity Utilization Research

Title: Development of a new industrial method to measure starch in sugar products

item COLE, MARSHA - Orise Fellow
item Eggleston, Gillian

Submitted to: International Sugar Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/1/2018
Publication Date: 2/2/2019
Citation: Cole, M.R., Eggleston, G. 2019. Development of a new industrial method to measure starch in sugar products. International Sugar Journal. 121(1442):122-132.

Interpretive Summary: In sugarcane processing, starch is an impurity that negatively affects processing and reduces the quality of the sugar end-product. Existing industry methods used to measure starch in raw and refined sugars, measures mostly soluble starch with little impact in solubilizing insoluble starch. The purpose of this study was to develop an industrial method to measure total starch and determine the concentration of insoluble and soluble starch in various sugar products containing both high and low quantities of insoluble starch. The USDA Starch Factory/Refinery method uses a combination of microwaving and inexpensive chemicals to rapidly and selectively solubilize starch with high precision and accuracy. This method also uses corn starch as a reference, incorporates a color blank, and removes unwanted particle contribution from sample results. To the best of our knowledge, this is the only industrial starch method that completely solubilizes the insoluble starch content in any sugar product.

Technical Abstract: An easy, rapid, and inexpensive method was developed to measure total, soluble, and insoluble starch in products at the factory and refinery, using microwave-assisted neutralization chemistry. The method was optimized using the previously developed USDA Starch Research method as a reference. Optimal acid and base combinations and concentrations plus microwave time and power were determined to completely solubilize an insoluble corn starch reference. The final method solubilizes <4,000 ppm insoluble starch in 2 min, has acceptable precision (7% CV, coefficient of variation), accuracy (=94%), uses a corn starch reference, and incorporates a color blank to remove contribution from natural colorants found in industrial samples. The method was validated using both simulated (5%) and factory products, i.e., sugarcane crusher juice (8% CV), clarified juice (12% CV), massecuite (2% CV), molasses (4% CV), syrup (2% CV), and eight raw sugars (8% CV). The USDA Starch Factory/Refinery and Research methods were very similar (R2 = 0.9994) with an overall mean difference of only ~6.5%.