title: Development of an analytical method to measure insoluble and soluble starch in sugarcane and sweet sorghum products.
abstract: A rapid research method using microwave-assisted probe ultrasonication was developed to quantify total, insoluble, and soluble starch in various sugar crop products. Several variables affecting starch solubilisation were evaluated, (1) heating method, (2) boiling time, (3) probe ultrasonication time, (4) water loss, (5) concentration, (6) sample colour, and (7) sample. The optimised method solubilises < 40,000 ppm insoluble starch with microwave-assisted sonication in 6 min, has acceptable precision (<6% CV), accuracy (⩾ 95%), uses a corn starch reference, and incorporates a colour blank to remove contribution from natural colourants found in industrial samples. This method was validated using factory samples and found applicable to sugarcane and sweet sorghum bagasse (3% CV), mixed juices (2%), massecuites (4%), molasses (7%), and raw sugars (12%), 100% satisfactory performance z-scores were also obtained. Total starch values obtained with this method were significantly higher than those measured using other methods presently accepted by the sugar industry.
authors.affiliation: Southern Regional Research Center, Agricultural Research Services, U.S. Department of Agriculture, 1100 Robert E. Lee Blvd., New Orleans, LA, USA. Electronic address: Marsha.Cole@ars.usda.gov.
authors.forename: Marsha R
authors.initials: MR
authors.lastname: Cole
authors.affiliation: Southern Regional Research Center, Agricultural Research Services, U.S. Department of Agriculture, 1100 Robert E. Lee Blvd., New Orleans, LA, USA.
authors.forename: Gillian
authors.initials: G
authors.lastname: Eggleston
authors.affiliation: Department of Food Science, Agroparistech, Paris, France.
authors.forename: Audrey
authors.initials: A
authors.lastname: Gilbert
authors.affiliation: Southern Regional Research Center, Agricultural Research Services, U.S. Department of Agriculture, 1100 Robert E. Lee Blvd., New Orleans, LA, USA.
authors.forename: Yoo Jin
authors.initials: YJ
authors.lastname: Chung
mesh_terms: D031786:Saccharum / Q000737:chemistry*; D045868:Sorghum / Q000737:chemistry*; D013213:Starch / Q000032:analysis / Q000737:chemistry*
chemical_list: D013213:Starch
keywords: Insoluble starch; Microwave; Probe ultrasonication; Soluble starch; Starch solubilisation; Sugar products; Sugarcane; Sweet sorghum