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Preparation and Properties of Wheat and Corn Starch Maltodextrins with a Low Dextrose Equivalent¹

¹Contribution No. 97-106J. Kansas Agricultural Experiment Station, Manhattan, KS. ²Dept. Food Science and Human Nutrition, Iowa State University, Ames, IA 50010. ³Dept. Grain Science & Industry, Kansas State University, Manhattan, KS 66506-2201.

Wheat and corn maltodextrins (W-MD 8 and C-MD 8) with dextrose equivalent (DE) 2–3 were prepared by heterogeneous bacterial α-amylase digestion of a 15% starch paste at 95°C for 8 min followed by cooling and spray-drying. Gels of the two maltodextrins appeared opaque with a glossy surface and melted reversibly at ≈65°C. Scanning electron micrographs showed that the products were divided finely and had few large remnants of starch granules. The fine granulation of W-MD 8 and C-MD 8 caused some clumping in cold water; homogeneous solutions were achieved with vigorous stirring at 90°C. Size-exclusion chromatograms showed that the two products contained similar broad, molecular-weight distributions of saccharides. A commercial potato maltodextrin marketed as a fat-replacer contained fewer short-length molecules when compared to W-MD 8 and C-MD 8, whereas a commercial corn maltodextrin fatreplacer contained more. High-performance anion-exchange chromatography with pulsed-amperometric detection showed that all four maltodextrins contained only linear maltosaccharides between DP 2 and 25, with elevated levels of maltotriose and maltohexaose. The new wheat and corn maltodextrins contained 0.6–1.0% lipids and became rancid when stored at >30°C. The rancidity development in W-MD 8 was eliminated either by alkali treatment of starting starch or by charcoal treatment of the warm hydrolyzate.