PREPARATION AND PROPERTIES OF WHEAT AND CORN STARCH MALTODEXTRINS WITH A LOW DEXTROSE EQUIVALENT

Wheat and corn maltodextrins (W-MD 8 and C-MD 8) with dextrose equival ent (DE) 2-3 were prepared by heterogeneous bacterial alpha-amylase di gestion of a 15% starch paste at 95 degrees C for 8 min followed by co oling and spray-drying. Gels of the two maltodextrins appeared opaque with a glossy surface and melted reversibly at approximate to 65 degre es C. Scanning electron micrographs showed that the products were divi ded finely and had few large remnants of starch granules. The fine gra nulation of W-MD 8 and C-MD 8 caused some clumping in cold water; homo geneous solutions were achieved with vigorous stirring at 90 degrees C . Size-exclusion chromatograms showed that the two products contained similar broad, molecular-weight distributions of saccharides. A commer cial potato maltodextrin marketed as a fat-replacer contained fewer sh ort-length molecules when compared to W-MD 8 and C-MD 8, whereas a com mercial corn maltodextrin fat-replacer contained more. High-performanc e anion-exchange chromatography with pulsed-amperometric detection sho wed that all four maltodextrins contained only linear maltosaccharides between DP 2 and 25, with elevated levels of maltotriose and maltohex aose. The new wheat and corn maltodextrins contained O.6-1.0% lipids a nd became rancid when stored at >30 degrees C. The rancidity developme nt in W-MD 8 was eliminated either by alkali treatment of starting sta rch or by charcoal treatment of the warm hydrolyzate.