ARS | Publication request: Preparation and Properties of Water-Soluble Starch Acetates

Submitted to: Meeting Abstract
Publication Type: Abstract
Publication Acceptance Date: January 20, 2004
Publication Date: March 28, 2004
Citation: Shogren, R.L. 2004. Preparation and properties of water-soluble starch acetates. American Chemical Society, March 28-April 1, 2004, Anaheim, CA. 2004 CDROM.

Technical Abstract: Starch acetates of degree of substitution (DS) 0-1.5 were prepared by heating dry corn starch, acetic acid and acetic anhydride in sealed 60 ul vessels at 180 degree C for 5 minutes. These reactions appeared to be homogeneous (clear) and proceeded to completion without added catalyst. Starch acetates of DS 0.5-1.0 gave clear solutions in cold water while starch acetates of DS 0.25-0.5 were greater than 90% soluble. Reactions were scaled up using a stirred microwave reactor. The intrinsic viscosity of a deacylated starch acetate of DS 0.73 in 1 M KOH was 0.70 dl/g compared to a literature value for native corn starch of 1.6 dl/g, indicating some hydrolysis of the starch backbone occurred during heating. Acetylation occurred preferentially at the C6 position (70%), based on 13C NMR results. Contact angles of starch acetate solutions on polymer films were significantly lower than pure water. Thus, the above is a rapid and efficient route to simultaneously acetylate and gelatinize starch and applications as coatings, sizes, and emulsifiers could be contemplated.