Comparison of the effects of critical fluid and reflux-extracted techniques on cornstarch pasting properties

Critical fluid extraction of native lipids from cornstarch using 75/25 (v/v) ethanol/water as the solvent removed over 99% of the native lipid. The percentage of native lipid extracted was altered by changing the solvent/starch ratio. The pasting properties and shear storage modulus of a defatted, critical fluid-extracted sample differed from those of a sample defatted by refluxing with 75/25 (v/v) n-propanol/water, although both samples contained only trace amounts of residual native lipid. The percent soluble starch in the lipid-extracted starches was higher than that of the control starch, which was expected since extraction of native lipids reduced the amount of lipid-complexed amylose within the starch granule and enabled more intragranular amylose to be leached out. This study describes a convenient, non-toxic process for extracting native lipids from cornstarch, and the altered pasting and gelling properties of these extracted starches could result in new end-use applications.