Pressurized solvent extraction of pure food grade starch

A commercial pressurized solvent extractor was used to remove lipid and non-lipid material from cornstarch using n-propanol/water and ethanol/water mixtures. Yields and chemical composition of the extract fractions were determined. Cornstarch samples were characterized using pasting properties and shear storage modulus measurements. The n-propanol/water extracted slightly higher amounts of both lipids and non-lipids. The lipid fractions contained mostly linoleic, palmitic and oleic free fatty acids. The non-lipid fraction contained mostly protein in the form of zein. The extracted starch had lower peak and setback viscosities than did the unextracted starch. The starch extracted with n-propanol/water had the lowest shear storage modulus values. Conversely, the samples extracted with ethanol/water had the highest shear storage modulus values. It is hypothesized that low amounts of zein present in conjunction with the starch is responsible for this observed effect.