GB713899A - Process of fractionating starch - Google Patents

Abstract

In fractionating starch into amylose and amylopectin, the starch is dissolved at elevated temperature in an aqueous solvent and the solution is cooled, amylose being precipitated by adding to the solvent or to the solution, before or after cooling, an amount of an organic medium substantially below that required to saturate the solvent when the medium is soluble therein, or an amount giving a concentration not exceeding 12 per cent. by weight when the medium is miscible therewith. The amylose may be precipitated at 20-35 DEG C. from a solution having a starch concentration not exceeding 1.5 per cent., or at 45-50 DEG C. from a solution containing not more than 5 per cent. starch. The organic medium may be butyl alcohol, amyl alcohol, sec-n-octyl alcohol, cyclohexanol, methyl-cyclohexanol, benzyl alcohol phenol, o, m-, p-cresol, carvacrol, o-, p-chlorophenol, o-, p-bromophenol, o-, p-nitrophenol, thymol, terpineol, aniline, methyl ethyl ketone, isopropyl ketone, isoamyl ketone, chloral hydrate, nitropropane, nitrobenzene, nitronaphthalene, ethylene chloride, quinoline, pyridine, dioxane, tri-nitro-chloro-methane, butyric acid or mixtures thereof. Sec.-n-octyl alcohol may be used at a volume concentration of about 0.035 per cent., isopentanol at a concentration of 2-2.5 per cent. and di-isopropyl ketone at a concentration of about 6 per cent. The precipitated amylose may be separated from the liquid in a centrifuge. Amylopectin may be precipitated from the liquid by cooling it to about 0 DEG C. or by adding more of the organic medium or methyl or ethyl alcohol and then cooling the mixture to about 3 DEG C. The amylopectin may be centrifugally separated from the remaining liquor which may be re-used as a solvent for starch. Specification 590,750 is referred to.