GB688291A - Starch product of improved properties and method of making the same - Google Patents

Abstract

Ungelatinized starch derivatives are made by reacting raw starch in the presence of alkali, under conditions which avoid gelatinization, with chlormethyl-isothionic acid, a ,b -unsaturated olefin sulphonic acids, benzoyl chloride p-sulphonic acid or salts thereof or by reacting, under the same conditions, sulphurous acid or a bisulphite with an unsaturated starch derivative having an ethylenic double bond of the formula <FORM:0688291/IV (b)/1> wherein R is <FORM:0688291/IV (b)/2> or -OCH2O- and, if both R2 and R3 are hydrogen, R1 is a member of the group formyl, cyano, carboxy, carbalkoxy or carbalkyl and, if either R2 or R3 is a member of the group formyl, cyano, carboxy, alkyl, aryl or substituted alkyl or aryl radicals, R1 is hydrogen or a member of the second group. The starch may be from any source and includes acid hydrolysis, oxidation or other conversion products. The derivatives have use as adhesives, thickeners for food, and sizes. Unsaturated starch derivatives which are reacted with bisulphites include esters made by treating starch in aqueous suspension with alkali and anhydrides of such acids as maleic, citraconic, itaconic, and crotonic. Bisulphite addition may take place at temperatures below that of gelatinization in aqueous suspension or while refluxing in ethanol or other non-aqueous medium. Reaction of raw starch with the compounds containing a sulphonic acid group and an ester or ether-forming group requires considerable alkali concentrations and, to avoid gelatinization, the starch may be suspended in concentrated sodium sulphate solution. The unsaturated starch derivatives treated may contain 1 unsaturated radical per 15-140 anhydroglucose units. Where raw starch is treated, 1 sulphonic group may also be introduced per 15-140 anhydroglucose units. The amount of bisulphite used is preferably 7 or 4 times the theoretical at room temperature or 50 DEG C. respectively with a treatment time of 4 hours. Examples describe the treatment of a corn starch ester of maleic acid, tapioca starch ester of crotonic or itaconic acid, potato starch ester of citraconic acid, and corn starch ether of 1-hydroxy - 3 - carboxy - propene - 2,3 with sodium, potassium or ammonium bisulphite, and of unmodified starch with sodium benzyl chloride p-sulphonate or sodium chlormethylisothionate.ALSO:Sizes for paper and textiles, paper beater sizes, adhesives and laundry starches comprise ungelatinized starch derivatives containing a sulphonic acid group, made by reacting raw starch with compounds containing such a group and capable of etherifying or esterifying the starch or by reacting sulphurous acid or a bisulphite with an unsaturated starch derivative, (see Group IV (b)). The starch may be from any source and includes acid hydrolysis, oxidation or other conversion products. The products have increased water absorption, and yield cooked pastes of greater clarity and resistance to gelling. The gelatinization temperature is lower. Examples describe the treatment of a corn starch ester of maleic acid, tapioca starch ester of crotonic or itaconic acid, potato starch ester of citraconic acid, and corn starch ether of 1-hydroxy-3-carboxy-propene-2,3 with sodium, potassium or ammonium bisulphite, and of unmodified starch with sodium benzyl chloride p-sulphonate or sodium chlormethylisethionate.ALSO:Ungelatinized starch derivatives used for food thickening, pie fillings, and salad dressings, and containing a sulphonic acid group are made by reacting raw starch with compounds containing such a group and capable of etherifying or esterifying the starch or by reacting sulphurous acid or a bisulphite with an unsaturated starch derivative (see Group IV (b)). The starch may be from any source and includes acid hydrolysis, oxidation or other conversion products. The products have increased water absorption, and yield cooked pastes of greater clarity and resistance to gelling and the action of acids and salts. The gelatinization temperature is lower. Examples describe the treatment of a corn starch ester of maleic acid, tapioca starch ester of crotonic or itaconic acid, potato starch ester of citraconic acid, and corn starch ether of 1-hydroxy-3-carboxy-propene-2,3 with sodium, potassium or ammonium bisulphite, and of unmodified starch with sodium benzyl chloride p-sulphonate or sodium chlormethylisethionate.