| 摘要 |
A cold-water swelling alkali metal starch phosphate containing from 1 per cent to about 5 per cent bound phosphorus based on the weight of the starch and between about 1.0 and 1.75 atoms of alkali metal per atom of bound phosphorus and which is suitable for preparing a pudding (see Group VI) is obtained by commingling ungelatinized starch with an aqueous solution containing an orthophosphate salt of an alkali metal and having a pH between about 4 and about 7, removing unabsorbed liquid from the treated starch at a temperature below the gelatinization point thereof and heating the treated starch at a temperature between about 120 DEG and about 175 DEG C. until the reaction has proceeded to substantial completion. The alkali metal phosphate may be a single phosphate, e.g. of sodium, potassium or lithium, or a combination of alkali metal phosphates. Thus, monosodium phosphate monohydrate and disodium phosphate dodecahydrate may be combined in an aqueous solution in such proportion that the resulting solution has a pH between about 4 and about 7. The phosphate salts may be formed in situ in the solution, e.g. by dissolving a basic phosphate such as trisodium phosphate in water and adjusting the pH of the solution with phosphoric acid or monosodium phosphate to between about 4 and about 7. Alternatively, an aqueous solution of an acidic sodium, potassium or lithium phosphate may be neutralized with sodium-, potassium- or lithium-hydroxide. The heating of the treated starch with the alkali metal orthophosphate until the reaction is substantially complete is generally effected for from 1 to 15 hours, and usually for about 4 hours at between 140 DEG and 170 DEG C., and may be carried out either at atmospheric pressure or under vacuum. The swollen starch granules resulting from the treatment with the phosphate solution may be separated from the solution by filtration and excess surface moisture is preferably removed before the final heating step, e.g. by drying in air or heating at below about 45 DEG C. The starch used may be a root starch such as tapioca starch or potato starch or a cereal starch such as corn starch or wheat starch. In examples: (1) monosodium phosphate monohydrate is dissolved in water to give a pH of about 4.3 and wheat starch is added to give a slurry which is stirred and then filtered, the filter cake being dried in air and then heated at about 140 DEG C. for about 3 hours to give a cold-water swelling alkali metal starch phosphate; (2) and (3) mixtures of monosodium phosphate monohydrate and disodium phosphate dodecahydrate in different proportions are dissolved in water to give a pH of about 6.1 and about 6.5 respectively, wheat starch is then added and the procedure of (1) is repeated except that the final heating step is for 5 hours at about 160 DEG C. Specification 812,339 is referred to.ALSO:A composition suitable for preparing a pudding comprises sugar, flavouring, and a cold-water swelling alkali metal starch phosphate containing 1-5 per cent of bound phosphorus based on the weight of the starch and between 1.0 and 1.75 atoms of alkali metal per atom of bound phosphorus obtainable by commingling ungelatinized starch with an aqueous solution containing an orthophosphate salt of an alkali metal and of pH 4-7, removing unabsorbed liquid from the treated starch at a temperature below the gelatinization point, and heating the treated starch at a temperature between 120 DEG C. and 175 DEG C. (see Group IV (b)). The starch used to form the alkali metal starch phosphate may be a root starch such as tapioca starch or potato starch or a cereal starch such as corn starch or wheat starch. The alkali metal orthophosphate may be a single phosphate of sodium, potassium, or lithium, or a combination of such phosphates, e.g. a mixture of monosodium phosphate monohydrate and disodium phosphate dodecahydrate may be used. The alkali metal starch phosphate is preferably washed with an aqueous solution of a water-soluble alcohol, e.g. methanol or ethanol, before use in the pudding composition. In examples: (1) a pudding mix comprising sodium starch phosphate, Irish moss extract, tetrasodium pyrophosphate, calcium acetate, sodium chloride, can sugar, and vanilla flavouring is mixed with cold whole milk and the mixture is then poured into bowls and allowed to chill to form a firm, smooth-textured pudding which does not separate or weep after standing for two days; (2) a mixture of two sodium starch phosphate products is mixed with cane sugar and cocoa and added to cold whole milk and the mixture allowed to stand to form a firm, smooth pudding which sets rapidly and does not weep or separate afterstanding for two days. The sodium starch phosphate used in (1) is obtained from monosodium phosphate monohydrate and wheat starch and contains 1 per cent of bound phosphorus and 1 atom of sodium per atom of bound phosphorus. The sodium starch phosphates used in (2) are formed from wheat starch and mixtures of monosodium phosphate monohydrate and disodium phosphate dodecahydrate in different proportions, one of the sodium starch phosphate products contains 5.1 per cent bound phosphorus and about 1.5 atoms of sodium per atom of bound phosphorus and the other contains 3.7 per cent bound phosphorus and about 1.66 atoms of sodium per atom of bound phosphorus. Specification 812,339 is referred to. |
