Patent GB-716112-A (GB)
Title: Improvements in the manufacture of alginic materials
Inventor: MCDOWELL RICHARD HENRY
IPC: A23L29/256
Filed: 1950-10-18
Abstract: A process of preparing an alginate jelly comprises first mixing calcium alginate and a tri-basic alkali metal orthophosphate in the presence of such an amount of water that in the resulting reaction a paste is produced substantially consisting of tri-calcium phosphate, water and a soluble alginate, and after such reaction (and drying if desired) introducing the product into an aqueous medium and gelling by means of a free acid.  The tricalcium phosphate present is colloidally dispersed. The free acid may be provided by chemical reaction within the aqueous medium or by any other means, e.g. by diffusion of free acid into the aqueous medium which is to be gelled. A substance may be included to delay gelling, e.g. an excess of alkali metal orthophosphate may be employed in the initial reaction with the calcium alginate or alternatively an alkali metal alginate may be added after the reaction with the phosphate.  In examples sodium alginate containing colloidal calcium phosphate is prepared by mixing calcium alginate containing water with excess trisodium phosphate and the paste produced is dried and pulverized and a portion of the sodium alginate-calcium-phosphate preparation is mixed with gluconic delta lactone and the mixture is dissolved in water to give a solution which sets to a jelly (I); a similar jelly containing sugar is prepared (II); a portion of the sodium alginate-calcium phosphate preparation is dissolved in water and after the addition of ammonium phosphate and formaldehyde the mixture gradually sets to a jelly (III); a portion of the sodium alginate-calcium phosphate preparation, glucose and sucrose are dissolved in water and the mixture is heated and small portions are introduced into a solution of citric acid, sucrose and glucose in water, the extent to which gelling takes place being controlled by the time of immersion of the portions in the acid solution (IV); a sodium alginate-calcium phosphate preparation is obtained in a similar manner to that described above and to a part of the mixture sodium alginate is added and jellies are prepared on dissolving both preparations in water and adding gluconic delta lactone (V).  The added sodium alginate retards gel formation and syneresis.ALSO:A process of preparing an alginate jelly comprises first mixing calcium alginate and a tribasic alkali metal orthophosphate in the presence of such an amount of water that in the resulting reaction a paste is produced substantially consisting of tri-calcium phosphate, water and a soluble alginate and after such reaction and drying if desired, introducing the product into an aqueous medium and gelling by means of a free acid.  The tri-calcium phosphate present is colloidally dispersed.  The free acid may be provided within the aqueous medium or by any other means e.g. by diffusion of free acid into the aqueous medium which is to be gelled.  A substance may be included to delay gelling e.g. an excess alkali metal orthophosphate may be employed in the initial reaction with the calcium alginate or alternatively an alkali metal alginate may be added after the reaction with the phosphate.  In examples: sodium alginate containing colloidal calcium phosphate is prepared by mixing calcium alginate containing water with excess trisodium phosphate and the paste produced is dried and pulverized and a portion of the product is mixed with gluconic delta lactone and the mixture is dissolved in water which sets to a jelly (I); a similar jelly containing sugar is prepared (II); a portion of the sodium alginate-calcium phosphate preparation, glucose and sucrose are dissolved in water, the mixture is heated to expel air and small portions are introduced into a solution of citric acid, sucrose and glucose in water, the extent to which gelling takes place being controlled by the time of immersion of the portions in the acid solution. Suitably flavoured and coloured such jellies may be used in confectionery and baking (IV); a sodium alginate-calcium phosphate preparation is obtained in a similar manner to that described above and to a part of the mixture sodium alginate is added and jellies are obtained on dissolving both preparations in water and adding gluconic delta lactone (V).  The added sodium alginate retards gel formation and syneresis.