Patent GB-620989-A (GB)
Title: Foam-producing composition and method of making the same
IPC: A62D1/02
Filed: 1947-02-07
Abstract: A foam-producing material is prepared by partial hydrolysis of a substantially starch-free zein-containing product with an alkaline earth hydroxide in aqueous medium at elevated temperature, removal of any insoluble alkaline earth soap from the hot solution, addition of ammonium sulphate and boiling to yield a substantially neutral product, precipitate alkaline earth sulphate, and concentrate the solution, removal of precipitate, and addition of a foam-stabilizing water-soluble salt either before or after removal of precipitate. While pure zein is a suitable starting material, commercial starch-free maize glutens are preferred and are freed from oil, preferably during the hydrolysis which converts it into alkaline earth soap.  The hydrolysis is preferably effected by boiling, under pressure if desired, with milk of lime, ordinarily in a ratio of not less than 1 : 10 by weight, although strontium and barium hydroxides are suitable.  A sample taken towards the end of the reaction, after cooling, desirably has a pH of 9.5-11.5.  After neutralizing and concentrating, it should be 6.5-8.0.  The concentrate generally has a viscosity of 22-70 centipoises at an S.G. of 1.13 at 70 DEG  F., varying with the time of hydrolysis.  The stabilizing salt, such as a salt of iron, aluminium or chromium, is generally added in an amount of 1.5-2.0 per cent of the product.  Freezing point depressants such as glycol, urea or glycerol, generally about 5-10 per cent, and preservatives such as sodium silicofluoride or salts of quaternary bases, generally about 0.1 per cent, may also be added.  In examples, a commercial starch-free gluten is boiled with lime and water for 5 hrs.  After the filtering, neutralizing, and concentrating to S.G. 1.13, ferrous sulphate, glycol or urea, and sodium silicofluoride are added to the hot solution which is filtered, cooled and diluted if necessary to give a viscosity of 40 centipoises at 70 DEG  F.ALSO:A foam-producing material is prepared by partial hydrolysis of a substantially starch-free zein-containing product with an alkaline earth hydroxide in aqueous medium at elevated temperature, removal of any insoluble alkaline earth soap from the hot solution, addition of ammonium sulphate and boiling to yield a substantially neutral product, precipitate alkaline earth sulphate, and concentrate the solution, removal of precipitate and addition of a foam-stabilizing water-soluble salt either before or after removal of precipitate. While pure zein is a suitable starting material, commercial starch-free maize glutens are preferred and are freed from oil, preferably during the hydrolysis which converts it into alkaline earth soap.  The hydrolysis is preferably effected by boiling, under pressure if desired, with milk of lime, ordinarily in a ratio of not less than 1 : 10 by weight, although strontium and barium hydroxides are suitable.  A sample taken towards the end of the reaction, after cooling, desirably has a pH of 9.5-11.5.  After neutralizing and concentrating, it should be 6.5-8.0.  The concentrate generally has a viscosity of 22-70 centipoises at an S.G. of 1.13 at 70 DEG  F., varying with the time of hydrolysis.  The stabilizing salt, such as a salt of iron, aluminium or chromium, is generally added in an amount of 1.5-2.0 per cent of the product.  Freezing point-depressants such as glycol, urea or glycerol, generally about 5-10 per cent, and preservatives such as sodium silicofluoride or salts of quaternary bases, generally about 0.1 per cent, may also be added.  In examples, a commercial starch-free gluten is boiled with lime and water for 5 hours. After the filtering, neutralizing, and concentrating to S.G. 1.13, ferrous sulphate, glycol or urea and sodium silicofluoride are added to the hot solution which is filtered, cooled and diluted if necessary to give a viscosity of 40 centipoises at 70 DEG  F.