Patent GB-379081-A (GB)
Title: Improvements in or relating to the drying of liquids containing solids
IPC: A23L2/08
Filed: 1931-08-12
Abstract: Liquids containing solids, e.g. lemon, orange, and other fruit juices and whey, are dried by incorporating therein an irreversible colloid in the form of a weak gel co-extensive with the liquid and then drying to obtain a product containing the solids from the liquid and an irreversible colloid from the gel. The colloid may be a carbohydrate acid, such as pectic or alginic acid, or a salt thereof such as sodium pectate.  The gel may be produced in the liquid by adding thereto a carbohydrate acid salt and then acidifying; the precipitation of the gel may be assisted or promoted by adding a salt of a heavy metal, an alkaline-earth metal or magnesium to the liquid. The pictic acid or pectate may be obtained by treating calcium pectate with an acid, or an alkali metal or ammonium salt of an acid the calcium salt of which is insoluble; oxalates, tribasic phosphates and carbonates may be used.  The calcium pectate may also be dispersed by mixing it with an equal weight of sodium or potassium citrate or tartrate or disodium or dipotassium hydrogen phosphate and with water, and then heating.  The calcium pectate may be prepared by heating to 25-50 DEG  C. a pectin liquor, obtained for example by acid extraction of lemon pulp.  The liquor is then made slightly alkaline by adding a hydroxide of an alkaline earth or of magnesium, and about 0,5 gm. per litre of sodium hydroxide previously dissolved in a small amount of water is then added.  After agitation the curds obtained are strained off and are suspended in water which is then made acid by adding hydrochloric acid.  The precipitate is collected and washed free from hydrochloric acid and is said to be calcium pectate.ALSO:Calcium pectate is prepared by heating to 25-50 DEG  C. a pectin liquor, obtained for example by acid extraction of lemon pulp. The liquor is then made slightly alkaline by adding a hydroxide of an alkaline earth or of magnesium, and about 0,5 gm. per litre of sodium hydroxide previously dissolved in a small amount of water is then added.  After agitation the curds obtained are strained off and are suspended in water which is then made acid by adding hydrochloric acid.  The precipitate is collected and washed free from hydrochloric acid and is said to be calcium pectate. Sodium pectate may be obtained by treating calcium pectate with an acid, or an alkali metal or ammonium salt of an acid the calcium salt of which is insoluble; oxalates, tribasic phosphates and carbonates may be used.  The calcium pectate may also be dispersed by mixing it with an equal weight of sodium or potassium citrate or tartrate or disodium or dipotassium hydrogen phosphate and with water, and then heating.ALSO:Liquids containing solids, e.g. lemon, orange, and other fruit juices and whey, are dried by incorporating therein an irreversible colloid in the form of a weak gel coextensive with the liquid and then drying to obtain a product containing the solids from the liquid and an irreversible colloid from the gel. The colloid may be a carbohydrate acid, such as pectic or alginic acid, or a salt thereof such as sodium pectate.  The gel may be produced in the liquid by adding thereto a carbohydrate acid salt and then acidifying; the precipitation of the gel may be assisted or promoted by adding a salt of a heavy metal, an alkaline earth metal or magnesium to the liquid.  Sodium pectate may be obtained by treating calcium pectate with an acid, or an alkali metal or ammonium salt of an acid the calcium salt of which is insoluble; oxalates, tribasic phosphates, and carbonates may be used.  The calcium pectate may also be dispersed by mixing it with an equal weight of sodium or potassium citrate or tartrate or disodium or dipotassium hydrogen phosphate and with water, and then heating. The preparation of calcium pectate is described.