Acid Sodium Pyrophosphate

Table 6 Hsts the leavening acids and the corresponding rates of reaction. The leavening acids most frequently used iaclude potassium acid tartrate, sodium aluminum sulfate, 5-gluconolactone, and ortho- and pyrophosphates. The phosphates iaclude calcium phosphate [7758-23-8] CaHPO, sodium aluminum phosphate, and sodium acid pyrophosphate (66).

There are occasions where the mud pH must be lowered such as after drilling fresh cement or overtreatment by one of the alkaline materials discussed. Organic acids that have been used for this purpose include acetic acid [64-19-7], citric acid [77-92-9], and oxaHc acid [144-62-7]. These materials are used infrequently. Inorganic additives used to lower pH levels include sodium bicarbonate [144-55-8] and sodium acid pyrophosphate [7758-16-9] (SAPP). Of the two, sodium bicarbonate is used the most by far. 

Sodium Pyrophosphates. Known pyrophosphate compounds in the Na20—H2O—P20 system are given in Table 10. Commercially important sodium pyrophosphates include tetrasodium pyrophosphate (TSPP), Na4P20y, and disodium pyrophosphate, Na2H2P20y, commonly referred to as sodium acid pyrophosphate (SAPP). These are prepared industrially by thermal dehydration of disodium and monosodium orthophosphate, respectively. Tetrasodium pyrophosphate exists in five crystalline modifications, only one of which is stable at room temperature. 

Fig. 8. Solubihties of sodium acid pyrophosphate and tetrasodium pyrophosphate.

A number of acidic phosphates which vary in their rate of reaction are available for use in a wide variety of bakery appHcations. These acids, which include monocalcium phosphate, sodium aluminum phosphate, and sodium acid pyrophosphate, release carbon dioxide at a controlled rate to give a certain fraction prior to baking the remaining fraction is released at a specific time during baking. Controlled releasing of carbon dioxide at the time it is needed can also be achieved by a mixture of different types of leavening acids. 

Chemical Designations - Synonyms Sodium phosphate is generic term and includes the following (1) monosodium phosphate (MSP sodium phospWe, monobasic), (2) disodium phosphate (DSP sodium phosphate dibasic), (3) trisodium phosphate (TSP sodium phosphate, tribasic), (4) sodium acid pyrophosphate (ASPP SAPP disodium pyrophosphate (TSPP), (6) sodium metaphosphate (insoluble sodium metaphosphate), (7) sodium trimetaphosphate, and (9) sodium tripolyphosphate (STPP TPP) Chemical Formula (1) NaHjPO (2) Na HPO (3) NajPO (4) Na H P O, (5) Na P O, (6) (NaPOj) (7) (NaP03)3 (8) (NaP03) NaO (9) Na,P30,o. 

E450 disodium dihydrogen diphosphate (sodium acid pyrophosphate)... 

Monocalcium phosphate monohydrate reacts almost as quickly as cream of tartar (potassium acid tartrate). Anhydrous monocalcium phosphate has four-fifths of the reactivity. At ambient temperatures dicalcium phosphate dihydrate, sodium aluminium phosphate and some grades of sodium acid pyrophosphate are essentially unreactive. 

The reaction rate of sodium acid pyrophosphate can be controlled by adding calcium ions. While this process happens anyway in the presence of skim milk solids, manufacturers deliberately add calcium ions to sodium acid pyrophosphate to give grades with slower dissolution. 

Sodium acetylide, 1 179, 22 765 Sodium acid pyrophosphate (SAPP),... 

Anhydrous salt white crystalline powder slightly hygroscopic forms sodium acid pyrophosphate, Na2H2P20 on heating above 225°C and sodium metaphosphate (NaPOsln at about 350 to 400°C very soluble in water, aqueous solution acidic. 

Sodium acid pyrophosphate Sodium citrate Sodium diacetale Sodium gluconate... 

Prepared bi.scitil mixes made of flour, shortening, and salt usually contain 50-5057 lnnnncaleium phosphate I anhydrous) and 50-71)97 sodium aluminum phusphale or sodium acid pyrophosphate. Sell-rising flours and corn meals usually contain flour or com meal, salt, soda, and leavening acid. Usually used in these products are combinations of sodium aluminum phosphate and monncalciuin phosphate (anhydrous). 

Other possible builder salts include tetrapotas-sium pyrophosphate, sodium trimetaphosphate, trisodium and tripotassium phosphates, and sodium acid pyrophosphates. Significant literature reviews cover this subject in great detail.24 25... 

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