DCPD is a type of orthophosphate, a single phosphate group with two calcium atoms and two water molecules. This compound is a very stable acid salt which can be stored under suboptimal conditions without adverse effects on its leavening performance.
Incorporation into aqueous systems and hydration is the key to DCPD functionality in bakery batters. Especially, when heated to temperatures above 150°F (65°C). With these two conditions met, DCPD breaks down into phosphorus-containing acids and tricalcium phosphate. The acids formed then react with the bicarbonate and produce CO2.1
Leavening reaction of DCPD with baking soda:
CaHPO4·2H2O + NaHCO3 → Ca3(PO4)2 + Na2HPO4 + 8 H2O + 2CO2
During baking, a portion of DCPD decomposes into tricalcium phosphate and phosphoric acid, thus the basis for its good leavening acid characteristics. The chemical equation for this reaction is as follows:1
3CaHPO4 + Moisture + Heat → Ca3(PO4)2 + H3PO4 + 6H2O
DCPD is also used to adjust pH level of finished products (if no residual soda is present). Lowering pH of the product may affect crust and crumb color, however, it can also be beneficial in terms of shelf-life extension.
DCPD is synthetically produced from the reaction between calcium carbonate (hydrated lime) and phosphoric acid. The reaction requires carefully controlled reactants’ ratios and reaction conditions mainly pressure, pH and temperature, among others.
The neutralizing value (NV) of DCPD is 33, indicating that 100 grams of DCPD require 33 grams of sodium bicarbonate to achieve perfect neutralization and optimum CO2 release.1
Considerations when formulating DCPD in sweet baked goods:
DCPD holds a GRAS (generally recognized as safe) status in the United States.2