Inventions on phosphates for chemical leavening

Baking powders contain leavening acids that activate gas-releasing agents such as sodium bicarbonate. This is a review of the patent literature on phosphate-based leavening acids developed between 1856 and 2019. Overall, 174 patented inventions were found on 28 phosphate-based compounds, which corresponded to more than half of the inventions disclosed on leavening acids. Inventors had a strong interest in monocalcium phosphate, sodium acid pyrophosphate and, to a lesser extent, sodium aluminium phosphate and miscellaneous acid phosphates. As cheap alternatives to tartrates, most early phosphate-based leavening acids were difficult to keep because they had a high affinity for moisture and tended to react prematurely with gas-releasing agents in baking powders. The evolution of phosphates in chemical leavening reflected changes in the consumption of bakery foods, especially in the United States where chemical leavening has been very popular for food preparations like prepared flours, ready-to-use bakery mixes and refrigerated doughs. Sodium-free phosphates are solutions to reduce salt intake in food. Alternatives to phosphates are searched due to potential health issues.