What is Calcium Peroxide?
Calcium peroxide (CaO2) is a fast oxidising agent used as a processing aid or dough conditioner in the production of yeast-leavened bakery products. This ingredient is necessary when gluten needs to be reinforced because of a non-optimal flour quality. The action of calcium peroxide ceases during baking, where it breaks down to calcium and oxygen at high temperatures.
Calcium peroxide also serves the following purposes:
- Increases the water absorption of the dough
- Strengthen the gluten structure by encouraging disulphide bonding between gliadins and glutenins
- Produces a dry and elastic dough with improved handling or machinability, which is very useful in the make-up stage
Calcium peroxide is chemically synthesized from calcium salt and sodium peroxide.
Calcium peroxide is made by the addition of hydrogen peroxide to slaked lime (calcium hydroxide),
then dried to form a powder:1
Ca(OH)2 + H2O2 → CaO2 + 2 H2O
Once it comes in contact with water, calcium peroxide breaks down. This ingredient works by fixing the oxygen incorporated into the dough during mixing. This triggers a chemical process that reinforces the bonding of protein chains by creating disulfide bonds (cross-linking) from sulfhydryl groups of proteins, leading to a stronger gluten structure.
The recommended usage level is usually 20–35 ppm.2 However, the amount scaled should be calculated or adjusted according to the process and flour characteristics. The following are some recommendations when using calcium peroxide:
- To avoid any potentially negative effect on dough extensibility, it is very important to precisely control the amount of calcium peroxide added.
- If dosing in a tablet form, special care must be taken during scaling so as not to violate regulation limits, nor compromise the quality of the dough through high or low dosing. The bakery should know the concentration of oxidizing agent per tablet, as this will determine the number of tablets to use.
- Calcium peroxide is especially useful in no-time dough processes, where there is no pre-fermentation that promotes natural oxidation and maturation.
- Calcium peroxide is used at lower levels, or even not used in pre-ferment production systems, since the elastic/liquid sponge has already been matured during first fermentation step (the acid environment strengthen the protein bonds).
- As a rule of thumb, the weaker the flour (i.e., the lower its protein content), the more calcium peroxide is needed for the dough to properly develop.3
This type of oxidizing agent is also useful in the production of frozen bakery products. Here, the calcium peroxide acts as strengthener of the dough prior to the freezing process. By improving the quality of the gluten structure, the product can better retain water during thawing.3
Bakeries should be careful when handling this additive due to its comburent nature, as it supports combustion. If stored at a fixed location in the bakery, calcium peroxide should be properly sealed or contained in a closed vessel in case of large amounts in powder form, or it should be bought in small presentations of less than 1 Kg that can be used for a few batches. Storage facilities should have ventilation systems that allow sufficient air changes per hour.
The FDA provides specific guidelines for calcium peroxide under CFR § 136.110: “Requirements for Specific Standardized Bakery Products.” This rule establishes that amounts of calcium peroxide, alone or combined with two or more oxidizing agents, cannot exceed 75 ppm by weight of flour used.4
- Solvay – Advanced Materials and Specialty Chemicals. https://www.solvay.us/en/index.html. Accessed 10 April 2018.
- Wieser, H. “The Use of Redox Agents in Breadmaking.” Breadmaking: Improving Quality, Woodhead Publishing Limited, 2012, pp. 463.
- Suas, M. “Advanced Flour Technology and Dough Conditioners.” Advanced Bread and Pastry: A Professional Approach, Delmar, Cengage Learning, 2009, pp. 153–155.
- U.S. Food and Drug Administration. “21 CFR 136 – Bakery Products.” 1 Apr. 2017, https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?CFRPart=136.