Sodium citrate is a food additive which is mainly used in cough syrups and for neutralizing acids in urine. It is also used as a pharmaceutical aid and as a food additive. It can also be used as a laboratory reagent and as a chemical for treating water. This chemical is commonly found as trisodium citrate which is used as an emulsifier, acidity regulator, calcium sequestrant, and preservative. This sodium citric acid has wide usage because relatively it has the simplest chemistry.
Origin of sodium citrate
Basically, there are 3 types of sodium citrate –
- Monosodium citrate
- Disodium citrate
- Trisodium citrate
Trisodium is the most commonly used variant for food products. In order to get the sodium citric acid you have to remove the H+ portion of the citric acid and replace it with Na+ ions. Practically, this chemical has been a very important base agent in chemistry labs. The sodium citric acid requires more acid than normal to reduce pH of any solution due to this tendency it makes easier to make adjustments in acidity.
Other than being a buffering agent, this chemical also acts as a sequestering agent that means that it can bind with other ions that are present in the solution. Especially with cheese because it consists of calcium ions which are replaced with sodium ions in order to change its structure and expose it to oil and water-loving ends.
Its sequestering abilities play a vital role in molecular gastronomy. There are some agents that forms gel in the presence of calcium, but these ions make difficult the process of hydration of hydrocolloids which is required to form a gel. Sequestrants like sodium citric acid can be used to bind these ions and enable the hydration process properly.
Sometimes calcium reacts with hydrocolloids forming a thin layer which, however, is likely to occur naturally in tap water. So it can be used to reduce calcium and avoid early gelation. It is also particularly used for this process as they can increase the pH level slightly which can help in spherification process.
It is basically used as an emulsifier which is used to make dairy products like cheese because basically it can prevent a dairy product from becoming stale for many days in comparison to other solutions. Sodium citric acid is also used as food additives and found as flavoring agents in many products like ice-creams, wine, beverages, milk powders, sweets, and jams.
Temperature – It is soluble in water at any temperature but the amount of solubility changes with temperature.
Texture- It does not have a structure of its own, but it plays a vital role in changing structures of various elements like turning a cheese creamy.
Appearance – It is solid as white granules, which is much like salt.
Flavor release- N/A
Freeze/ Thaw stable- N/A
Interaction and tolerance:
pH Tolerance– This chemical has an ability to slightly change the pH level of a solution when added in it. As a result, it is very important to make a solution more resistant to change in pH levels.
Synergies with other ingredients- It is important component used for spherification process. In liquid solutions sometimes it is likely to have an increase in calcium which leads to clumping of hydrocolloids. But here, sodium citric acid is used to trap extra calcium allowing the hydrocolloids to hydrate properly.
How to use sodium citrate?
It is quite difficult to determine an exact concentration range for the practical use of this chemical because it depends on the other ingredients that are used. It should be used moderately because it’s both salty and sour which can affect the flavors of your preparation. If not sure, always consult specialist!
As an emulsifier, it is advised to use 4% of the mass of the product. For making cheese slices, 3.3% of sodium citric acid should be used with 1.5% iota carrageenan and 0.5% kappa carrageenan.
As a sequestrant, 0.7% to 0.4% can be used depending upon the liquid and concentration of hydrocolloids. In spherification, the amount of sodium citric acid depends on the amount of calcium ions present in a liquid.
So, these were some of the important facts about sodium citric acid that one should always keep in mind while dealing with it.
Written by Daniel Clark