Sodium bicarbonate (NaHCO₃), also known as baking soda or sodium hydrogenocarbonate, is a white basic mineral powder and is commonly used as an ingredient in the food market. Not a new ingredient to the industry, it is authorised and registered as a food ingredient with the reference E500ii in Europe.

The ingredient is used largely in the bakery and confectionery industries as it has several advantageous properties. For example, it can be used as leavening agent, pH buffer, and effervescent agent—more on these will be discussed here.

HOW IS IT PREPARED?

Companies such as Novabay manufacture sodium bicarbonate with the use of a high purity soda ash. The ingredient is obtained via crystallisation through the carbonation of an aqueous high purity soda ash solution. The carbon dioxide gas used for the carbonation is a by-product of a solvent factory near Novabays factory, and its purity is strictly controlled.

SODIUM BICARBonATE USED AS LEAVENING AGENT

To give volume to bakery formulations like cakes, crackers and wafers, a baking powder is mandatory. A baking powder contains three types of ingredients:

• One basic agent: Sodium Bicarbonate
• One acid agent for instance Sodium Acid Pyrophosphate (SAPP) or citric acid
• One bulking agent for instance maize starch

The standard proportions are 30/40/30 percent weight (NaHCO₃/SAPP/starch). The leavening action is given by the release of CO2 thanks to two chemical reactions.

Reaction 2a has a higher CO2 yield than Reaction 2b. Reaction 2a begins when the reagents dissolve during the preparation of the paste of the formulation. Reaction 2b begins when the preparation is heated.

The rate of Reaction 2a depends on several parameters, such as the choice of the acid agent and the specifications of sodium bicarbonate (e.g. particle size). Sodium bicarbonate with big particles has a higher dissolution time than that with fine particles (Table 1), which thus has an impact on the rate of reaction; this rate is slower with bigger particles than finer ones.

Table 1. How differently sized particles (i.e. Novabay grades) of sodium bicarbonate affect dissolution time

The amount of CO₂ released by Reaction 2a depends also on the neutralisation value of the acid agent. This in turn depends on the choice of acid/base materials, which indicate the number of parts of sodium bicarbonate neutralised by 100 parts of the leavening acid.

For example, when the neutralisation value of SAPP vs sodium bicarbonate is 72, it means that 100 g of SAPP are enough to release all CO2 that comes from 72 g of Sodium Bicarbonate.

However, it must be noted that a non-desired reaction may take place in case of excess of Sodium Bicarbonate.

This is a saponification reaction between sodium bicarbonate and free fatty acid contained into the formulation (that comes from ingredients like butter or cream). The reaction produces a fatty acid salt that induces an unpleasant metallic taste to the cooked preparation.

SODIUM BICARBonATE USED AS PH BUFFER

Sodium bicarbonate can be used as a pH buffer, which means that it can regulate and maintain the pH of a solution.

With such a characteristic, several existing food formulations already contain and use sodium bicarbonate as a pH buffer. These include instant noodles as well as beverages like energy drinks and ready-to-drink (RTD) coffees or teas.

Using sodium bicarbonate in such a way allows for two benefits. The first of these is better control of the pH of the end-product such that it enables better stability and shelf-life; sodium bicarbonate regulates the pH so as to avoid an acid media which would induce the proliferation of bacteria.

Secondly, sodium bicarbonate creates a feeling of well-being during the digestion. This is as the compound helps to regulate the pH of the stomach after the ingestion of the product and helps with digestion.

SODIUM BICARBonATE USED AS EFFERVESCENT AGENT

The chemical reaction that gives the effervescent power is exactly the same as the one for the baking powder (Reaction 2a). Sodium bicarbonate and an acid agent react together to release CO2.

This property is used for the formulation of sparkling drinks. The two reagents dissolve in the liquid formulation and the reaction begins, releasing CO₂ as gas bubbles in the drinks.

The effervescent power is also used to produce foam for powder drinks like cappuccino or powder energy drinks. The reaction occurs when the powder is mixed with water.

The level of the effervescent power depends on the rate of the reaction 2a. Sodium bicarbonate with fine particles has a fast dissolution time into water and gives a powerful foam with a fast sparking effect. On the contrary, that with big particles has a long dissolution time and gives a weak foam but a long sparkling effect. The choice of the particle size of sodium bicarbonate therefore depends on the desired effect.

With the various advantages of sodium bicarbonate, manufacturers can well benefit by exploring opportunities in innovation with this simple ingredient in their formulations.