Introduction to Citric Acid


Citric Acid is the most important organic acid. It can be used as an acidifier, as a chelating agent, or as a cleaning agent. So many uses of citric acid, then we should call it a multipurpose citric acid.

What comes to your mind when you hear Citric Acid? Lemons, lime, and oranges are some common fruits.  The sour taste of citrus fruit leads people to think that citrus fruit is a source of citric acid. However, the content of citric acid in lemon is just 6%. So what are other sources from which we get this multipurpose citric acid? Citrus fruits are not the only source of citric acid, whereas we can prepare citric acid from molasses. Molasses is the sweet, dark syrupy byproduct made during the extraction of sugar from sugarcane and sugar beets. It's availability and relatively low price make it a desirable raw material for citric acid anhydrous production.

We should be thankful to the great American food chemist James Currie who discovered the industrial process to manufacture multipurpose citric acid. For Citric Acid production, Aspergillus nigeris the fungi used in the fermentation process. A possible raw material for use in fermentation could be molasses garnered from sugarcane.


Submerged Fermentation:


Submerged Fermentation is commonly used for citric acid production. About 80% of citric acid production in the world is obtained by submerged fermentation. Stirred fermenters and tower fermenters are used in submerged fermentation. Sugar and starch-based media are used in submerged fermentation for citric acid production.


Surface Fermentation:


Surface fermentation is the process of citric acid production in which liquid/solid surface culture is used. This process occurs in the fermentation chamber. To control the temperature and supply of air to the microorganism, a high amount of heat and high aeration rates are provided. When the fermentation is completed, the tray is washed to remove the impregnated citric acid.


Solid-state Fermentation:


Solid-state fermentation uses agro-industrial residues like fruit waste, and rice bran for citric acid production. Aspergillus niger is the most commonly used microorganism in this fermentation. The solid substrate is moistened to raise the effectiveness of citric acid production.


Application of Citric Acid


In the food and beverage industry, citric acid is used in pH adjustment to provide uniform acidity. It acts as an acidulant for jellies and jams.

In the Dairy industry, it acts as an emulsifier in ice creams and processed cheese.

In Pharmaceutical Industry, it acts as effervescent in powders and tablets in combination with bicarbonates.

It helps in metal cleaning by removing metal oxides from the surface of ferrous and non-ferrous metals. Also, it is used as a co-builder with zeolites, mainly in concentrated liquid detergents.


Citric Acid Global Market


According to market trends, citric acid is majorly used in the food and beverage industry. The following pie chart shows the world consumption of citric acid.

Asia is the largest consumer of citric acid and citrates accounting 28% of world consumption in 2015, whereas China is the largest player in citric acid production accounting 59% of world production in 2015.