Sodium Citrates (sodium citrate)

Sodium citrates are sodium salts derived from citric acid that appear as white crystalline powders with a slightly salty, sour taste. Their high solubility in water makes them extremely versatile. These compounds exist in three main forms: sodium monohydrate, sodium dihydrate and sodium trihydrate, with sodium trihydrate being the most common. Due to their wide range of uses, sodium citrates play a key role in the food and pharmaceutical industries as acidity regulators, emulsifiers and preservatives.

Origin

Sodium citrates have both natural and synthetic origins. Naturally occurring citric acid is abundant in citrus fruits such as lemons and limes. Industrial production usually involves the fermentation of carbohydrates such as corn or sugar beets by the fungus Aspergillus niger, which produces citric acid. This citric acid is then neutralised with sodium hydroxide or sodium carbonate to produce sodium citrate. This method ensures a consistent and scalable supply for a variety of industrial needs.

Characteristics and applications in the food industry

The use of sodium citrate in food processing can be attributed to its unique properties:

• Acidity control: they help maintain or adjust pH levels in foods and beverages.
• Buffering capacity: sodium citrates stabilize pH levels, preventing drastic changes that can affect product stability.
• Emulsification.
• Chelation: By binding to metal ions, they increase product stability and shelf life.
• Preservation: They inhibit the growth of microorganisms, thereby extending the shelf life of various foods.
• Flavour enhancement: Their slightly acidic taste can improve the overall flavour profile of foods and beverages.

Use in ultra‑processed foods

Sodium citrates are widely used in ultra‑processed foods due to their multifunctional benefits. Here is a detailed look at their uses:

• Processed cheese: sodium citrates prevent fat separation and improve texture, making cheese smooth and creamy. They also improve melting properties, which is essential for products like cheese slices and spreads.
• Beverages: in sodas, sports drinks and fruit juices, sodium citrates balance acidity, ensuring a consistent and pleasant taste. They also help preserve the beverage by inhibiting the growth of microorganisms.
• Jellies and jams: sodium citrates prevent the crystallization of sugars, provide a smooth and spreadable texture and extend shelf life by maintaining stability.
• Canned foods: By chelating metal ions, they reduce oxidation of fats and oils, preventing spoilage and rancidity. This is essential for the long shelf life required for canned foods.
• Bakery products: As buffering agents, sodium citrates maintain the desired pH level in doughs and batters, preventing the growth of micro‑organisms and extending shelf life. They also contribute to the proper leavening and texture of baked goods.

Effect on human health

Although sodium citrates are generally considered safe (GRAS) when consumed at typical levels found in foods, there are several health aspects to keep in mind:

• Sodium intake: High sodium citrate consumption can contribute to elevated sodium levels, a known risk factor for hypertension and cardiovascular disease. Given the prevalence of high‑sodium diets in many parts of the world, this is a significant problem.
• Allergic reactions: although rare, some individuals may experience allergic reactions to citrate. Symptoms may include skin rashes, itching, or gastrointestinal discomfort.
• Kidney health: People with compromised kidney function should monitor their intake of sodium citrate because it can affect the body's acid‑base balance, which can lead to complications.
• Digestive problems: In some cases, high sodium citrate intake can cause gastrointestinal problems, including nausea, bloating or diarrhea.

Although sodium citrates are highly functional and beneficial in many food applications, their consumption should be kept within reason to avoid potential health risks.

Sources

1. U.S. Food and Drug Administration (FDA). "CFR - Code of Federal Regulations Title 21." FDA. Available at: www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=184,1751.
2. National Center for Biotechnology Information (NCBI). "Sodium Citrate." PubChem. Available at: pubchem.ncbi.nlm.nih.gov/compound/Sodium‑citrate.
3. World Health Organization (WHO). "Evaluation of Certain Food Additives." WHO Technical Report Series, no. 940. Available at: www.who.int/publications/i/item/9789241209406.
4. Codex Alimentarius. "General Standard for Food Additives." Codex Alimentarius. Available at: www.fao.org/fao‑who‑codexalimentarius/codex‑texts/dbs/gsfa/en/.

These sources provide a solid scientific basis that ensures that the information presented is accurate and reliable.