E333I - Monocalcium citrate

At a glance

• Also called: E333i; a member of the calcium citrates group
• What it does: helps regulate acidity, binds metals (sequestrant), and stabilizes products
• Typical uses: drinks, fruit preparations, desserts, sauces, and some dairy-style foods
• How it’s made: neutralizing citric acid with a calcium source, then purifying
• Dietary notes: calcium salt; suitable for vegetarians and vegans
• Label check: look for “monocalcium citrate,” “E333i,” or “calcium citrates (E333)”

Why is Monocalcium citrate added to food?

Food makers use monocalcium citrate to keep acidity where it should be and to bind trace metals that can cause off-flavors, discoloration, or loss of nutrients. These roles are known as acidity regulation, sequestration (metal binding), and stabilization in additive law.¹ In practice, it helps formulas stay consistent over shelf life and can improve heat and storage stability in beverages, fruit fillings, and other aqueous foods.²

What foods contain Monocalcium citrate?

You’re most likely to find E333i in products where pH control or metal binding matters, such as beverages, fruit spreads and fillings, confectionery, and dairy-style drinks or desserts. In the European Union, E333 (calcium citrates, including monocalcium citrate) is authorized across a wide range of categories listed in Annex II of the food additives regulation; always check the ingredient list to confirm its presence.²

What can replace Monocalcium citrate?

Possible alternatives depend on why it’s used:

• For acidity regulation or buffering: citric acid, sodium citrates, or potassium citrates
• For sequestration or stabilization: sodium phosphates, calcium phosphates, or diphosphates

How is Monocalcium citrate made?

Manufacturers typically produce calcium citrates by neutralizing purified citric acid with a calcium base such as calcium hydroxide or calcium carbonates. The mixture is filtered, crystallized, and dried to obtain the desired calcium citrate salt (monocalcium, dicalcium, or tricalcium), meeting purity and identity specifications set in EU law.¹

Is Monocalcium citrate safe to eat?

Calcium citrates (E330–E333) have been re-evaluated by the European Food Safety Authority (EFSA), which concluded they do not raise a safety concern at reported uses and exposures; the group acceptable daily intake (ADI) was “not specified,” a category reserved for additives of very low toxicity at typical use levels.³ In the United States, calcium citrate appears on the FDA’s Food Additive Status List as Generally Recognized as Safe (GRAS) when used in accordance with good manufacturing practice.⁴

ADI means Acceptable Daily Intake, the amount considered safe to consume every day over a lifetime. An “ADI not specified” indicates no numerical limit was needed based on available data and typical uses.³

Does Monocalcium citrate have any benefits?

• In food: It buffers pH and binds metal ions, which helps maintain flavor, color, and vitamin stability in water-based products.¹
• As a nutrient source: Because it’s a calcium salt, it can contribute to calcium intake when used for fortification. Calcium is an essential mineral needed for bones, muscles, nerves, and blood clotting.⁵ Calcium citrate is also a common supplement form because it can be taken with or without food.⁵

Who should avoid Monocalcium citrate?

Most people don’t need to avoid E333i in normal amounts found in food. However:

• People who must limit calcium (for example, due to hypercalcemia or certain kidney conditions) should consult a healthcare professional, especially if also taking calcium supplements.⁵
• Very high calcium intakes from all sources can cause side effects such as constipation and may increase the risk of kidney stones in some people; adhere to established upper intake levels.⁵

If you have a specific medical condition or are on a restricted diet, ask your clinician or dietitian for personalized advice.

Myths & facts

• Myth: “E-numbers are always artificial.” Fact: E-numbers are just codes for additives assessed for safety in the EU; many are identical to naturally occurring substances like citric acid and its salts.
• Myth: “Monocalcium citrate is the same as citric acid.” Fact: It’s the calcium salt of citric acid, used mainly for buffering and metal binding rather than sourness.
• Myth: “It adds a strong taste.” Fact: At typical levels, it adjusts acidity and stabilizes flavor rather than adding a distinct taste.

Monocalcium citrate in branded foods

On labels, look for “monocalcium citrate,” “E333i,” or “calcium citrates (E333).” Many manufacturers group the salts under “E333,” so the exact form (mono-, di-, or tri-) may not always be specified. If you want to track it in your diet, read the ingredient list and, when available, the additive index on the brand’s website.

References

Footnotes

1. Commission Regulation (EU) No 231/2012 — Specifications for food additives (including E 333 calcium citrates). https://eur-lex.europa.eu/eli/reg/2012/231/oj ↩ ↩² ↩³

2. Regulation (EC) No 1333/2008 — Food additives, Annex II (Union list of authorized food additives). https://eur-lex.europa.eu/eli/reg/2008/1333/oj ↩ ↩²

3. Re-evaluation of citric acid (E 330), sodium citrates (E 331), potassium citrates (E 332) and calcium citrates (E 333) as food additives — EFSA Journal. https://www.efsa.europa.eu ↩ ↩²

4. Food Additive Status List — U.S. FDA. https://www.fda.gov/food/food-additives-petitions/food-additive-status-list ↩

5. Calcium Fact Sheet — NIH Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/Calcium-Consumer/ ↩ ↩² ↩³ ↩⁴