E333i - Monocalcium citrate

Monocalcium citrate is the least-used of the three calcium citrates specified under E 333. Where the sodium citrates are chosen for buffering, the calcium citrates are usually chosen for the calcium itself: the ion firms plant tissue by cross-linking pectin in cell walls.

That firming effect is why calcium citrates appear in canned and bottled fruit and vegetables. Without added calcium, tomatoes and cherries collapse into mush during heat processing; with it, they hold their shape. Monocalcium citrate is the most soluble and most acidic of the three, so it is the form used where the calcium needs to dissolve quickly without pushing pH up.

Canned and bottled fruit and vegetables, jams and jellies, some soft drinks and fruit preparations, calcium-fortified plant drinks, and dietary supplements.

Calcium citrates are authorised in Great Britain as E 333 and sit in Group I, permitted at quantum satis. Monocalcium citrate is specified as E 333(i).

EFSA's re-evaluation of citric acid and its salts found no safety concern at reported uses and concluded that no numerical ADI is needed.

• FSA Register of Food Additive Authorisations — E 333
• FSA/DHSC: Approved additives and E numbers
• Assimilated Regulation (EU) No 231/2012 (specifications, E 333(i))