Sodium tartrates
The sodium salt of tartaric acid, a natural fruit acid. Used to control acidity and stabilise texture in processed foods.
What is it?
Sodium tartrates are the sodium salts of tartaric acid, a naturally occurring organic acid found in grapes, tamarinds and other fruits. They exist in two forms: monosodium tartrate (E335i) and disodium tartrate (E335ii). In food use, they are white crystalline powders that dissolve readily in water.
What does it do?
As an acidity regulator, sodium tartrates buffer the pH of a product, keeping it stable during manufacture, storage and heating. They also act as sequestrants, binding trace metal ions that would otherwise catalyse oxidation or discolouration. In some applications they improve the texture and set of gels and emulsions.
Where you will see it
Found in confectionery, jams and preserves, baked goods, soft drinks, and some dairy desserts. They are also used in wine stabilisation and certain dietary supplement tablets. On a UK ingredient label the additive appears as 'sodium tartrates', 'E335', 'monosodium tartrate' or 'disodium tartrate'.
What the science says
Tartaric acid and kidney stones
Tartrate is handled by the kidneys, and at very high supplemental doses there is theoretical concern about oxalate or tartrate crystallisation in people already prone to kidney stones. Food-level intake is far below the doses studied. No clinical evidence links normal dietary exposure to kidney stone risk.
Tartaric acid is metabolised in the body; the kidney excretes tartrate, and at pharmacological doses animal studies have noted renal tubular effects, but these are not observed at dietary exposure levels.
Sodium content
Disodium tartrate contributes sodium to the diet. In processed foods where multiple sodium-containing additives are used alongside sodium from salt, cumulative sodium intake is a relevant consideration for people managing blood pressure or cardiovascular risk.
NHS and SACN guidance caps sodium intake at 2.4g per day (equivalent to 6g salt). Sodium from additives such as sodium tartrates counts toward this total, though the amounts contributed at typical use levels are small.
EFSA re-evaluation outcome
EFSA completed a full re-evaluation of tartrate-based additives in 2014 and concluded there was no reason for safety concern at current use levels. No numerical acceptable daily intake was considered necessary because the substance is an ordinary constituent of fruit and is metabolised by normal pathways.
EFSA established that there was no safety concern for the use of sodium tartrates as food additives at the reported use levels and set no numerical ADI, concluding the group ADI 'not specified' was appropriate.
Where it stands with the regulators
Who should be careful
People on a medically supervised low-sodium diet should note that disodium tartrate (E335ii) contributes sodium. Those with a history of kidney stones may wish to discuss high intake of tartrate-containing foods with their GP. Look for 'E335', 'sodium tartrates', 'monosodium tartrate' or 'disodium tartrate' on the label.
The honest read
Sodium tartrates are among the most straightforwardly characterised acidity regulators in use. They derive from tartaric acid, a compound that has been present in food (especially wine and grapes) throughout human history. The 2014 EFSA re-evaluation, which covered the full group of tartrate additives, found no evidence of concern at dietary exposure levels and saw no need to set a numerical daily intake limit. The only practical considerations are the sodium contribution from the disodium form and theoretical questions about very high tartrate intake in people with existing kidney conditions, neither of which is supported by clinical evidence at food-level exposures.
Related additives
Common questions
Is E335 banned in the UK?
No. Sodium tartrates are approved food additives in the UK under the FSA approved-additives list and assimilated EU Regulation 1333/2008.
Does E335 contain allergens?
Sodium tartrates are not derived from any of the 14 declarable allergens under UK food law and carry no allergen declarations. They are derived from tartaric acid, which originates primarily from grapes, but the purified additive does not carry grape protein.
What foods contain E335?
Confectionery, jams and preserves, baked goods, soft drinks, dairy desserts and some dietary supplements. Check ingredient lists for 'E335', 'sodium tartrates', 'monosodium tartrate' or 'disodium tartrate'.
Is E335 vegan?
Yes. Sodium tartrates are produced synthetically from tartaric acid (commonly derived from winemaking by-products) and contain no animal-derived ingredients.
Sources
- EFSA ANS Panel: Re-evaluation of tartaric acid (E334), sodium tartrates (E335), potassium tartrates (E336), potassium sodium tartrate (E337) and calcium tartrate (E354) as food additives
- UK FSA Approved Additives and E Numbers
- SACN Salt and Health report
- EU Regulation 1333/2008 on food additives (Annex II)
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