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E405ThickenerLow concern
Propylene Glycol Alginate
In plain words
The short version
A modified alginate that stays soluble in acid — thickens dressings and stabilizes the foam head on beer.
Why it's green
It's widely considered safe at the amounts used in food, so we mark it green. The Safety section below has the details.
Safety profile
ADI 0–70 mg/kg body weight (JECFA, 1993). In its 2018 re-evaluation, EFSA set a lower ADI of 55 mg/kg body weight per day and found no safety concern at authorised use levels. The propylene glycol portion is metabolized normally; considered safe within that limit.
The detail
Alginic acid esterified with propylene oxide (propylene glycol) — a chemically modified seaweed alginate.
Emulsifier, thickener, and foam stabilizer that tolerates acid and calcium far better than plain alginate. Stabilizes salad dressings and acidic drinks, and — notably — the foam 'head' on beer.
White powder, soluble in water and in dilute acid, staying stable at low pH where ordinary alginate would precipitate.
Permitted in the EU, the US, and globally with an ADI.
Sources
- EFSA ANS Panel — Re-evaluation of propane-1,2-diol alginate (E 405) as a food additive (2018), EFSA Journal 16(7):5371, doi:10.2903/j.efsa.2018.5371 — European Food Safety Authority, 2018. EFSA ADI 55 mg/kg bw per day; no safety concern
- WHO JECFA database — Propylene glycol alginate (INS 405) — World Health Organization / JECFA, 1993. JECFA ADI 0–70 mg/kg bw
- 21 CFR 172.858 — Propylene glycol alginate (food additive regulation) — U.S. eCFR / FDA. US authorisation as a food additive with use limits
- Commission Regulation (EU) No 1129/2011 — Union list of food additives (Annex II to Regulation (EC) No 1333/2008) — EUR-Lex / European Union, 2011. EU authorisation with maximum levels
Checked against these sources on .
Educational information only. Not medical, dietary or veterinary advice. Spotted an error? Tell us.