E406: Agar-Agar (Seaweed Hydrocolloid Gel)

Direct Answer

E406 (Agar-Agar) is a natural sulfated galactan polysaccharide hydrocolloid extracted from red algae seaweeds (Rhodophyta). INS 406, ADI is Not Limited (Quantum Satis), forming firm, brittle thermoreversible gels with huge hysteresis (melts at 85°C, sets at 35°C).

Source: Codex Alimentarius / EFSA · Last reviewed Aug 28, 2026

Specs

E-Number Code	E406
INS / Codex Number	INS 406
Functional Class	Gelling Agent, Thickener, Stabilizer (Plant Gelatin Alternative)
Acceptable Daily Intake (ADI)	Not Limited (Quantum Satis)
Chemical Components	Agarose (Gelling polymer) and Agaropektin (Sulfated polymer)
Primary Mechanism	Forms double helices that aggregate into rigid 3D water-trapping gel matrices
Common Target Foods	Vegan jellies, Asian desserts (Yokan), confectionery glazes, microbiological agar plates
Dietary Compliance	100% Vegan (Red marine algae), Halal, Kosher (Animal-gelatin free)
Safety Approval	EFSA Authorized / FDA GRAS (21 CFR 184.1115)

Thermal Hysteresis & Room-Temperature Stability

Agar's massive 50°C hysteresis window (gels at 35°C and will not melt until reheated past 85°C) allows agar jellies and pie fillings to withstand hot summer ambient temperatures without liquefying.