Lambda-Carrageenan is a non-gelling sulphated galactan extracted from red seaweed (typically Gigartina stellata and Chondrus Crispus).
The structure of all carrageenans consists of a strictly alternating masked repeating unit of (1,3)-linked α-D-galactose and (1,4)-linked β-D-galactose. λ-Carrageenan has the a-linked unit 2,6-disulphated and the β-linked unit is 2-sulphated.