Carrageenan only the lambda form (and the sodium salts of the other two) are soluble. When used in food products, carrageenan has the EU additive E numbers E407 or E407a when present as "processed eucheuma seaweed". Technically carrageenan is considered a dietary fibre. In parts of Scotland and Ireland, where it is known by a variety of local and native names, "Chondrus crispus" is boiled in milk and strained, before sugar and other flavourings such as vanilla, cinnamon, brandy, or whisky are added. The end-product is a kind of jelly similar to panna cotta, tapioca, or blancmange. Although carrageenans were introduced
Tyrian purple this ability has sometimes also been historically exploited by local inhabitants in the areas where these snails occur (Some other predatory gastropods, such as some wentletraps in the family Epitoniidae, seem to also produce a similar substance, although this has not been studied or exploited commercially). The dog whelk" Nucella lapillus", from the North Atlantic, can also be used to produce red-purple and violet dyes. The Phoenicians also made an indigo dye, sometimes referred to as "royal blue" or "hyacinth purple", which was made from a closely related species of marine snail. The Phoenicians established an ancillary production facility on