Brown algae (class Phaeophyceae) are a large and diverse group of marine seaweeds that include some of the most familiar and commercially important species — kelp, wakame, kombu, and bladderwrack among them. They get their characteristic brown-green colour from the pigment fucoxanthin.
While many brown algae species are eaten directly as food (particularly in East Asian cuisines), their cell walls are also the primary industrial source of alginates — polysaccharides extracted and used as thickening, gelling, and stabilising agents across the food industry. Alginates appear in products ranging from ice cream and salad dressings to processed meats and bakery fillings.
Brown algae are ecologically vital, forming vast underwater forests that support marine biodiversity. Kelp forests off southern Australia are among the most productive ecosystems on the planet.
How it's produced
Brown algae for alginate extraction are sourced both from wild harvest and from aquaculture. Wild harvesting involves mechanically cutting or collecting seaweed from coastal waters, often from kelp beds. Farmed brown algae — particularly species like Saccharina and Undaria — are cultivated on ropes or nets suspended in coastal waters.
To extract alginates, the harvested seaweed is washed, treated with alkali to dissolve the alginate from the cell walls, filtered, and then precipitated into a usable powder or gel. Major alginate-producing regions include China, Norway, Chile, and parts of Southeast Asia. Australia has significant wild kelp resources but limited commercial alginate production.
What it costs the planet (per kilo)
≈ Estimated from its category — typical for vegetables, not measured for this item yet. Sources & methods →
What comes from this
Your household's take
One thumb per person, shared with your household — it steers what the wider-web shelf and the swap chips offer you. Tap again to take it back.
✎ Spotted something wrong? Suggest a correction
Checking who you are...