An edible alternative to plastic water bottles made from seaweed has topped the British round of a European Union competition for more sustainable products.

The spherical form of packaging, called Ooho and described by its makers as "water you can eat", is biodegradeable, hygienic and costs one British penny (two Singapore cents) per unit to make. It is made chiefly from calcium chloride and a seaweed derivative called sodium alginate, reported The Guardian.

Ooho designer Pierre Paslier described the product as being like a "man-made fruit", which uses a double membrane to contain water. To carry larger quantities of water, a number of the capsules can be packed into a larger and thicker skin, much like an orange.

He said: "So many things are wrong about plastic bottles: The time they take to decompose, the amount of energy that goes into making them and the fact that we are using more and more."

Other finalists presented a water purifier that captures energy from solar panels, an index that allows investors to track their financial exposure to carbon and a process that uses bio tanks to create paper from waste straw instead of trees.

Entries were showcased yesterday at the Science Museum in London.