Agri Kultuur September / September 2016 - Page 65

The lower intertidal and shallow subtidal zones are rich in diversity of seaweeds. In the oceans, along with microscopic algae known as phytoplankton, seaweeds form the base of the food chain.      Considered excellent detoxifying agents. Produce alginate, a substance of considerable economic value and used as a gelling and emulsifying agent. For example, alginate prevents the formation of ice crystals in ice cream. In the medical industry, alginate is used to encapsulate tablets in powder form and to form fracture castings and moulds. Other products containing alginate include brownie mix, frozen foods, desserts, relishes, salad dressings, sauces, gravies and even beer foam. Kelp also contains an astonishing amount of vitamins and minerals, particularly iodine, which has a normalizing effect on the thyroid gland that controls the body’s growth and development. In many countries, kelp is harvested as a feed and nutritional supplement for commercially farmed animals. Due to its high micronutrient contents, kelp is widely used as fertilisers and as plant growth stimulants. Fleshy Red seaweeds  While the seaweed industry in the West is based mainly on seaweed extracts, in the east seaweeds are cultivated in huge quantities for human consumption. Red seaweeds from the genus Porphyra (purple laver) in particular, contributes at least 80% of all seaweed harvested all over the world.  In Asia, Porphyra (known as nori) is eaten as a whole seaweed either dried or in soups, and globally as tasty wrappings for sushi. The iodine and high vitamin and protein content of nori makes it attractive, as does the relative simplicity of its mariculture (sea farming), which began more than 300 years ago in Japan. Red seaweed extracts Beside food for direct consumption, red seaweeds are also important for their phycocolloid extracts. Phycocolloids are seaweed derivatives that cause particles to remain suspended in solution and are, therefore, excellent as stabilizing and gelling agents. The main phycocolloids derived from red seaweeds are carrageenan and agar.  Carrageenan is highly sort after in western societies where it is especially important in the dairy industry. Milkshakes, cheese, yoghurt, powdered milk (including baby formula) all possess red seaweed carrageenan extracts. Carrageenan is also used in toothpaste, cosmetics, shampoos, paints and pet food.  Agar on the other hand, has its most important use as a medium on which to culture fungi and bacteria in microbial and medical pathological research. In food for 