Luthfi 3.0

Cultivation of Porphyra began in the 17th century almost concurrently, in Japan, Korea and China, and has since become one of the most important industries using shallow water areas in all of these countries.

One of the techniques employed in the field uses nori nets hung between poles ( the "pole system"). In this system, the nets are exposed to air and half dried during the period of low tide. Emersion is necessary for the growth of the nori until the young thalli have grown to 2 or 3mm in length. Intertidal pole cultivation is often preferred over raft cultivation in deep water, because it ensures periodic exposure of the proper duration which helps to reduce the incidence of disease and the growth of competitive (weed) species especially epiphytic diatoms. However, this type of cultivation is restricted to the inside of bays with shallow, sandy bottoms. Another method of nori cultivation is also in use, in Japan, where it was devised. The nets are attached to buoys floating on the surface of the sea, so the nori thalli would be soaked in the sea water constantly. With this method it is possible to cultivate the thalli even areas outside of shallow bays in depths of 10-20m. This method is referred to as the "floating system" of cultivation.

The growth of nori thalli is mostly inhibited by high temperature. Temperatures are higher in the dark, than in the light. These conditions (high temperatures at night) occurs in mid to late summer, and causes heavy damage. To overcome this problem, nets with young thalli can be preserved in a deep-freeze. When the young thalli of nori reach a length of 1 to 3cm, they are withdrawn from the culture field together with the nets and are dried in the air until the water content of the thalli decreases by 20 to 40%, which usually requires 2 to 3 hours. They are the put into vinyl bags and stored in a freezer at 20 degrees celcius. Cultivation in the nori season does not have to be interrupted, as the nets can be brought back to the nori fields whenever they are required.

USES OF PORPHYRA:

Porphyra has high contents of digestible protein (2025% wet weight) and free amino acids (especially glutamic acid, glycine, and alanine), which are responsible for it’s specific taste. Porphyra has a vitamin C content very similar to lemons, is rich in vitamin B, and proves an excellent source of iodine and other trace elements. Nori is also a source of vitamin E used in facial creams, and contains antioxidants which are substances that slow food spoilage and eliminate free radicals from the body.

In Japanese railway station buffets, hotels and restaurants, nori takes the place of the sandwich, which is presented to the public under the name of "sushi". This is prepared by placing boiled rice and strips of meat or fish on a sheet, which is then rolled up and cut into slices. Nori is also cut up into small fragments and used in biscuit manufacture.