Seaweed, a versatile healthy ingredient

Created on 2024.10.15

Seaweed is rich in minerals, dietary fiber, and vitamins, and can prevent lifestyle-related diseases, making it an essential healthy food ingredient.

The Japanese archipelago is long and narrow, with a coastline of 34,000 kilometers, ranking sixth in the world, and is home to numerous seaweed production areas, where about 1,500 species of seaweed grow. Some seaweed fossils have also been found in Jomon period ruins. In ancient times, seaweed was used to pay taxes, was an important offering for rituals and a medicine, and appeared in poems such as the "Manyoshu." In Japanese, the pronunciation of kelp is similar to "happy." Therefore, kelp is still a food with auspicious meaning today, made into kelp rolls in the traditional New Year's dish "Osechi Ryori," or used as one of the betrothal gifts.

Seaweed is rich in minerals such as calcium, iodine, magnesium, and iron, as well as dietary fiber. It can lower cholesterol levels in the body, control blood sugar spikes, and promote intestinal peristalsis and metabolism. In addition, seaweed can be used as a thickener for jelly or ice cream, and its utilization in fields outside the food industry, such as medicine and cosmetics, is also attracting attention.

Several common seaweeds

Kelp

It is said that Japanese people have been eating kelp since the Jomon period. Kelp is an essential ingredient for making Japanese dashi broth and is the "cornerstone" of Japanese cuisine.

Dried kelp

It is difficult for us to imagine what dried kelp originally looked like. The length of kelp fronds varies by variety, with some reaching about 8 meters. Kelp is divided into natural kelp and farmed kelp, with over 90% of natural kelp coming from Hokkaido. Among them, kombu, Rausu kombu, and Rishiri kombu are mainly used for making Japanese dashi, while Hidaka kombu is primarily used for stews. Tsukudani (a Japanese dish made by simmering small fish and seaweed with soy sauce and sugar) kelp is also a popular filling for rice balls. Long-term storage and aging can enhance the freshness of dried kelp.

Dried Kelp (PIXTA)

The umami flavor of kelp comes from glutamic acid. In 1907, Professor Kikunae Ikeda of the Imperial University of Tokyo discovered glutamic acid in kelp, which became a raw material for chemical seasonings. Kelp is rich in minerals, vitamin B, and dietary fiber. Among them, soluble dietary fiber contains components that enhance anti-cancer immunity.

Kombu Roll (PIXTA)

Wakame

When wakame is placed in hot soup, it turns from brown to emerald green in seconds. Wakame grows to about 1 meter long and matures in spring and summer. Ninety percent of domestically produced wakame is artificially cultivated.

Wakame in the sea (PIXTA)

Depending on the intended use, wakame can be divided into cut wakame, dried wakame, and chewy salted wakame. Wakame has a wide range of culinary applications and can be used to make miso soup, Western-style soups, vinegared cold dishes, salads, or as a garnish for udon, soba, ramen, stir-fries, stews, and tempura, among other dishes.

Boiled Wakame (PIXTA)

Cucumber and Wakame Salad (PIXTA)

The growth point of wakame is located in the folded part at the bottom, which is called the "holdfast." Only in spring, when fresh wakame is sold in stores, will it produce mucus when cut. Making it into a salad or adding it to soup gives it a smooth texture, making it suitable for consumption during the hot summer months when appetite is poor. The water-soluble dietary fiber content in wakame holdfasts is higher than in the leaves, which can lower cholesterol levels in the body.

Wakame holdfasts after boiling (left), chopped wakame holdfasts mixed with yuzu vinegar, garlic, and ginger (PIXTA)

Hijiki

Sea lettuce products are mainly divided into sea lettuce sprouts and sea lettuce stems, with the former characterized by soft leaves and the latter having a chewy stem. Both can be further divided into fresh sea lettuce and dried sea lettuce. Ninety percent of the sea lettuce sold in Japan is imported. In Japan, people generally soak dried sea lettuce before stir-frying it with ingredients like carrots, fried tofu, soybeans, and shiitake mushrooms, then adding Japanese dashi, soy sauce, and sugar for simmering.

Spring sea lettuce on the shallow beach (nippon.com)

Umibudo is versatile and can be used to make dishes such as Japanese rice dishes, salads, omelets, tempura, vegetable and tofu salads, vinegared cold dishes, and miso soup. In addition, umibudo is rich in calcium and is also suitable for calcium supplementation.

Boiled Umibudo (PIXTA)

Mozuku

Ninety percent of Japan's mozuku is Okinawan mozuku, which is artificially cultivated in Okinawa. This type of mozuku has less mucus and a chewy texture. In the Hokuriku region, there is a long and highly viscous type of mozuku called "ito-mozuku." The fucoidan contained in mozuku is a water-soluble dietary fiber that is more easily absorbed when added to broth or miso soup. In addition, when consumed with vinegar or soy sauce, the citric acid in vinegar promotes calcium absorption. Vinegared mozuku is highly nutritious and has a smooth, refreshing texture, making it an excellent seasoned side dish.

Vinegared Mozuku (PIXTA)

Nori

The main types of nori sold in Japan are Porphyra yezoensis and Porphyra tenera. "Fresh nori" is harvested directly from the sea, dried to become "dried nori," and then roasted to become "roasted nori." Nori products sold in stores are all roasted nori.

Nori cultivation in the Ariake Sea

The production process for dried nori or roasted nori is similar to papermaking, where shredded nori paste is filtered, flattened, thinned, and dried to make sushi, onigiri, isobeyaki (a grilled mochi wrapped in nori - translator's note), furikake, or used to garnish zaru soba and ramen. Flavor nori is made by cutting roasted nori coated with dipping sauce into small pieces and is an excellent accompaniment to meals. 30% of nori is for household consumption, 10% is for gifts, and 60% is for processing. Among processed nori, much is used to make convenience store onigiri. Fresh nori can be used to make tsukudani, miso soup, or pasta. Nori is rich in vitamin C, protein, and dietary fiber, making it a well-deserved "sea vegetable."

Nori (PIXTA)

Hand-rolled Sushi (PIXTA)

Ulva and Aonori

Ulva and aonori are extremely similar in appearance and both belong to the genus Ulva, but aonori has a stronger aroma. Ulva and aonori are used to make okonomiyaki, yakisoba, tempura, furikake, miso soup, takoyaki, and pasta, among other dishes.

Ulva Miso Soup (left), Aonori sprinkled on Takoyaki

Agar-agar

Agar-agar is a red algae and a raw material for making agar and jelly. When agar-agar is soaked in water and dried, repeating this process four or five times will cause the red color to fade to colorless. Then, soak it in water overnight, boil it over high heat, and strain it to produce agar-agar. Agar-agar has always been an essential ingredient in making sweets, and recently it has also been used in the production of cosmetics or as a thickener for diet meals, with its uses becoming increasingly widespread.

Agar-agar (PIXTA)

Agar-agar after several days of sun-drying (PIXTA)

Cock's Comb

Cock's comb is a type of red algae that can be used for plating sashimi or making seaweed salad, named for its resemblance to a rooster's comb.

Seaweed salad made with cock's comb (Sea Vegetable)