Green sea urchins are found from the southern areas of Hokkaido down to Kyushu. Since they have a low yield, most are consumed locally. Besides Japan, many are imported from South Korea, China, the US, Canada, Chile and other places. The most commonly eaten green sea urchins are Short-spined sea urchins, which are valued as the highest quality of sea urchin. Every sack of sea urchin tastes sweet and melts in your mouth. This sushi topping has a rich ocean flavor and goes well with dry wine or champagne.
Trivia 1：The thing we eat as " Sea urchin" is actually Sea urchin's gonad. And how to recognize the gender of sea urchins is to see the color of its gonad. Male gonad is deep yellow and female gonad is orange nearly red. The male gonad tastes more sweeter and rich.
Trivia 2 : The umami flavor of sea urchin is mainly made up of amino acids and nucleic acids. Some of the amino acids found in this topping are glycine, alanine, valine and glutamine. The sweetness of sea urchin is related to the glycine and alanine content, while its richness comes from glutamine. It doesn’t have a high inosinic acid content, which is a nucleic acid, but the synergistic effects of the inosinic acid and glutamic acid bring out the umami flavor. It also contains methionine, an amino acid, which contributes greatly to the unique flavor that sea urchin is known for.
Trivia 3 : The sea urchin soaked in salt water will get sweetened and tastier when they take them out from the salt water and let them rest for a day. But if they don't know how to handle them and just serve them as they are just only taken from the salt water, the sea urchin will taste bland and watery.
Trivia 4 : At Mutsu city, in Aomori prefecture, they are working on the testing project of farming sea urchins, feeding them various cabbages (standard Cannonball Cabbage and Chinese napa cabbage and etc). Those vegetables are recycled food wastes from super markets. The idea is that during the winter season, the natural sea urchin becomes rare and there is barely one on the market, therefore they get those farmed sea urchins on the market instead and aim to generate a new source of income. The farmed sea urchin gets as ripe as the natural one, and those ingredients that create the acquired sea urchin flavor such as Glycine, Methionin and Amino acids are well contained.
Fukui Ishikawa Yamaguchi Fukuoka