Boneless Fish

The Boneless Fish (骨なし魚) is a fish-based frozen food invented by Dairei Corporation (大冷株式会社) of Japan in 1998. It is essentially a fish that has been scaled, gutted and deboned by a skilled worker before being reassembled to look like a dressed fish (gutted and with its head and fins removed). The fish is then flash frozen and packaged. It remains uncooked.

It is possible to use this process to manufacture a boneless fish with its head and fins intact. However, this is not very practical.

Purpose
The Boneless Fish was initially intended to feed three groups: the elderly, hospital patients, and schoolchildren. It differs from an ordinary frozen fish fillet, as the Boneless Fish looks just like a dressed fish. It is also cooked in the same manner as an ordinary fish.

Dairei began to market it to families in 2002. Aside from being easy to prepare, cooking boneless fish at home generates very little amount of waste.

Production
The production of the Boneless Fish is labor-intensive. Dairei set up HACCP-certified factories in Thailand, China and Vietnam. The workers cut open the fish and use a pair of tweezers to remove the bones. The end product is then examined to make sure that it is free of bones and then "glued" together using a food-grade enzyme produced by Ajinomoto.

This binding agent is a transglutaminase (product name: Activa TG-B) which is separated from a culture of Streptoverticillium mobaraense. It works by binding the collagen in the fish tissue. At temperatures under 5°C, it may take several hours for the enzyme to do its job properly.

Similar products
The success of Boneless Fish inspired another technology-intensive product, "Fish with Delicious Bones" (骨までおいしい魚; honemade oishii sakana), on sale since 2004. The fish, in the form of a butterfly fillet, is prepared by a patent pending process that uses heat and pressure to tenderize fish bones. It is said the entire fish, including the head and fins, becomes completely edible, much like what happens to canned sardines. It is a joint invention of Maruha Corporation (株式会社マルハ) and Miyajima Soysauce Corporation (宮島醤油株式会社).

Another, chimeral, product is the "Cold Set Bound Fish Kebabs" made from alternating layers of salmon and cod which are "glued" together by transglutaminase.