Tuna is popularly eaten raw, an important eating quality, freshness of the tuna, is indicated by the bright red colour of the raw meat. The desirable bright red colour is due to oxygenated muscle pigments is found in akami, the red part of the tuna’s belly.
Myoglobin is the muscle pigment that serves to carry oxygen to the working muscles when the fish is alive. When the fish is cut up, oxygen comes into contact with myoglobin in the exposed tuna meat surface.
In some cases, C02 is used to help maintain the red colour in tuna. There are no direct health implications from eating C02 treated tuna. However, C02 treatment makes tuna appear to be fresh. Tuna which is becoming stale or spoiled will be accompanied by changes in texture, odour, and development of histamine apart from changes in colour. Consumers should not depend solely on the colour but pay more attention to other features to determine the freshness of tuna meat .
A tasteless smoke process is an approved processing technique whereby smoke generated as in a normal food smoking process is first filtered to remove the characteristic smoke flavour before application. This process is allowed to be used in the preservation of tuna. Such products are required to be clearly labelled as smoked so that consumers will know that it has been preserved by smoking, but there are no guarantees.
This tuna below is not C02 treated, it is fresh and red due to the fact that is has been caught in and shipped to Tokyo in the last 24 hours from Northern Japan.
Categories: Sushi Styles