Stories of Chitosan 8

Did previous sessions make it easier for you to understand what chitosan might be? In this session, I would like to change gears to talk about crab shell, which is used to produce chitosan.

Living organisms have some defense mechanisms to protect their bodies. For instance, humans have advanced and complex “immunity.”

Then, what about shellfish such as crab? They don’t have an advanced immune system like humans. Instead, they are covered by a hard shell containing chitin.

Of course, the human immune system is not perfect. Therefore, we need to ingest small amounts of naturally-occurring substances that protect other organisms to complement the weaknesses of our own immune system. It is important to consume the substances in their natural state as much as possible.

With the crab shell powder used in “Dream,” we were very particular about how to keep it close to in its natural state. Powder products are generally difficult to sterilize. The only available options are heat treatment or chemical treatment. However, heat treatment denatures proteins or even carbonizes them at extreme heat. Chemical treatment produces residual chemicals.

Because crab is demersal, bacteria attached to crab shells differ from those on land. Such bacteria are troublesome. They are resilient, making it difficult to sterilize at first. Extreme heat could kill them easily. However, proteins, which account for 30% of crab shells, could be denatured if we apply too much heat. Chitin, which accounts for another 30%, could also be degraded.

After much trial and error, we established an elaborate high-pressure pasteurization method, where crab shell powders in pouches are put in a large pan to apply pressure. The powders are concurrently steam-heated for sterilization. We worked so hard to establish this method.