Stories of Chitosan 6

Today’s topic is low-molecular chitosan. You may wonder why we skip middle-molecular chitosan, but I will save the topic for the next time.

“Water-soluble chitosan” was once popular. However, as I mentioned previously, chitosan is insoluble in water although it is soluble in acidic solutions such as a hydrochloric acid solution. To make a chitosan powder, chitosan is first dissolved in a hydrochloric acid solution, and then dried. The powder is dissolved in water, but this is by no means “water-soluble chitosan.” To be precise, the powder is called “chitosan hydrochloride.” I reiterate here, but chitosan is not water-soluble.

Needless to say, such chitosan acid salts (hydrochloride, lactate and ascorbate which is “Vitamin C”) are water soluble. However, water-solubility does not mean it is absorbed easily. The molecular weight of chitosan needs to be small enough to be absorbed by the body.

Previously, I mentioned that chitosan is a long chain of D-glucosamine. A short chain of D-glucosamine is called chitosan oligosaccharide (or oligoglucosamine). What is the definition of a short chain? It is a mixture of chains that vary from 2 to 10 units long.

Because of its water-solubility, only chitosan oligosaccharide can be called “water-soluble chitosan.”