Silk cocoon is composed of sericin and fibroin. Sericin is the glue-like substance that helps silk floss form the shape of a cocoon. It is 25% of cocoon’s weight. This substance protects the silk worm inside with hypoallergenic properties. Even though most of this glue like substance gets washed away during the production of silk bedding, there’s enough that remains to carry on hypoallergenic functionalities and repels bacteria, fungus, dust mite and bed bugs. For someone who is allergic to down, silk is the best natural alternative.
Fibroin consists of the other 75% of cocoon’s weight. Fibroin is the protein structure that we commonly called silk floss.