Fibroin and sericin, along with very small amounts of waxy substances, mineral salts and coloring matter, are the main constituents of silk1. They both are proteins,accounting for about 75% and 25% of total silk weight respectively. Sericin is primarily amorphous, more water soluble and acts as gum binder to maintain the structural integrity of the cocoon3. Sericin is rich in serine (about 32%), aspartic acid (16.8%) and glycine (8.8%), thus has a high concentration of hydroxyl groups4.