Bombyx mori Jul 1/1. Briefly, cocoons of Nangnoi Srisaket 1 (yellow-shell) and Jul 1/1 (white-shell) were degummed in 0.02 M Na2CO3. Dried silk fibroin was dissolved in 9.3 M LiBr solution at 60oC for 4 h. Silk fibroin solution was then dialyzed against deionized water for 2 days to remove LiBr and centrifuged at 10,000 rpm, 4oC for 20 min to remove impurities. The final concentration of silk fibroin solution was around 6.5% (w/v) [6]. Commercial sericin powder (heat extraction, Suranaree University of Technology) was dissolved in deionized water at 60oC for 30 min and blended with silk fibroin solution at 0, 1, 2 and 5% sericin.