Fibroin, a fibrous protein found in silk cocoon was extracted from Thai silkworms (Bombyx mori L. var. Nangnoi Sisaket-1, family Bombycidae). It is essential to dissolve fibroin into solution prior to use. Comparison of the protein pattern by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) from 2 methods of fibroin solubilization between lithium bromide (LiBr) to obtain FP-1 (fibroin powder from method 1) and the tertiary system of CaCl2:EtOH:H2O (1:2:8 molar ratio) to obtain FP-1 (fibroin powder from method 2) showed that the heavy chain subunits of FP-1 was mostly degraded whereas FP-2 giving clearly bands of 37 and 52 kDa. The difference of protein patterns between FP-1 and FP-2 was also shown from SDS-PAGE of the ammonium sulfate precipitation. Under the inverted microscope, the fibroin gel which was formed by the SDS sample buffer was able to bind to the color of aqueous extract from Rosa spp petals. This binding capability of fibroin gel suggests a complexation between fibroin and anthocyanin. Thus, this finding lead to further investigation for a new method of anthocyanin stabilization.
Keywords: Fibroin Silk cocoon Bombyx mori Rosa spp. complexation
