Flavonol-quercetin functionalized silk dyeing under different liquid fermentation conditions

Onion peels have been fermented prior to dyeing of silk to enhance the dyeing efficiency. The conditions have beenchanged by mixing the nutrients and microorganisms, and the differences in color and fastness are evaluated. Sucrose anddry yeast (Saccharomyces cerevisiae), important factors affecting the fermentation, have been used as nutrients andmicroorganisms for fermentation. The study has also been done without any additive and by adding only sucrose or yeast forcomparison. The fermentation conditions are maintained at 35 °C for 8 h. The L*, a*, b*, and K/S values of silk has beenmeasured using a colorimeter. The value of L* is found highest when microorganisms are added, while a*, b* and K/S valuesare found lower after fermentation under all conditions. The value of a* is found the lowest when both yeast and sucrose areadded simultaneously; b* is the lowest when microorganisms are added. Fastness to light, washing, and perspiration arefound higher after fermentation. The dyeing of silk using fermented solutions made of onion peels shows a distinctive colorchange and good color fastness. This may be helpful in developing natural dyeing products of various colors