Deodorizing function and antibacterial activity of fabrics dyed with gallnut (Galla Chinensis) extract

To examine the deodorizing function and antibacterial activity of fabrics dyed with gallnut extract, a natural dying aqueous solution was prepared by extraction from gallnut using water at 90℃ for 90 min with a fixed liquor ratio of 1:10. The colorimetric properties, the deodorization performance and the antibacterial ability of fabrics (cotton, silk and wool fabrics) dyed with the natural colorant extract solution were evaluated. The main component of the colorant (yellowish color) in the gallnut extract was found to be gallotannin. The K/ S value of the dyed fabrics increased in the order of cotton < silk <wool. From curve fitting of ultraviolet-visible spectra, the gallnut extract obtained in this study was found to comprise gallotannin (69.0%), gallic acid (25.7%) and methyl gallate (5.3%). The dyed fabrics showed a better deodorizing function against ammonia, trimethyl amine and acetaldehyde, compared to the control (undyed) fabrics. The dyed fabrics showed an excellent antibacterial function (99.9% reduction) against Staphylococcus aureus and Klebsiella pneumonia. These results highlight the strong potential of the natural dyed fabrics as a functional material with both high antibacterial activity and deodorizing function.