Optimization of Fiber Dyeing with Sour Tea (<i>Hibiscus sabdariffa</i>) to Achieve Red to Brown Shades and Investigate Antimicrobial Properties

Background: In recent years, the use of chemical dyes in the textile industry has caused numerous environmental problems. Consequently, there has been growing interest in natural dyes, particularly those derived from plants, as alternatives. The search for new dye sources, including plant-based options, has become a focal point. Objectives: This study investigated the potential use of the sour tea plant (Hibiscus sabdariffa) as a dye for silk products. Methods: To dye silk goods, it is necessary to clean the silk yarn to remove waste materials such as grease, wax, thorns, shavings, and dirt before the dyeing process. For this purpose, 2 g/L of non-ionic textile soap was used for washing. The silk yarn was soaked and washed in a bath containing 2 g/L of detergent at a liquor ratio (L:R) of 1:50 for 30 minutes at 60°C. Initially, the yarns were introduced into the bath at 30°C, and the temperature was gradually increased to 60°C, where they were washed for 30 minutes. The antimicrobial properties were assessed using the disk diffusion method, measuring the diameter of the inhibition zones against bacteria. Results: The results of the color difference analysis of the samples revealed that the greatest color difference was associated with the dry dye. In this type of dyeing, both in the metachrome and prechrome methods, the oxalic acid variable produced a greater color difference compared to acetic acid. Conversely, in dyeing using the dye extract method, acetic acid resulted in a greater color difference. In the method using the extract of dandelion root, the largest color difference was observed in both the prechrome and metachrome methods. The findings also indicated that the diameter of the inhibition zone for the sour tea extract at a concentration of 50 mg/mL was largest against Staphylococcus aureus (6 mm), while the smallest inhibition zone diameter at the same concentration was observed against Enterococcus faecalis (4 mm). Conclusions: The results of this study demonstrated that the sour tea plant possesses effective color-generating and antimicrobial properties.