Mixture approach for optimizing the recovery of colored phenolics from red pepper (Capsicum annum L.) by-products as potential source of natural dye and assessment of its antimicrobial activity

• Agri-food industry by-product contains huge reserves of natural dyes.
• Optimization of extraction was done using mixture design.
• Colored extract and dyed fabrics provides an antibacterial activity.

The aim of this study was to investigate whether complexly constituted phenolics extracts from pepper waste may be utilized for the recovery of natural colored preparations.At first, different solvents mixture were compared to determine the best solvent for extraction of phenolic compounds from pepper by-product. The three solvents ethanol, acetone and water were used. The total phenolic content (TPC), the total flavonoid content (TFC) and the relative color strength (K/S) were studied using a simplex-centroid design. Acetone–water (68–32%) with 224 mg/L for total phenolic content and acetone–water (61–38%) with 0.446 mg/L for total flavonoid content were the best solvent mixtures for the extraction.The colored extract of pepper by-products was applied on woolen fabrics to investigate the dyeing characteristics and antimicrobial efficacy against common human pathogens such as Pseudomonas aeruginosa and Staphylococcus aureus. The results indicate that extract can be applied on woolen fabrics to produce colored clothing and textiles with acceptable antimicrobial properties.