Hibiscus sabdariffa natural dye extraction process with central composite design for optimal extract yield

Abstract

This study reports optimization of Hibiscus sabdariffa natural dye extraction process parameters with response surface methodology, which is aimed at developing a more suitable and standardized technique to extract active components from plant materials. Hibiscus sabdariffa dye extraction process parameters (temperature, time and feed materials) were optimized for high yield. The dye was extracted using locally fabricated combined dye extractor and dryer machine with throughput capacity of 4 g/min machine and extraction efficiencies of 78.61% and 63.77% respectively using solvent as the medium. Central Composite Design (CCD) of Response Surface Methodology (RSM) was employed to optimize the process parameters that resulted in optimal yield. Liquid chromatography revealed components typical of natural dye extracts. The equations and models generated from RSM revealed experimental correlation between the dependent and independent variables. The fitted quadratic model's analysis of variance (ANOVA) with F-value of 14.78 for the model indicates its significance as there is only a 0.01% probability that such a big F -value is attributable to noise. Additionally, this analysis shows significant model terms as P-values less than 0.05 was obtained. The FTIR result showed a characteristic plant dye absorption pattern with wavenumbers that ranged from 3377 to 1032 cm−1. Optimal extract yield of 68% was attained at the temperature of 100 °C for 60 min and 1 kg feed material through RSM. This study revealed that extraction temperature and time had a significant effect, while the amount of feed material had a slight effect on the yield. Therefore, natural dyes can be extracted from Hibiscus sabdariffa for a sustainable natural color dyeing approach practiced in the textile industries. The study created a sustainable method of using bioresources for economic growth and development. The findings on this study provided a foundation for the use of Hibiscus sabdariffa dye extract as alternative to conventional dyes that can serve as functional colors for the textile, food and pharmaceutical industries.