Extraction of natural dye from Gardenia and chromaticity analysis according to chi parameter

Various methods of extracting natural dyes have been studied because of the increase of eco-friendly, non-toxic natural dyes. In this study, the natural dyes extraction process was optimized using Gardenia jasminoides   Ellis containing crocin. Hansen solubility parameter values and chi parameter values (χ12)(χ12) of various organic solvents and crocin were calculated, and the extracted pigments were analyzed by experiments. Comparing to calculated values and analyzed values, the relevancy was found and the solvents yielding color close to the target color were selected. Four kinds of solvents (methanol, ethanol, 1-propanol, and 2-propanol) having color close to the target color were selected because their χ12χ12 values were small and their Hansen solubility parameter values were similar to the Hansen solubility parameter value of crocin. These selected solvents were each mixed with distilled water at various volume ratios, and the extraction process was conducted. The results showed that L,a,bL,a,b values closest to the target color were obtained when using 40–60 vol% of the solvents. Also, trends of χ12χ12 values and the color difference (ΔE*) values were well matched up with UV absorbance.