Application of deaerated water in extraction of colorants from dyer's saffron florets

摘要

The efficiency of the application of deaerated water that has no dissolved gases in extraction of colorants from dyer's saffron (Carthamus tinctorius L.) was examined. Dyer's saffron contains about 7% yellow colorants, saffrole yellow, and 0.3% red colorants, carthamine. Saffrole yellow must be removed completely from dyer's saffron before the carthamine extraction, because if saffrole yellow is present in carthamine-red dyeing, the resulting color is yellowish. Carthamine is one of the colorants that decomposes with heat. The application of deaerated water in the extraction of these two colorants was examined. With the extraction of saffrole yellow, the maximum absorbances of extract solutions are the same as those in air-present water. The rate constants in deaerated water are lower than those in air-present water. With the extraction of carthamine, the ratios of the maximum value of cumulative absorbance in deaerated water to those in air-present water are 124 ± 7% at 0°C and 118 ± 10% at 25°C.