This study focused on the influence of some operative parameters of Pressurized Liquid Extraction (PLE) employed for the extraction of colorants from onion (Allium cepa) skin. Extractions were conducted at temperatures ranging from 50 to 150°C with pressure of 1000 psi and two extraction cycles of 15 min. The effect of two extraction solvents (distilled water and 0.1% HCl in methanol (v/v)) was examined. The separation and determination of anthocyanin was carried out by high performance liquid chromatography with diode array detector. Major anthocyanin compounds identified include cyanidin 3-glucoside, cyanidin 3-rutinoside and cyanidin chloride. Video Spectral Comparator (VSC) was used to measure the color quality of the extracts based on CIE system (International Commission on Illumination, Vienna). It was found that the type of extraction solvent and extraction temperature influenced the yield, color and the composition of anthocyanins extracted. Using pressurized solvent extractor, specific color can be obtained by manipulating the type of solvent and temperature of extraction.
A. Sharif, N. Saim, H. Jasmani and W.Y.W. Ahmad, 2010. Effects of Solvent and Temperature on the Extraction of Colorant from Onion (Allium cepa) Skin using Pressurized Liquid Extraction. Asian Journal of Applied Sciences, 3: 262-268.