Determination of Organic Acids in Edible Mushrooms by High Performance Liquid Chromatography

Abstract

A high performance liquid chromatographic method (HPLC) was developed for the determination of organic acids (oxalic, tartaric, formic, α-ketoglutaric, lactic, acetic, citric, pyroglutamic, succinic and fumaric) in edible mushrooms. Organic acids were extracted with hot water. The solution was applied to a DEAE-sephadex A-25 column (borate type 20mm i.d.×50mm). The column was washed with 100ml of water, and organic acids were eluted with 0.1N hydrochloric acid. Organic acids were separated by HPLC on a column packed with KC-811 (8mm i.d.×300mm) by using 0.1% phosphoric acid solution as a mobile phase, and on a column packed with ULTRON N-C₁₈ (4.6mm i.d.×50mm) by using 0.1M potassium phosphate, monobasic, solution (pH 2.2) as a mobile phase with detection at 210nm. The recoveries of organic acids on DEAE column chromatography at levels of 75 to 1000μg were in the range from 80% to 110%. By using this method six commercial samples were analyzed. Eleven kinds of organic acids were identified. There were remarkable differences in the distribution patterns of organic acid compositions among the different species of edible mushroom.