Optimized Analysis of Organic Acids in Edible Mushrooms from Portugal by Ultra Fast Liquid Chromatography and Photodiode Array Detection

Organic acid profiles of different mushroom species were obtained by ultra fast liquid chromatography, by means of photodiode array detector. The chromatographic separation was achieved using a SphereClone (Phenomenex) reverse phase C-18 column using an isocratic elution with sulphuric acid (3.6 mM) at a flow rate of 0.8 mL/min. All the compounds were separated in 8 min. The method was optimized using Agaricus bisporus sample and proved to be reproducible and accurate. Organic acid profiles were quite homogeneous for all mushroom samples; oxalic, malic and fumaric acids were the main organic acids; some samples also presented quinic and citric acids. Sarcondon imbricatus was the species that presented the highest total content (254.09 mg/g dry weight (dw)), while Bovista nigrescens presented the lowest concentration (1.33 mg/g dw). The high amounts of organic acids present in all the species may suggest that they could be related to the antioxidant activity found in these species and previously reported by us.