Comparative studies on chemical parameters and antioxidant properties of stipes and caps of shiitake mushroom as affected by different drying methods

BACKGROUND: Shiitake, the second most cultivated mushroom, is famous for its high nutritional value and medicinal properties. In this study, various chemical parameters and antioxidant properties of caps and stipes of shiitake mushroom dried by different methods (freeze-drying, shade drying and hot air drying) were comparatively investigated by spectrophotometric assays, high-performance liquid chromatography, 1,1'-diphenyl-2-picrylhydrazyl assay, ferric reducing power assay and lipid peroxidation inhibition assay. RESULTS: The contents of amino acids, neutral sugar and total phenolics in stipes were higher than those in caps of shiitake, while caps showed advantages in terms of their contents of protein and eritadenine. The chemical parameters and antioxidant activities of shiitake were significantly affected by the drying method used. CONCLUSION: The contents of total phenolics, amino acids and neutral sugar in stipes were higher than those in caps of shiitake, which suggested that stipes were more nutritional than caps in some respects. Hot air drying at 50 degrees C resulted in high total phenolic, amino acid, uronic acid and neutral sugar contents and antioxidant activities, which could be useful for the application of shiitake and related products in the food industry. (C) 2013 Society of Chemical Industry