Nutritional and antioxidant properties of selected-commercial mushroom in Thailand

Mushrooms, which are basically fungi, have several varieties throughout the world. In Thailand, commercial mushrooms are uniquely distinctive taste and flavor as well as widely consume increasing as foods and medicine. The drying process can be used to prolong the storage time and improve a stabilizing property of mushroom. As in this study, the selected-commercial mushroom; Phoenic oyster mushroom ( Pleurotus sajor-caju ), Bhutan oyster mushroom ( Pleurotus eous ), Tree oyster mushroom ( Pleurotus ostreatus ), Abalone mushroom ( Pleurotus cystidiosus ), Shiitake mushroom ( Lentinula edodes ), Straw mushroom ( Volvariella volvacea ), and Black tree ear mushroom ( Auricularia auricula-judae ) were investigated for their proximate compositions, total phenolic content, antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and the inhibition of lipid oxidation by ferric thiocyanate colorimetric method (FTC). These include a fresh mushroom and a dried form using a hot air oven at 50±5 ° C until having 10±2% of final moisture content. The results showed that the fresh samples have a moisture contents ranging from 89.51% to 93.45% (p<0.05). Dried mushrooms have the high contents in protein (9.06%-39.48% dried weight) and fiber (13.93%-28.40% dried weight) but low in fat content (0.13%-1.76% dried weight) (p<0.05). According to the antioxidant properties, the fresh mushrooms contained 1.33-39.24 mg GAE/g dried sample of total phenolic contents, 19.9%-79.41% of DPPH radical scavenging activity and 72.22%-87.37% of lipid peroxidation inhibitory activity (p<0.05). Whereas the total phenolic contents of dried samples ranged from 4.27 to 92.82 mg GAE/g dried sample (p<0.05) with regards to the potent radical scavenging activity on DPPH radical (51.27%-91.18%), (p<0.05). Moreover, the higher inhibition of peroxidation in linoleic acid system was found in the dried form (41.92-78.54%) than that of fresh samples. In conclusion, the selected-commercial mushroom may have potential as natural antioxidants and be recommended in application for functional foods. The drying process using a low air is optimally alternative process for preserving the commercial mushroom properties and can extend its shelf life.