Effects of Some Preservation Methods on the Nutrient and Mineral Compositions of Three Selected Edible Mushrooms

The global commercial mushroom production today is increasing yearly. To enhance the supply, many food processing industries normally provide a wide range of canned and processed edible mushroom products such as frozen, sterilized, dried, pickled, marinated and salted mushrooms in forms of mushroom powder, paste, concentrates and extracts. This study was therefore aimed at investigating the effects of popular preservation methods on the nutrient and mineral compositions of three selected oyster mushrooms of economic importance (Pleurotus ostreatus, Pleurotus florida and Pleurotus sajor-caju). Fresh mushroom samples were purchased from mushroom farms; each mushroom was shared into five different groups and processed as fresh, refrigerated, sundried, oven dried and micro-wave dried groups, they were thereafter analyzed for nutrient and mineral compositions. The results obtained revealed that the preservation method had significant effects on the nutrient and mineral compositions of the mushroom samples. Notably, the lowest weight values were obtained from the sundried mushroom samples while the highest value was obtained from the fresh samples. The microwave mushroom samples were richer in nutrient and mineral compositions as compared to the other three preservation methods but in all lower than the fresh samples. It is therefore concluded that the preservation methods had effects on the nutrient and mineral contents of mushrooms. However, if there is need for preservation of excess mushrooms, preservation through micro-wave drying is recommended best among the four processing methods for mushrooms preservation since it was able to retain the highest value of protein in all the studied mushrooms.