Abstract
As conditions of mushroom producing has the great effect on their mineral contents and quality of nutritional value and also consumption and cultivation of mushrooms has been increased remarkably in recent years in Iran , this research builds upon: Determination and comparing essential mineral contents: Iron, Copper, Zinc, Selenium, Calcium and Manganese as the nutritional value in mostly consumed brands of packaged Oyster mushrooms (Pleurotus ) samples purchased from Tehran markets and Investigation the effect of cooking method (raw, cooked, fried, micro waved), in mineral contents in Oyster Mushroom samples and find the best method of cooking. 880 samples from the 4 most famous brands of Oyster mushroom packaged were purchased in all different weight packaged available in market from creditable brands in Tehran, Iran in winter 2013 and 2014. The samples were analyzed by wet digestion method and standardized international protocols were followed for the preparation of material and analysis of the metal contents by Flame Atomic Absorption Spectrophotometer. Results revealed that even in the same season and same time of studying, there was a wide range of essential metal contents in different brands. The mean content of all studied essential elements in all samples would be decreased according to the microwaved cooking methods while frying method enhanced all of them. The reaction of Calcium content to microwaving was much higher than other elements (p_ 0.001