Influences of the packing and packed about physiochemical properties of edible mushroom Pleurotus ostreatus.

Objective. To determine the effect of different packings and modified atmospheres on the physiochemical properties of a comestible mushroom (Pleurotus ostreatus) in fresh state. Materials and methods. Mushrooms were stored at 4 degrees C during 15 days, using three different forms of packings: 1) Polyestiren foam with polyvinyl chloride film cover (commercial packing), 2) Polyethylene terephthalate with polypropylene bioriented film cover and 3) Polyethylene of low density film cover and three different atmospheres: 1) Air, 2) 100% N-2 and 3) 10% O-2, 10% CO2, and 80% N-2. After stored possible changes in the physicochemical variables (pH, acidity, degrees Brix, moisture, chlorides, color and texture were determined. Results. There was an effect of time, packing and atmosphere on the physiochemical properties of fresh mushrooms. The range of variations was considered acceptable due to the characteristics of the mushrooms, such as biological entity that continuous with their metabolic processes. The changes in color (Group1: commercial packing and Group 1: Air stored) were not very appreciable, for the observer in all groups. The texture presented a decrease in the mechanical resistance, these may be due to the possible fermentative processes and deterioration for the high metabolic rate. Conclusions. There was not an appreciable effect of packing and environmental atmospheric conditions on the physiochemical properties of the mushroom Pleurotus ostreatus. It was also found that the commercial packing is more practical by issues of production costs.