MODIFIED ATMOSPHERE PACKAGING OF COMMON MUSHROOM

Until recently, the films used for packaging fresh fruits and vegetables were not permeable enough to balance the high respiration rate of mushrooms. Consequently, modified atmosphere packaging (MAP) in sealed pouches or punnets was not appropriate for this commodity. Four microporous films in oriented polypropylene (OPP) and one film currently used to overwrap mushroom punnets (stretchable PVC) were tested. Mushroom punnets placed into pouches were stored at 4 and 10-degrees-C for 8 days. The influence of the modified atmosphere on the marketing quality of pre-packed mushrooms was assessed by measuring the external and internal colour, development stage, firmness and microbial growth. A mathematical model was used to predict the gas composition within the pouches at steady state as a function of the film properties and the characteristics of the plant tissues. The equation calculated from the simplified model shows a linear relationship between the reciprocal of O2 concentration at steady state, (1/x) at 10 and 4-degrees-C and the reciprocal of the film permeability, (1/PmO2).