Comparative Quality Evaluation of King Oyster Mushroom as Affected by Unit Packaging Method during Simulated Export Shipment

Potential of consumer unit packaging was investigated for quality maintenance during export simulation in king oyster mushrooms (Pleurotus eryngii). Mushrooms were harvested in late May, precooled to 4℃ within 6 hours, and then packaged for shipping in two ways: 2 ㎏ bulk packaging in a polyethylene (PE) bag or three types of unit packaging methods such as 400 g in polypropylene film bag (PPB), 200 g on styrofoam tray + PE shrinkage film wrapping (STW), and 200 g in polyethylene terephthalate (PET) containers (PETC). For local distribution of bulk-packaged commodity, mushrooms were sorted again and packaged into 3 consumer units in the same way as for the initial shipping packages. Simulation of refrigerated container shipping was performed in a walk-in type pilot storage at 0.5℃ for 5 weeks, while local marketing simulation was carried out on the shelf at 7℃ for 7 days. During the shipment simulation, creation of modified atmosphere (MA) was substantial in 2 ㎏ bulk packages with low O₂ below 2% and high CO₂ over 15% whereas, in PPB and PETC unit packages, relatively higher O₂ concentrations were observed. On the shelf at 7℃, CO₂ concentrations rapidly increased in PPB and PETC packages despite the short marketing period. Overall marketability evaluated by off-flavor, browning, and texture rating was maintained at excellent level when 2 ㎏ bulk packaging in PE or unit packaging in PPB and PETC were used for shipment. In contrast, establishment of MA was very slight in STW packages during shipment and local distribution resulting in poor quality after export simulation. The results suggested that shipment using adequate consumer unit packaging is more practical and economically beneficial than using bulk packaging in the export program consisting of 5-week shipment and 7-day local distribution.