Shelf life extension of white mushrooms (Agaricus bisporus) by low temperatures conditioning, modified atmosphere, and nanocomposite packaging material

In this work, we have explored a new integrated approach for the shelf life extension of button mushrooms (Agaricus bisporus). The effect of temperature (4 °C and 25 °C), packaging configuration (PET/coating/LLDPE oxygen barrier material over conventional PVC stretchable film), and modified atmosphere (15% O2/5% CO2/80% N2 over air) were monitored during 10 days of storage. The influence of a chitosan coating deposited on the cap surface was also investigated. Temperature was the most important factor in preserving the quality attributes of mushrooms over time. The test material had a positive impact on weight loss, cap opening percentage, and firmness of mushrooms compared with the control film (∼1.0% versus ∼7.1%; ∼55% versus ∼65%; and ∼10.3 N versus ∼7.6 N, respectively), which was ascribed to the excellent and good oxygen and water vapor barrier properties of the new material, respectively. Mushrooms packaged under the modified atmosphere behaved decidedly better after a prolonged storage time of 22 days at 4 °C. Impressively, after this extended temporal window, the mushrooms looked freshly packed by fully recovering their original color. We explained this striking observation in consideration of the oxygen that permeated the package during these additional 12 days of storage, which would have promoted a gradual resumption of respiratory activity in the overall metabolism of the mushrooms after the “freezing” effect of the rich-CO2 atmosphere inside the package.