Effect of argon- And nitrogen-based modified atmosphere packaging on shiitake mushroom quality

The effect of modified atmosphere packaging (MAP) on shiitake mushroom quality was investigated using different types of gases (air, nitrogen and argon). The mushrooms were placed in a composite polyethylene-polyamide package, and then the package was evacuated, flushed with desired gas, and heat-sealed. The packaged mushrooms were stored at 5 and 15°C for 21 days. During storage, the color, texture, gas composition, weight loss, microorganism count and polyphenol oxidase (PPO) activity were measured. Carbon dioxide production, weight loss, color change, PPO activity, microorganism count and decline of hardness were more inhibited at 5°C than at 15°C. The MAP used did not affect the weight loss or microbial count. However, mushroom in the argon (Ar) MAP had the lowest carbon dioxide production followed by those in the nitrogen (N) MAP and then the air filled control packaging (C). At 15°C, the L∗ value of the mushroom gills in the Ar and N MAP maintained throughout the storage time. Of particular note, mushrooms in Ar MAP retained hardness at 5 and 15°C, unlike those of the control. PPO activity was inhibited by the Ar and N MAP at 15°C. Based on these results, the quality of shiitake mushrooms was best preserved during storage by the Ar MAP.