Effect of high argon pressure and modified atmosphere packaging on the white mushroom (Agaricus bisporus) physico-chemical and microbiological properties

The effect of high argon pressure (HAP) combined with modified atmosphere packaging (MAP) processing on the physico-chemical and microbiological characteristics of white mushrooms were assessed during 15 days of storage at 4 degrees C. The comparisons between different samples showed, HAP samples exhibited the smaller rate of weight loss and higher increase in total flavonoid and protein contents. Weight losses after 15 days of storage were 2.3%, 3.8%, 4.8% and 7.6% for HAP, MAP, HAP-MAP and untreated mushrooms, respectively. Furthermore, MAP treatment showed smaller polyphenol oxidase (PPO, E.C. 1.14.18.1) activity during storage. PPO activity in white mushrooms increased during the 15 days of storage from initial activity of 1 009 U.min(-1)g(-1) to 2070, 2418, 2 976 and 3 174 U.min(-1)g(-1) corresponding to MAP, HAP-MAP, HAP and control treatments, respectively. MAP-FLAP treatment revealed beneficial effects on white mushroom colour, total phenol content and ascorbic acid content, and moderate effect on total flavonoid and polyphenol oxidase (PPO). All treatments were effective in retarding mushroom colour change. Thus, application of MAP-HAP could extend the storage life of white mushrooms to 15 days at 4 degrees C.