Study On The Modified Atmosphere Preservation Technology Of Agaricus Bisprus

Agaricus bisporus is an edible mushroom that has been popular among consumers in recent years.It has delicious taste and rich nutritional value.However,due to the high water content and breath rate of Agaricus bisporus,it is easy to induce enzymatic browning.After harvested for1-3 days at room temperature,the mushroom will lose weight,shrink,and browning,and its commercial value and consumption will decline or even lose,which seriously restricts the production and sales of Agaricus bisporus.The objective of this study was to determine the optimal storage conditions for Agaricus bisporus,screening the optimal storage temperature and humidity for Agaricus bisporus,and to investigate the effects of different packaging materials on the sensory and physiological quality of Agaricus bisporus and then to find out the suitable air conditioning packaging storage conditions.The main conclusions are as follows:1.The weight loss rate,umbrella opening rate,texture,color,browning index,PPO activity,MDA content and breath rate of Agaricus bisporus were determined at different temperatures(1,4,7 and 25?).The results showed that the fresh-keeping effect of Agaricus bisporus was the best at 1°C.At this temperature,Agaricus bisporus had the lowest weight loss rate and the lowest hardness loss,could maintain good sensory quality and effectively inhibited polyphenol oxidase(PPO)activity.After storage of 15d,the opening rate was only 2%.The whiteness of Agaricus bisporus at 1°C was30.40%,which higher than that at 7°C,while the browning degree and the content of MDA were 27.29%and 33.58%lower than those at 7°C.The breath rate was kept low during the whole storage period,and the degree of cell oxidative damage was the lowest.2.The weight loss rate,texture,color,browning index,PPO activity,MDA content and soluble solids content(TSS)of Agaricus bisporus stored under different relative humidity(70%±5%,80%±5%and 90%±5%)were measured.The results showed that the weight loss rate and TSS content of Agaricus bisporus reached to the lowest level at RH 90%±5%,the whiteness decreased by 6.9%,and the hardness remained at a high level compared with RH 70%±5%,the PPO activity decreased by 41.5%and the MDA content decreased by 35.9%.Both of PPO and MDA were all effectively inhibited at 15d,and 90%±5%RH was beneficial to prolong the storage and preservation of Agaricus bisporus.3.Four different thickness of packaging materials(PE 0.03 mm,PE 0.06 mm,OPP0.03 mm and PA 0.09 mm)were used for packaging and storage preservation experiments.The weight loss rate,hardness,color,browning index,PPO activities,MDA contents,breath rate and gas composition in the package of Agaricus bisporus were measured at 1±1°C and 90%±5%relative humidity.The results showed that the packing treatment could effectively reduce the weight loss rate,inhibit the accumulation of MDA,increase the PPO activity,reduce the respiratory rate and maintain the hardness of the mushroom.Among the packaging materials,0.06 mm PE film had the best effect on the storage of Agaricus bisporus by significantly inhibiting the post-harvest respiratory intensity of Agaricus bisporus and delaying the arrival of respiratory peak.After storage for 16 d,the weight loss rate was only 1.78%.Compared with the initial storage,the whiteness of Agaricus bisporus was only decreased by7.84%,and the average hardness of Agaricus bisporus decreased by only 13.03%.Compared with the control group,at the end of storage,the MDA content was reduced by 39.82%and the PPO activity was decreased by 43.92%in the 0.06 mm PE group.In the 0.09 mm PA group with high barrier properties,the browning degree reached to the highest point,which was 38.4%higher than that of the 0.06 mm PE group,and lead to more serious oxidative damage.In summary,0.06 mm PE is more suitable for storage of Agaricus bisporus with the parameters of oxygen transmission rate at 2362cm³(m²·24h·0.1MPA)^-1and water vapor permeability at 2.167×10^-13g(m·s·Pa)^-1.4.The effects of modified atmosphere packaging with different O₂concentration(0%,5%,10%,15%,20%)and CO₂concentration(5%,10%,15%,20%,25%)on the storage quality of Agaricus bisporus were investigated.The experimental results showed that the Agaricus bisporus had the lowest weight loss,the highest whiteness and the lowest hardness loss,and maintain good appearance quality at 5%O₂concentration,10%-15%CO₂concentration.Three single factors(packing material,CO₂concentration and O₂concentration)were chosen to interrogated by L9(3³)orthogonal test,and the sensory evaluation was taken as the reference index.The best parameters were determined to be 0.06 mm PE film,8%O₂,15%CO₂.The optimized group(0.06 mm PE,8%O₂,15%CO₂)was compared with the unoptimized group(0.06 mm PE,air)and the control group(unpackaged).It was found that the hardness of the optimized group was better than that of the control group and had a lower degree of damage.At the end of storage,the soluble protein content and ascorbic acid content were increased by 1.20times and 2.23 times,respectively,and the polyphenol content was 75.80%of that in the control group.Compared with the unoptimized group,the whiteness increased by1.15%and the ascorbic acid content increased by 17.98%.The optimized group improved in appearance and nutrient composition,but the volatile flavor component was less effective than the control group.