Research On Processing Technology Of Agaricus Bisporus Ready-to-eat Dishes And Shelf Life Forecast

Agaricus bisporus is very popular among consumers due to its nutrients and tastes.Ready-to-eat(RTE)dishes can meet the needs of modern people's life style because of its convenience.The development of a Chinese RTE dish of A.bisporus can not only meet the needs of consumers,but also increase the added value of A.bisporus and create higher economic benefits.However,problems such as browning,texture loss,and nutrient loss will occur when A.bisporus are fried at high temperature in Chinese style.Thus,according to the production process of RTE dishes,pretreatment of A.bisporus,frying parameters and establishment of shelf-life prediction models was studied.The main results are as follows:1.Effects of low-temperature blanching,high-temperature blanching and steam blanching on the moisture content,shrinkage,hardness,browning degree,PPO and POD enzyme activities of fresh mushrooms was compared.Results showed that positive effects of enzyme deactivation ware occurred after steam blanching and high-temperature blanching,however,a significant of high shrinkage rate and decrease of hardness was observed as well.After low-temperature blanching,A.bisporus shrinkage rate is 2.73%,browning degree and PPO enzyme activity is reduced by 34.80%,and90.73% respectively.Moreover,results of study focusing on the effects of different blanching factors on the L*value,hardness,appearance and nutritional components of A.bisporus revealed,results showed that blanching or ultrasonication of fresh mushrooms will reduce the L*values and hardness of A.bisporus after frying.Increase of L*and hardness,as well as the alleviation of mushrooms after frying,and reduction of nutrient loss was found after low-temperature blanching combined with ultrasonic dipping.Through orthogonal experiments,the optimal pretreatment process was optimized as 3 g/L citric acid and 10 g/L calcium chloride immersion solution,blanching at 65?for 10 min with 500 W ultrasonic immersion,optimized The comprehensive score of A.bisporus in dishes increased by 16.13%.2.Effect of different frying time and frying temperature on the flavor of A.bisporus in RTE dishes was compared.Electronic nose,ion transfer chromatography,and fatty acid detection were utilized to evaluate the aroma of A.bisporus.Characteristic flavor of mushrooms such as 1-octen-3-ol and 2-octanal were increased in accordance with butyric acid and linoleic acid content with the increase of frying time and temperature.Electronic tongue,soluble sugar(alcohol),free amino acids,taste nucleotides,and organic acid detection were utilized to evaluate taste.The results showed that after fried at 180?for 4 min,the content of soluble sugar(alcohol)and Glu is higher than any other groups,however,the content of organic acid is the lowest.From witch the frying process was confirmed to 180?for 4 min.3.Molds,yeasts and specific pathogenic bacteria such as E.coli,Staphylococcus aureus,Salmonella,and Listeria monocytogenes were undetected after the RTE dishes were sterilized by circulating steam(100?,20 min).The total number of colonies within 30 days was far below the limit standard.Under the storage temperature of 30and 40?,the color value,hardness,p H,volatile base nitrogen,acid value and peroxide value of the dishes were measured and the Q₁₀model was fitted.With storage time increasing,the decrease of total color value and the p H was found,and the increase of TVB-N,AV and POV was observed.Correlation analysis found that p H value is a key index affecting the shelf life of RTE dishes.According to the prediction of Q₁₀ shelf life model,the theoretical shelf life of RTE dishes sterilized by circulating steam at 4?and 25?is 167 and 80 d respectively.