Effect Of Pretreatment On The Quality Of Agaricus Bisporus

[Objective]In order to develop the deep-processing products of Aariczus bisporus,it is necessary to study the changes of Agaricus bisporus 's quality.Therefore,this experiment mainly was to study the effect of pretreatment on the quality of Agaricus bisporus,so as to provide some theoretical basis for the later processing.[Methods]Agaricus bisporu was heated at 75 ?,85 ? and 95 ? for 0.5 min,1 min,5 min,10 min,15 min or 20min,then we used the colorimeter to determine the color.The TPA was used to determine the hardness,elastic adhesiveness,cohesiveness and chewiness and adhesiveness.At last,screening the best temperature and time with comprehensive evaluation to maintain the quality and color of Agaricus bisporu.Then we used 0.7%citric acid,0.4%NaCl and 0.4%sodium ascorbate as the compound color fixative,and used 1%CaCl2 as the hardening treatment regent to handle the Agaricus bisporu under the best temperature and time.Scanning electron microscopy was used to observe the changes of tissue structure;the activities of PPO,POD,SOD,CAT and total sugar and total phenol were determined by chemical analysis;the volatile components was explored by GC-MS.[Results](1)With the increase of treatment temperature and time,the color difference value of Agaricus bisporu increased;the hardness,cohesiveness,chewiness and adhesiveness decreased with the prolonging of time,elastic value increased first and then decreased at 75 ??95 ?,the adhesion decreased with the prolongation of time;the optimum temperature and time of 95 ?5min were obtained by combining texture index and sensory evaluation score,therefore,it is suggested that the appropriate color and hardening treatment should be adopted to maintain the quality of the Agaricus bisporus.(2)Compared with the control group,after blanching,the structure of Agaricus bisporus fiber was more compact,but the fiber structure arranged loosely after the color protection and hardening with heat treatment,the results showed that the color protection and hardening treatment could improve the structure of Agaricus bisporus.Therefore,in the actual production,it should be carried out at 95 ? 5 min hot treatment after the color protection and hardening treatment.(3)Compared with the control group,the activities of PPO,POD,SOD and CAT significantly decreased after blanching(P<0.01);the color protection and hardening group with heated treatment,the activity of CAT significantly increased(P<0.01),the activity of POD decreased,the activity of PPO and SOD decreased,the differences were significant or extremely significant(P<0.05 or P<0.01);the activity of CAT increased significantly(P<0.01).It can be concluded that the color protection and hardening could restrain the activity of PPO and SOD,protect the activity of CAT,it is necessary to combine the relative changes of each enzyme to determine whether to carry out color protection and hardening and heat treatment.(4)Compared with the control group,the contents of total sugar and total phenol in the other two groups significantly decreased(P<0.05 or P<0.01),compared with blanching group,the total sugar content and total phenol content in the color protection and hardening group decreased,but the differences were not significant.The results showed that the color protection and hardening treatment had little effect on the total sugar and total phenolic content of Agaricus bisporus.(5)The volatile components in the control group,the blanching group and the curing group were 30,31 and 29 respectively.Compared with the control group,in the blanching group,the content of 4 aldehydes significantly reduced(P<0.01);2 alcohols increased,but benzyl alcohol decreased and the difference was extremely significant(P<0.01);5 esters increased,and allyI chloroacetate,benzoic acid methyl ester,2,5-eighteen carbon acid,methyl ester entirely disappeared;2 acids increased;the changes of ketone substances were not obvious.Other components such as tropilidene,2-pentylfuran,Methylpyraz:ine and 2,6-two methyl pyrazine increased,but 1-isopropyl-1-propylene and Allyl benzyl ether disappeared.Compared with the blanching group,in the color protection and hardening treatment group,the content of 4 aldehydes significantly increased,benzaldehyde significantly increased(P<0.01),2 aldehydes decreased,3-methyl butyl aldehyde decreased significantly(P<0.01);4 alcohols increased,hexyl alcohol and benzyl alcohol increased extremely significantly(P<0.01),6 alcohols decreased,mushroom alcohol decreased significantly(P<0.01);5 esters increased,3 kinds were disappeared;3 acidss increased,but 3-Aminoisobutyric acid was disappeared;3 ketone substances decreased and the differences were significant(P<0.05 or P<0.01),but 2-ethyl-1-ketone increased significantly(P<0.05),In addition,methylpyrazine increased significantly(P<0.01).The results showed that the treatment of color hardening and blanching had great influences on the volatile components of Agaricus bisporus.[Conclusions]Blanching treatment could affect the textural properties of Agaricus bisporus,enzymatic browning related enzymes,total sugar,total phenol and volatile matter content.The effects of color hardening on total sugar,total phenol,PPO and POD activity were not significant,but it has certain influences on volatile substances.