| [objective]The Pleurotus eryngii Browning problems existing in the drying process,the serious influence the quality of the products,and different maintain different drying methods on product quality.So the Pleurotus eryngii drying processing of color protection technology and the best way to dry,the Pleurotus eryngii industry development is of great significance.[method](1)Selected seven different concentrations of color-protecting to stable the color of fresh Pleurotus eryngii:L-cysteine(0.01%,0.02%,0.03%,0.04%,0.05%),Zinc acetate(0.1%,0.2%,0.3%,0.4%,0.5%)and EDTA-2Na(0.05%,0.1%,0.15%,0.2%,0.25%),Calcium chloride(0.02%,0.04%,0.06%,0.08%,0.1%),Ascorbic acid(0.1%,0.2%,0.3%,0.4%,0.5%),Sodium chloride(0.5%,1%,1.5%,2.0%,2.5%),Citric acid(0.1%,0.2%,0.3%,0.4%,0.5%).After drying,the color difference was determined by chromatic meter.Then we selected the optimal concentration of each stabilizer.Color-protecting with better effect,and then through the response surface optimization to get the best non-sulfite color protection formula of Pleurotus eryngii.(2)After color-protecting,the Pleurotus eryngii were died with hot air drying,far-infrared drying and vacuum freeze drying,The quality of products based on its recovery rate of water after drying,quality and structure characteristics index,Browning related enzymes’ activities,cell microstructure andvolatile components of GC-MS,explore its effect mechanism,and select the best dry method of Pleurotus eryngii.[results](1)The results showed that the optimal concentration of seven color-protectings are 0.03%L-cysteine,0.3%Zinc acetate,0.15%EDTA-2Na,0.06%Calcium chloride,0.3%Vitamin C,1.5%Sodium chloride,0.3%Citric acid,respectively by the single-factor experiment.Using the response surface optimization to select the best non-sulfur stabilizer.The color-protecting formula are 0.3%citric acid,1.03%sodium chloride,0.31%vitamin C,0.15%EDTA-2Na.(2)three dried methods effect on dry products was not significant on the color.Vacuum freeze dried Pleurotus eryngii rehydration with the shortest time about 2 min.Compared with hot air drying,far-infrared drying SOD,CAT,POD activity change difference was not significant,PPO activity increased significantly(P<0.01);Vacuum freeze drying SOD,CAT,PPO and POD activity were significantly increased(P<0.01).Compared with hot air drying,far-infrared drying samples after water decreased elasticity,viscosity,higher hardness,chewiness,but the differences were not significant;Vacuum freeze-drying higher viscosity,hardness,elasticity,chewiness decreased,the extremely significant difference(P<0.01).For cell microstructure observed,far infrared drying after cell deformation obviously,hot air drying times,vacuum freeze drying after cell deformation was relatively small.Though GC-MS analysis,contrast four different way under dry Pleurotus eryngii flavor ingredients,compared with the fresh Pleurotus eryngii,aldehyde material:except hexanal,trans-2-octene aldehyde,coconut aldehyde contents were significantly increased(P<0.01),all the other aldehydes were significantly decreased(P<0.01),and even disappear;Alcohols material:2,3-butanediol,hexyl alcohol contents were significantly increased(P<0.01),all the other alcohols were significantly decreased(P<0.01),and even disappear;ketone material:except 2-Undecanone Solution increased significantly(P<0.01),the rest of the ketones were significantly decreased(P<0.01),and even disappear;Ester substances:with the exception of octanoic acid ethyl ester contents significantly increased(P<0.01),the rest of the esters were significantly decreased(P<0.01)and even disappear;2-amyl furan,inosine after drying the contents significantly increased(P<0.01).[conclusion]the non-sulfur protect color can reduce the Pleurotus eryngii browning;Different drying methods on the Pleurotus eryngii quality and structure characteristic,enzymatic Browning related enzyme activities,microstructure and volatile components all have certain influence,compared with the hot air drying and far infrared drying,vacuum freeze drying effect is relatively small. |
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