Study On Compound Preservation Technology Of Letinous Edodes

In this paper,the extraction technology of polyphenol oxidase from letinous edodes,enzymatic properties and the effect of several inhibitors on the activity of polyphenol oxidase in letinous edodes are studied.On this basis,the research on the effect of polyphenol oxidase inhibitor on the preservation of letinous edodes and the effects of two kinds of modified atmosphere preservation methods of silicon window and argon on letinous edodes are carried out and provide more theoretical foundation for the preservation of letinous edodes.The main results are as follows:The effects of pH,extraction time and PVPP content of phosphate buffer solution on the activity of polyphenol oxidase a studied by single factor experiment.On this basis,the orthogonal optimization experiment of three factors and three levels is designed to obtain the optimum conditions for extracting polyphenol oxidase from letinous edodes by homogenate extraction.The optimum conditions are:the pH of phosphate buffer solution is 6.7,the extraction time is 50min and the content of PVPP is 2.5%.Through the single factor experiments of ultrasonic treatment time,ultrasonic treatment temperature and the effect of solid-liquid ratio on polyphenol oxidase activity,the orthogonal optimization experiment of three factors and three levels is designed to obtain the optimum conditions of ultrasonic assisted extraction of polyphenol oxidase for letinous edodes.The optimum conditions are:ultrasonic treatment time is 180s,ultrasonic treatment temperature is 40 DEG C and solid-liquid ratio is 60%.The inhibitory effects of ascorbic acid,citric acid and lactic acid on the activity of polyphenol oxidase in letinous edodes are studied by single factor analysis.On this basis,according to the principle of Box-Benhnken center combination experiment,the response surface optimization experiment of three factors and three levels is designed to obtained the inhibitory effect of composite inhibitors on the activity of polyphenol oxidase of letinous edodes.The optimum condition are as follows:the content of ascorbic acid,citric acid and lactic acid arc 0.00g/L,10.00g/L and 2.00g/L,respectively.The condition of the inhibitor solution is used to preserve the letinous edodes.The results show that the browning degree of the inhibitor group is 7.18%lower than that of the noninhibitor group,the activity of polyphenol oxidase is lower by 8.98%,the content of total phenol is higher than that of,the content of Vc is higher than that of 14.52%,and the respiratory intensity is lower than 10.17%.It is obvious that inhibitor treatment can effectively inhibit the deterioration of letinous edodes and allow letinous edodes to maintain good sensory quality during storage.The effect of different silicon window area on the storage quality of letinous edodes with the gas composition of 10%O₂,10%CO₂,80%N₂ is analyzed.The result shows that the use of modified atmosphere with silicon window for preservation of letinous edodes,can well inhibit the increased degree of browning,polyphenol oxidase activity,control the total phenol content,decreased the content of ascorbic acid and can better reduce the respiration rate during storage period.The the letinous edodes browning is controled effectively and keeps the quality of letinous edodes.The siliconw indow area of 50cm,60cm² conducts the best preservation effect.Under the consideration of all the indicators and resource conservation,the silicon window preservation bag with area of 50cm² can be used for fresh keeping of letinous edodes.Effects of two kinds of packaging materials and different initial gas concentration on storage quality of letinous edodes shows that the using of argon gas can well inhibit the increased degree of browning,polyphenol oxidase activity,control the total phenol content,decreased the content of ascorbic acid,and can better reduce the respiration rate increased during storage period,the effective control of the letinous edodes browning,letinous edodes quality preservation.Compared with LDPE and PE two kinds of packaging materials in the application of the best group found that the use of LDPE as the packaging materials are better than PE.Experiment with different initial concentrations shows that when the LDPE is chosen as the packaging material,the optimum aeration ratioof OZ,CO₂,Ar and N₂ is 5%,5%,90%and 0%,respectively.