Effects Of Dehydration Treatment On Quality And Flavour Of Lentinus Edodes During Post-harvest Storage

Lentinus edodos is not only a traditional Chinese edible fungus,but also the second largest edible fungus in the world.It has high edible and medicinal value,because the fruit has a unique flavor,loved by many people.Lentinus edodos is easily rotted under normal temperature for the high level of breathing intensitty coupled with their high moisture content and soft tissue.Lentinus edodos preservation period of storage under normal temperature for 2-4 d.Therefore,systematically study physiological changes and applicable storage technology of Lentinus edodos have a significant scientific value and social benefits.The physiologic biochemical changes of Lentinus edodos harvested during 20? storage after dehydration of 0 %,5 %,10 %,15 % and 20 % by heat pump were studied in this experiment.The effects of different dehydration treatment on sensory quality,physiological and biochemical,browning,taste and volatile components of Lentinus edodos during storage was determined,and the main results are as follows:(1)The dehydrating rate of lentinus edodes below 20% does not affect the sensory quality after dehydrating.The best condition of dehydration treatmentin in heat pump:the temperature is 30 °C,the relative humidity RH is 40%,and the placement is 45° to the plane(An angle of 135° with the wind).The water loss rate-time curve is y=-0.00000371x2+0.00204185x+0.00133802,R2=0.9993.The firmness of Lentinus edodos decreased during storage.Dehydration treatment can increase firmness,postponed the peak time of elasticity,chewiness and cohesiveness,maintain the sensory quality,and the storage time is positively correlated with the loss rate of Lentinus edodos.(2)Different treatment groups showed the peak time of breathing intensity during storage,and appropriate dehydration treatment(10 %,15 %)could postponed the peak time of respiratory intensity and reduced its peak value.10 %,15 % and 20 % dehydration treatment can postponed the peak of soluble protein content,slowed down the decrease of soluble sugar content and reduce the degradation of nutrients.(3)Appropriate dehydration treatment(10 %)could delay the occurrence of browning in Lentinus edodos in three days during storage.Inhibited PPO and POD activity,maintain high CAT activity,remove H2O2 and maintain the integrity of cell membrane,reduces the production of MDA,delayed phenolics degradation.delay the occurrence of browning,and keep the color.(4)The total content of volatile components had increased during storage and its after the dehydration treatment was higher than CK.The volatile components of the different treatment groups were similar,and the characteristic volatile substances were the same.So,dehydration treatment couldn't destroy the original flavor.Pro and Try were not detected in Lentinus edodos,and Try was only detected at sometime.After storage,the total content of umami amino acid and bitter taste amino acid were decreased,however,the total content of sweet amino acid was increased.Dehydration treatment will increase the peak value of EUC and showed that the intensity of flavor increased with the extension of storage time.Thedetermination results of taste of Lentinus edodos by electronic tongue showed that the sweetness,flavor and the saltiness were increased,and the sourness was decreased after storage.the intensity of bitterness not change significantly except for 20% dehydration treatment during the storage.(5)At the room temperature(20 ?)storage,considering the storage time,sensory quality,physiological and biochemical,browning,taste and volatile components and economic benefits during storage after different treatment,10 % dehydration treatment have a better performance than other treatment.