Study On Change Of Formaldehyde Content And Quality In Lentinus Edodes During Storage And Process

Lentinus edodes is nutritious and delicious,and is medicine edible mushroom.It is widely popular among people.However,in recent year "Lentinus edodes formaldehyde incident"has attracted widespread attention.The influence of nanocomposite packaging on formaldehyde content and quality in the precess of storage of Lentinus edodes and the influence of different drying methods and soaking process on formaldehyde content and quality of Lentinus edodes were studied in this paper.The main results were as follows:1 Lentinus edodes was treated by nanocomposite packaging,polyethylene(PE)packaging at 4 °C for 15 days.weight loss rate,respiratory intensity,relative conductivity,soluble sugar,soluble protein,GGT activity,C-Slyase activity,formaldehyde of Lentinus edodes were measured at regular intervals.Results showed that after 15 days of storage at 4?,weight loss rate,respiratory intensity,relative conductivity,GGT activity,C-Slyase activity,content of formaldehyde of Lentinus edodes packaged with the nanocomposite packaging were 0.331%,199.80 mg/(kg-h),5.97%,16.75 U/g,489.86 U/g and 6.24 mg/kg,respectively,which were inferior to that of ordinary polyethylene packaging.While soluble sugar and soluble protein of Lentinus edodes packaged with the nano-packaging were 7.50 g/kg,9.37 g/kg,which showed an enhancement of 12.11%,5.40%,compared with that of ordinary polyethylene packaging.Nano-packaging could better maintain qulity of Lentinus edodes and control the content of formaldehyde effectively.2 Lentinula edodes was treated with hot-air constant temperature drying,hot-air variable temperature drying and microwave vacuum drying respectively,and their effects on formaldehyde content and quality of Lentinula edodes were studied.Results showed that formaldehyde content of Lentinula edodes treated with hot-air constant temperature drying was higher than that of Lentinula edodes treated with hot-air variable temperature drying.formaldehyde content of Lentinula edodes subjected to pretreatment followed by hot-air constant temperature drying and hot-air variable temperature drying was reduced significantly,but it exhibited poor sensory,higher shrink rate,lower rehydration rate,loss of soluble sugar and soluble protein.formaldehyde content of Lentinula edodes treated with microwave vacuum drying was low,and close to that of Lentinula edodes treated with subjected to pretreatment followed by hot-air drying.Lentinula edodes treated with microwave vacuum drying exhibited moderate rehydration rate and loose texture.Lentinula edodes subjected to pretreatment followed by microwave vacuum drying exhibited lower formaldehyde content,loss of soluble sugar and soluble protein,similar shrink rate and rehydration rate,compared with direct microwave vacum drying.The influence of different time of hot air drying with 50? and 65? on formaldehyde content of Lentinuela edodes.The results showed that formaldehyde content of Lentinula edodes was first increased and then decreased with the extension of drying time,and the change of formaldehyde content of Lentinula edodes was the same trends with GGT and C-Slyase activity.In the early stage of the drying,formaldehyde content of Lentinula edodes of 50°C hot air drying was lower than that of 65? hot air drying,however,in the late stage of the drying,formaldehyde content of Lentinula edodes of 50 ? hot air drying was higher than that of 65? hot air drying.3 Change of formaldehyde content in rehydration process of Lentinula edodes was studied.orthogonal array design were applied to establish best condition for formaldehyde removal.The results showed that the degree of influence on removal of formaldehyde was A(temperature)>B(ratio of solid to liquid)>C(time).the best condition for removing formaldehyde was found to be treatment with water at 70? for 60 min with a solid to liquid of 1:15.In this conditions,the removal ratio of formaldehyde was 62.87%.