The Quality Of Dried Products Of Microwave Vacuum Drying And Regulation Of Litchi Pretreatment Equipment Research And Development

As one of the southern characteristic fruits,litchi is delicious and nutritious.Litchi easily goes spoilage at indoor temperature after 72 h,so that deep processing of litchi is particularly important.It is widely used in processing and drying of litchi,the most common is the traditional hot air drying,freeze drying and microwave vacuum drying and hot air drying.Hot air drying of litchi pulp soft dark brown,and fresh lychee vary greatly,often considered the low end of lychee dry products.Freeze-dried lychee flesh high nutritional value was snow white,crisp and delicious tastes,often considered the high-end products of litchi.However,the high energy consumption and high cost of freeze-drying severely limits its application to litchi.Microwave vacuum drying as a new way of drying,drying good quality low energy consumption,the use of dried food processing in recent years more and more aspects.However,the current microwave vacuum drying equipment,there are uneven heating,microwave source heat damage,less material loading and other shortcomings,in order to improve the efficiency of dry litchi drying and drying efficiency,the development of new equipment is essential.Peeled lychee often require drying before,because lychee pericarp has a special structure,it will greatly limit the moisture is removed from the pulp.Litchi different sizes,it is difficult to carry out large-scale and efficient skinning,the current litchi peel design a wide range of principles are similar,it is difficult to achieve industrialization,then efficient and reliable litchi peeled machine design is particularly important.In this paper,the lychee pretreatment equipment and litchi microwave vacuum drying equipment were researched and researched and the quality of lychee dried products was controlled by microwave vacuum drying.The main conclusions are as follows:1.A new type of continuous litchi grading machine was designed by combining the physical and chemical characteristics of litchi with the idea of grading and then peeling.The device combines the beam blocking type grading mechanism and the peeling mechanism organically to make the beam blocking type grading mechanism to classify the lychee,and then use the principle of the first opening tear to make the peeling mechanism to peel the lychee.Can be completed litchi processing in the classification,orderly feeding,cut,peeled,fruit collection of five processes.Canachieve the continuous high efficiency of litchi grape and peel operation,but also to maintain the complete uniform form of lychee.Is conducive to the realization of litchi grading automated,easy to industrial production.2.A new type of microwave drying and vacuum drying is designed,which combines the waveguide and the wave source cooling device to solve the two problems of uneven microwave distribution and microwave damage.The material chamber is the intersection of the microwave chamber and the vacuum chamber,which can make the material not only subject to microwave radiation,but also in a vacuum environment.Layered design of the material plate on the one hand can be easily removed,on the other hand can make full use of the material room space.Modular cold trap design,so that the cold trap can be free according to the needs of dry loading and unloading,can effectively improve the efficiency of cold trap.The microwave vacuum drying equipment design clever,safe and reliable,to meet the high-quality materials,dry processing.3.The effects of microwave vacuum drying(MVD)on the chemical index of litchi and the antioxidation ability of litchi polysaccharides were studied.The effects of microwave vacuum drying(MVD)on the antioxidant capacity of polysaccharides were studied by animal experiment.Hypoglycemic effect.The results showed that the water content of different varieties of litchi was not obvious under the condition of microwave vacuum drying.The content of VC was the highest.The purity of MVD cinnamon was the highest.The antioxidant activity of crude polysaccharides was detected by DPPH radical and FRAP respectively.The results showed that Feizixiao had the strongest antioxidant ability.In addition,the oral glucose tolerance test showed that microwave vacuum dried litchi crude polysaccharide on normal mice to reduce the blood glucose is not obvious,but can effectively reduce the blood glucose concentration in diabetic mice.MVD Guiwei had the most significant effect on the decrease of triglyceride and total cholesterol in the blood of mice.