Simulation And Experimental Study On Drying Of Turpan-Free White Grape

Xinjiang is one of the main producing areas of high-quality grapes in China.Turpan is one of the main grape producing areas in Xinjiang,and the quality of grape produced by this area is well-known at home and abroad,especially the quality of seedless white grapes.Fresh seedless white grape is thin skin and succulent so that it is not easy to transport.And it is not easy to store in cold storage or atmosphere for a long time.So the 1/3 production of fresh grape in Turpan is for sale by growers,and 1/3 is for processing to beverages,canned products by processing enterprises,1/3 is for drying to get long-term storage and sales.The main drying method of Turpan Seedless White Grapes is airing room.This drying method is simple,low cost,and no other harsh conditions,so it is widely used by local farmers.However,health,quality and other aspects cannot be guaranteed that affect the price of farmers sales.At the same time,the pretreatment process of airing room,drying speed,as well as other qualities,not only affect the quality of raisins,but also impact on the drying cost of raisins.Therefore,basis of desiccant and airing room using by farmers,this article conducted systematic experiment research to select the pretreatment technology,the hanging way of grape,and the structure of the airing room,as well as the drying control environment.The drying process and quality index of raisins were obtained by using the image monitoring means.The correlation between drying factors and quality indexes of grape was analyzed to obtain the optimal factors and conditions for seedless white grape.And then this paper provides some suggestions for the drying,selection and improvement of the non-seedless white airing room for farmers,and lays a foundation for the sustainable development of the raisin industry.The main research contents,research methods and conclusions are as follows,(1)To get drying characteristics of seedless white grape in different distribution density and pretreatment condition.3 kinds of distribution density and 13 kinds of fresh grape pretreatment methods were used to evaluate the optimum hanging grape density and pretreatment method with the indexes of drying rate and green grade rate.The results shown that,the distribution density has a direct effect on the drying rate and quality of seedless white grape,and the drying rate is the fastest when the density of the hanging string is 0.75 times the density of the peasant household.It was analyzed for the drying index of 13 different pretreatment groups.After the pretreatment drying group,the drying rate is much higher than treatment of naturally-dried grapes with good quality.The best treatment group was 3% the drying agent and 4.5g potassium carbonate plus 0.6g/100 ml of the mixed liquid.And it can be made decision that the olive oil in the dry process can preserve the color of grape.(2)To get effects of different structures of airing room on the dry quality of seedless White Grapes.Experiments were conducted to verify the difference in drying effect under the conditions of the same elevation and air-bathing trend by using different airing room material,such as solid brick,hollow brick,hang shed several kinds of airing room.The results shown the air-enclosed solid brick and hollow brick structures are superior at both drying rate and drying quality.And the better effect of the brick is related to the heat transfer effect of this material.(3)To get the influence of different air-environment and additional air supply conditions on the dry quality of seedless white grape.The direction experiments of airing room were conducted with the same material and dimensions.And at the same time,the air flouring speed was changed to get the best conditions of grape drying.The results showed that the drying rate was faster and the quality was better with the long side of the airing room as the windward side,but there was no significant difference in drying rate of grape for different room in the same area,which was related to the local wind power during the drying process.And the drying time was shortened by half when the air speed of airing room was magnified to two times.(4)To select drying conditions and simulate fluid movement of seedless white grape.Combined with the measured drying process data of wind speed,temperature and humidity and measurement instrument in the air airing room,the fluid simulation was built using fluid simulation software.And better temperature for drying grape is of 42℃,humidity is 30.1% RH,which can provide the reference basis for the future development of mechanical drying equipment.(5)To get optimum parameters and conditions in drying process of seedless white grape.Through orthogonal test,it can be concluded that the best parameters for drying of seedless white grape are as follows,pretreatment is of 3% concentration of dry agent for grape treatment,hanging string density is 1:0.75 density,the long edge of the room is of the windward side,airing room material is hollow bricks.