Study On Osmotie Dehydration And Combination Drying Of Chestnut

Yan Shan chestnut,with osmotic pre-treatment, were dried with hot air-drying or vacuum freeze-drying were studied.Osmotic dehydration and optimum process conditions,In order to different processing purposes chestnut flour to establish a news dehydration process-combination drying.Osmotic-hot air-drying and osmotic-vacuum freeze-drying are compared with hot air-drying and vacuum freeze-drying for affect of chestnut flour quality and evaluation of energy consumption.Osmotic dehydration is used for the partial removal of water from fruits and vegetables by immersion in the hypertonic solution at a certain temperature,that the osmotic pressure of the osmotic solute is the mass transfer driving force.During osmotic dehydration an impregnation process with the osmotic solute from the solution to fruits and vegetables takes place simultaneously at countercurrent with the water flow from fruits and vegetables,at same time accompanied with the leaching of a little soluble compounds of fruits and vegetables.Compared with others dehydration methods,osmotic dehydration not only eney savings,but also advantage of improve the organizational structure of the product and the of dried products.Nowdays osmotic dehydration as pre-treatment with osmotic solute for dried,preserved fruit and fruit juice concentrate.With the aim of optimum processing conditions that yield maximum water loss and minimum solid gain during osmotic dehydration of chestnut in solution of sugar or sugar and salt.Experimental results show that chestnut slices are improve the rate of water loss;Water loss rate and solid gain rate increases with the increase of the concentration of osmotic solution, concentration of osmotic solution is too viscosity to beneficial of dewater, and affect the flavor;Water loss rate increases with the increase of the temperature of osmotic solution,but final water loss of different temperature. Solid gain rate basic trend increases with the increase of the temperature of osmotic solution; Constant agitation is beneficial to water loss and no significant relationship with solid gain; Water loss rate and solid gain rate increases with the increase of the solution to sample ratio of osmotic solution,and water loss rate more than solid gain rate; Experiments were designed according to Central Composite Rotatable Design for maximum water loss and minimum solid gain during smotic dehydration.At this optimum point,water loss and solid gain were found to be23.94%,5.41%respectively during chestnut slices osmotie dehydration with sucrose and salt;Water loss rate and solid gain rate were found to be28.21%,6.63%respectively during chestnut slices osmotie dehydration with sucrose and salt.The comparison two osmotic solution that molecular weight and ion behavior has a great influence on water loss rate and solid gain rate.Chestnut slices were dried with hot air-drying or vacuum freeze-drying with osmotic dehydration pre-treatment.Study in the quality and enery consumption of chestnut flour with different dewater methods.Experimental results show that chestnut flour was preparation with osmotic dehydration-hot air-drying or Osmotic dehydration-vacuum freeze-drying are different than single of hot air-drying or vacuum freeze-drying,such as improve drying rate and rehydration of the chestnut slices,depressed water activity of the chestnut flour,the color unchallenged of chestnut flour,a litter caramel of the chenstnut slices surface,increase hardness of the chestnut slices,depressed final dried time of the chestnut slice.Combination drying are benefit for depressed of energy consumption and processing costs,extend of preservation,and improve of quality and economic benefits.