Research On Air-impingement Jet Dry Technology Of Bitter Almond

Almond is one of the Rosaceae plants.High nutritional value,unique taste and favorite make it become popular.Bitter almond is similar to sweet almond in nutrition ingredient,but the price is c heaper,which make it have a very important market value and research significance.Almond contains amygdalin,hydrocyanic acid and other toxic ingredients,the current industrial usually use water immersion method to decrease bitter,soaked after drying is an necessary industrial process and an important way to extend the storage period of almonds.The existing drying almonds are mainly natural drying and hot air drying,these drying methods are convenient,but there are some energy consumption and efficiency problems.Gas jet impingement drying is a kind of new drying technology which has been proved to improve heat and mass exchange rate and heat transfer efficiency,which can reduce drying time,improve product quality and reduce energy consumption.In this paper,gas jet impingement technique is applied to the drying of almonds,study the effects of characteristics of drying almonds on different air impingement drying conditions,explore the change regulation of moisture of almonds on drying condition,establish drying kinetics model.The changes of almond quality during drying at different drying temperatures(55、70。85。100 ℃)were studied.The main conclusions are as follows:(1)Air impingement drying of almonds is a falling rate drying process,air temperature,nozzles to the material trays distance and wind speed changes will all lead to the changes of drying curves and drying rate curves and moisture effective diffusion coefficient.(2)Page model is the most suitful model in six selected model;response surface regression page model parameters and quadratic regression equation of drying condition are credible,the testing condition can effectively predict moisture changes in the process of almonds drying.Using response surface to establish method of drying model parameters is feasible;Drying kinetics model can effectively describe the moisture changes of almonds in the air impingement drying process.(3)In the process of drying,with the extension of drying time,crude fat content increased,the drying air temperature rise,crude fat content is lower.The content of protein change little,say roughly,it decreased first then increased,drying air temperature increase,the protein content decreased,the higher the temperature,the greater the decline rate.RR tend rising first than downward.