果蔬真空-蒸汽脉动漂烫机的设计与试验  

Design and experiment of vacuum-steam pulsed blancher for fruits and vegetables

作　　者：巨浩羽[1] 肖红伟[1] 方小明[2] 刘嫣红[1] 张卫鹏[1] 程鹏[1] 高振江[1] 

机构地区：[1]中国农业大学工学院,北京100083 [2]中国农业科学院蜜蜂研究所,100093

出　　处：《农业工程学报》2015年第12期230-238,共9页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金项目(31201436)

摘　　要：针对现有漂烫机漂烫时蒸汽和物料之间存在空气间层热阻,蒸汽不能迅速向物料传递热量而导致的漂烫不均匀、装载量小等问题,设计了一种真空-蒸汽脉动漂烫机。该漂烫机由抽真空系统、蒸汽系统、漂烫罐体以及自动控制系统构成,抽真空系统可以及时去除漂烫罐体内冷空气和漂烫之后的蒸汽。采用计算流体力学软件Fluent对漂烫罐体内气流流场进行模拟,结果显示增加扰流板和扰流孔后内部流场均匀,计算值和模拟值最大相对误差为5.2%。以漂烫百合为例进行了漂烫机的性能验证试验,结果表明:真空-蒸汽脉动漂烫均匀性良好,百合片在60℃热风干燥时间一致为11h,干后色泽无显著性差异。干燥时间随漂烫时间和循环次数的增加而先减小后增大,随真空度的增加而增大。当真空度为10kPa,真空时间为5s,漂烫时间为30s时,循环3次百合漂烫后的干燥时间最短,色泽变化较小。该研究解决了现有蒸汽漂烫机存在的漂烫不均匀、装载量小等问题,为其后续推广应用提供了参考。Blanching is an essential thermal processing using hot water or steam to treat fruits and vegetables,which is often carried out prior to the preservation process like drying,canning and freezing.Blanching can effectively inactivate enzymes in products such as polyphenol oxidase（PPO） and peroxidase（POD） enzymes,which cause deterioration reactions,off-flavor and undesirable changes in color.Under the condition of blanching,fruits and vegetables can keep their original colors,flavors and nutritional ingredients.Hot water and steam are by far the most widely used blanching methods.However,the main disadvantage of hot water blanching is that it causes nutritional substances especially sugar,proteins,carbohydrates,vitamins and minerals lost into water because of leaching and diffusion.What＇s more,hot water blanching can also cause environmental pollution due to the release of waste water containing considerable amount of nutrients.On the other hand,the main problems of steam blanching are blanching uniformity and small load.It is reported that solid foods are surrounded by thin-layer air and water,and steam cannot pass through these barriers of air and water,which act as insulation against the steam.The nonuniform blanching is possibly due to the existing of thermal resistance between material and steam.The thermal resistance prevents steam from transferring heat to the material.In addition,the steam will be condensed due to the air of low temperature.Considering those reasons,the pulsed vacuum-steam blanching machine is designed.This machine consists of vacuum system,steam system,automatic control system and blanching body system.The cold air and water around the material and useless steam can be wiped out by vacuum system in time.Therefore,thermal resistance is removed and heat can be transferred to material directly.In order to ensure the uniformity of the internal flow field,the flow field of inner blanching body was simulated by computational fluid dynamic（CFD） software Fluent,and the steam jet struc

关 键 词：机械化 计算流体力学 设计 漂烫 

分 类 号：S126[农业科学—农业基础科学]