微波热风联合干燥工艺对枸杞品质和表面微生物的影响  

Effects of microwave-hot air drying process on quality and surface microorganism quantity of Lycium barbarum

作　　者：刘伟东 顾欣[1] 郭君钰 岳衡 徐强[1] 刘海成 慕松[2] 王鹤[2] Liu Weidong;Gu Xin;Guo Junyu;Yue Heng;Xu Qiang;Liu Haicheng;Mu Song;Wang He(School of Agriculture,Ningxia University,Yinchuan 750021,China;School of Mechanical Engineering,Ningxia University,Yinchuan 750021,China)

机构地区：[1]宁夏大学农学院,银川750021 [2]宁夏大学机械工程学院,银川750021

出　　处：《农业工程学报》2019年第20期296-302,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：宁夏回族自治区西部一流建设学科项目(NXYLXK2017B03);宁夏重点研发计划重点项目(2018BBF02004,2018BBF02019);国家自然科学基金项目(11262018)

摘　　要：为明确微波热风联合干燥工艺对枸杞品质和表面微生物数量的影响,该文检测了微波热风联合干燥和传统热风干燥2种工艺各加工阶段枸杞的主要品质指标(枸杞多糖、总糖、粗蛋白、粗脂肪)和表面微生物数量,并对2种工艺的加工效果进行了比较。结果表明,采用微波热风联合干燥工艺和传统热风干燥工艺加工的枸杞,多糖和总糖损失率差异显著(P<0.05),联合干燥工艺较传统工艺分别降低了15.44和11.06个百分点,仅为18.46%和20.98%;粗蛋白损失率差异未达显著水平(P>0.05),损失率分别为21.46%和20.12%;粗脂肪损失率的差异也不显著(P>0.05),分别为10.56%和12.29%。在杀菌率上2种工艺差异显著(P<0.05),联合干燥工艺为91.26%,传统工艺为82.25%。干燥前的脱蜡处理具有杀菌作用,可杀灭65.24%的表面微生物。干燥阶段完成后,联合干燥工艺的杀菌率为91.26%,较传统工艺的杀菌率提高了9.01个百分点。在模拟大肠杆菌污染枸杞的试验中,脱蜡后喷菌的枸杞经2种工艺加工,联合干燥工艺的杀菌率为83.21%,较传统热风干燥工艺提高了12.93个百分点。因此,微波热风联合干燥工艺较传统热风干燥工艺更多地保留了枸杞的营养成分,杀菌效果更好,有利于枸杞干果的品质和食品安全。但是,对脱蜡后大肠杆菌污染的果实,微波热风联合干燥工艺和传统热风干燥工艺均不能彻底灭菌,需进行工艺改进或结合其他灭菌方法进行处理。研究结果可为微波热风联合干燥工艺在枸杞加工中的应用和改进提供参考。In order to study the effect of microwave hot air drying on the quality and microorganism quantity of L.barbarum.In this paper,the microwave hot air drying method and the traditional hot air drying were used to dry L.barbarum.The main quality indexes of L.barbarum polysaccharide,total sugar,crude protein,crude fat were determined.The number of microorganism on the surface of L.barbarum was measured.Hot air drying refers to drying after alkali liquor dewaxing and hot air drying at a constant temperature of 50℃.Microwave hot-air drying means that the alkali liquor is dewaxed first and then dried,and the hot-air drying is carried out at a constant temperature of 50℃,and then dried by microwave(Power:215 W,microwave pulse ratio:1.67).When the moisture content reaches 80%,50%,30%and 10%,the samples were taken to determine the content of L.barbarum polysaccharide,total sugar,crude protein and crude fat.The total number of bacteria and Escherichia coli on the surface were determined.Staphylococcus aureus,Salmonella and Shigella were detected.The results showed that the loss rate of L.barbarum polysaccharide and total sugar was significantly different between microwave hot air drying and traditional hot air drying(P<0.05).Compared with the traditional process,the combined drying process reduced 15.44 and 11.06 percentage points,18.46%and 20.98%respectively.The loss rate of crude protein was 21.46% and 20.12% respectively,but the difference was not significant.The difference of crude fat loss rate was not significant,10.56%and 12.29%respectively.In terms of sterilization rate,there was significant difference between the two processes(P<0.05).The composite drying process was 91.26% and the traditional drying process was 82.25%.Dewaxing before drying could kill 65.24% of surface microorganisms.After drying,the bactericidal rate of composite drying process was 91.26%,which was 9.01 percentage points higher than that of traditional drying process.E.coli was used as the contaminating bacteria for artificial pollution test.

关 键 词：干燥 品质控制 微生物 枸杞 微波热风联合干燥 热风干燥 

分 类 号：TS255.36[轻工技术与工程—农产品加工及贮藏工程]