冷冻及微波干燥牡蛎制品的吸附等温线及玻璃化温度  

Water Sorption Isotherms and Glass Transition Temperature of Freeze-dried and Microwave-dried Oysters

作　　者：颜栋美[1] 侯金东[1] 余炼[1] 

机构地区：[1]广西大学轻工与食品工程学院,广西南宁530004

出　　处：《食品科学》2013年第21期91-95,共5页Food Science

基　　金：广西自然科学基金项目(0991033)

摘　　要：应用静态调整环境湿度法研究采用冷冻干燥和微波干燥方法进行干制的牡蛎制品在25℃的吸附等温线,并利用差示扫描仪测定其玻璃化温度。结果表明:干燥牡蛎的平衡水分随着水分活度(a w)的升高而增加,BET和GAB模型对吸附等温线的拟合度都很好;水作为塑化剂对玻璃化转变温度的影响是明显的,随着平衡水分的增加玻璃化转变温度显著下降,当牡蛎的干基水分含量为0.18kg/kg干基时,两种干燥方法得到的产品此时对应的玻璃化温度均在0℃以下。The water sorption isotherms of microwave-dried and freeze-dried samples of oyster at 25 ℃ were determinedby a gravimetric technique through static adjustment of environment, and the glass transition temperatures （Tg） weremeasured by differential scanning calorimetry （DSC）. The results indicate that the equilibrium moisture content of driedoyster increased with increasing water activity （aW）, and water sorption isotherms were fitted well with the GAB and BETmodels. Water as a plasticizer exerted a substantial impact on Tg, which showed a significant reduction with increasingequilibrium moisture content. Both dried samples containing 0.18 kg/kg water on a dry basis exhibited a Tg below 0 ℃.

关 键 词：牡蛎 冷冻干燥 微波干燥 吸附等温线 玻璃化温度 

分 类 号：TS205.9[轻工技术与工程—食品科学]