芒果玻璃化转变与状态图研究  

Glass Transition and State Diagram of Mango

作　　者：赵金红[1,2] 朱明慧[1,2] 温馨[1,2] 姜云栋 康佳琪[1,2] 倪元颖[1,2] 

机构地区：[1]中国农业大学食品科学与营养工程学院,北京100083 [2]中国农业大学国家果蔬加工工程技术研究中心,北京100083

出　　处：《农业机械学报》2015年第4期226-232,共7页Transactions of the Chinese Society for Agricultural Machinery

基　　金：'十二五'国家科技支撑计划资助项目(2011BAD39B00)

摘　　要：研究了25℃下芒果的吸附等温线,实验数据采用GAB模型进行非线性拟合,结果表明芒果的吸附等温线呈'J'型,其单分子层干基含水率为0.107 g/g。芒果的状态图由冻结曲线、玻璃化转变温度曲线和最大冻结浓缩状态组成,其中冻结温度和玻璃化转变温度由差示扫描量热仪(DSC)测量得到。冻结温度和玻璃化转变温度的实验数据,分别采用Clausius-Clapeyron方程和Gordon-Taylor方程进行非线性拟合。实验结果显示,最大冻结浓缩状态时的固形物湿基质量分数为84%,在此状态下的玻璃化转变温度为-52.9℃。状态图的建立能够预测芒果贮藏过程的稳定性,并且能够提供最适干燥或冷冻加工条件。Sorption isotherms of freeze-dried mango （ the data were modeled by GAB model. A J-shaped variety Tainong No. 1 ） were determined at 25℃ and sorption isotherm of mango was presented and the GAB monolayer moisture contents were observed to be 0. 107 g/g. The unfreezable and freezable water contained in freeze-dried mango was examined to develop the state diagram. The state diagram of mango was developed using glass transition line （glass transition temperature vs solids content）, freezing curve （initial freezing point vs solids content） and maximal-freeze-concentration condition. Freezing points and glass transition temperature were measured by differential scanning calorimetry （DSC） as a function of water content. Freezing points were fitted according to the Clausius-Clapeyron model and the parameter E was determined as 0. 071 by using non-linear optimization technique. Glass transition was fitted to Gordon - Taylor model. The constants T s and k were estimated as 15.7℃ and 4.42, respectively. Glass transition increased with the increase of solids content, which was due to the plasticizing effect of water in mango solids. Freezing points decreased as total solids content increased. The maximal-freeze- concentration condition was calculated to be at a solid content of 84% with characteristic temperature of end point of freezing （ T＇m） being - 32.8℃ and characteristic glass transition temperature （T＇g） being -52.9℃. These characteristics revealed that the quantities of unfreezable water were 0. 16 g/g indicating the amount of reactive water. The state diagram of mango can be used in evaluating the storage stability as a function of temperature and moisture content. Moreover, it can also be used to design drying and freezing processes.

关 键 词：芒果 玻璃化转变 状态图 差示热量扫描仪 

分 类 号：TS255.3[轻工技术与工程—农产品加工及贮藏工程]