School of Food and Nutritional Sciences, University College Cork, Ireland.
Faculty of Agro-Industrial Technology, University Padjadjaran, Indonesia.
Food Res Int. 2017 Jun;96:121-131. doi: 10.1016/j.foodres.2017.03.029. Epub 2017 Mar 16.
Fundamental knowledge of physical state of materials gives practically important information for food, biological and pharmaceutical industry. Based on Williams-Landel-Ferry (WLF) equation, the strength concept was introduced. This concept provides a simple parameter, S, to express resistance of solids to flow above the glass transition temperature. To develop this approach, miscible trehalose-maltodextrin (0:100; 20:80; 40:60; 60:40; 80:20 and 100:0) systems with different ratios of components were used in the present study. Such systems represent various food products including infant formula and many nutritional formulations. Amorphous solids were prepared from 20% solids in water solutions by freeze-drying. Fractional water sorption analysis of trehalose-maltodextrin miscible systems allows control of water content at high water activities. Glass transition temperatures were measured by DSC. DMA and DEA in a multi-frequency mode allowed determination of corresponding α-relaxation temperatures at various structural relaxation times. Volume rheology gives structural relaxation time - temperature dependence for high water content systems. The strength showed linear dependence on maltodextrin concentration and its value decreased significantly with increasing water content in miscible systems.
材料物理状态的基础知识为食品、生物和制药行业提供了非常重要的信息。基于 Williams-Landel-Ferry（WLF）方程，引入了强度概念。该概念提供了一个简单的参数 S，用于表示固体在玻璃化转变温度以上的流动阻力。为了开发这种方法，本研究使用了不同比例成分的可混溶性海藻糖-麦芽糊精（0:100；20:80；40:60；60:40；80:20 和 100:0）系统。这些系统代表了各种食品，包括婴儿配方奶粉和许多营养配方。通过冷冻干燥，从 20%固体的水溶液中制备非晶态固体。对可混溶性海藻糖-麦芽糊精系统的水分吸附分析允许在高水分活度下控制水分含量。通过 DSC、DMA 和 DEA 在多频模式下测量玻璃化转变温度，可在各种结构松弛时间下确定相应的α松弛温度。体积流变学为高水分含量系统提供了结构松弛时间-温度依赖性。强度与麦芽糊精浓度呈线性关系，在可混溶性系统中，其值随水分含量的增加而显著降低。
