School of Food and Nutritional Sciences, University College Cork, Cork, Ireland.
J Sci Food Agric. 2011 Nov;91(14):2529-36. doi: 10.1002/jsfa.4379. Epub 2011 Mar 28.
Stickiness correlates with changes in mechanical α-relaxation properties and often results from glass transition and plasticisation of amorphous food components. In this study, milk solids with maltodextrins with different dextrose equivalents (DE9 and DE17) were analysed for glass transition (T(g) ), α-relaxation (T(α) ) and sticky point (SPT) temperatures using differential scanning calorimetry, dynamic mechanical analysis and a sticky point test respectively.
At the same maltodextrin contents, T(g) and T(α) were lower for milk solids with the higher-DE maltodextrin. Increasing maltodextrin contents gave T(g) , T(α) and SPT at higher temperatures, and the magnitudes of α-relaxations with high maltodextrin (DE9 and DE17) contents were less pronounced.
Stickiness was governed by glass transition and affected by skim milk/maltodextrin composition. Stickiness was reduced with increasing maltodextrin content as a result of maltodextrin miscibility with skim milk solids, particularly lactose, which changed the relaxation behaviour above the glass transition. The mixes of milk solids with low-DE maltodextrin may show improved dehydration characteristics and powder stability resulting from increased T(g) , T(α) and SPT.
粘性与机械α松弛特性的变化相关，通常是由无定形食品成分的玻璃化转变和塑化引起的。在这项研究中，使用差示扫描量热法、动态力学分析和粘性点测试分别分析了具有不同葡萄糖当量（DE9 和 DE17）的麦芽糊精的乳固体的玻璃化转变（Tg）、α松弛（Tα）和粘性点（SPT）温度。
在相同的麦芽糊精含量下，具有较高 DE 麦芽糊精的乳固体的 Tg 和 Tα 较低。随着麦芽糊精含量的增加，Tg、Tα 和 SPT 的温度升高，高麦芽糊精（DE9 和 DE17）含量下的α松弛幅度较小。
粘性受玻璃化转变的控制，并受脱脂奶/麦芽糊精组成的影响。粘性随麦芽糊精含量的增加而降低，这是由于麦芽糊精与脱脂奶固体（特别是乳糖）的混溶性改变了玻璃化转变上方的松弛行为。低 DE 麦芽糊精与乳固体的混合物可能会由于 Tg、Tα 和 SPT 的增加而表现出改善的脱水特性和粉末稳定性。
