Department of Food Science and Engineering, College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, China.
J Sci Food Agric. 2021 Apr;101(6):2542-2551. doi: 10.1002/jsfa.10881. Epub 2020 Oct 27.
Maltose is an essential derivative of starch. To understand the processability and stability of maltose-containing foods, material characterization of the phase and state transition from its amorphous state is required. Although the crystallization of amorphous maltose is well understood, few studies have reported the relationship between the crystallization and the glass transition temperature (T )-related molecular mobility. In this study, water sorption, crystallization, T -related α-relaxation, and the corresponding time factor for amorphous maltose and maltose / whey protein isolate (WPI) mixtures are measured at various water activity (a ) levels and 25 °C.
The water-additive principle for maltose / WPI mixtures was observed at a ≤ 0.440 at the molecular level, whereas the crystallization of amorphous maltose occurred at high a values (≥0.534). The crystal formation and crystallization kinetics of amorphous maltose were affected by water and WPI at a ≥ 0.534 and 25 °C, as determined by X-ray diffraction. The relationship between T and the water content was fitted by the Gordon-Taylor model, and its constant showed a compositional dependence for the maltose / WPI mixtures. The α-relaxation temperature of the amorphous samples decreased due to water plasticization, but increased with an increase in the WPI quantity. The Strength (S) value for amorphous maltose, which was a quantitative estimate of the compositional effects on molecular mobility, was based on the William-Landel-Ferry (WLF) equation.
The S concept exhibits considerable potential for application in controlling the crystallization of amorphous maltose and improving the processability and stability of maltose-containing foods. © 2020 Society of Chemical Industry.
麦芽糖是淀粉的重要衍生物。为了了解含麦芽糖食品的加工性能和稳定性，需要对其无定形状态的相态和状态转变进行材料特性分析。虽然无定形麦芽糖的结晶过程已得到很好的理解，但很少有研究报道结晶与玻璃化转变温度（T ）相关分子流动性之间的关系。本研究在不同水活度（a ）水平和 25°C 下测量了无水麦芽糖和麦芽糖/乳清蛋白分离物（WPI）混合物的水分吸附、结晶、T 相关的α松弛以及无定形麦芽糖相应的时间因子。
在分子水平上，观察到麦芽糖/WPI 混合物的水加合原理在 a ≤ 0.440 时成立，而无定形麦芽糖的结晶则在高 a 值（≥0.534）时发生。X 射线衍射表明，在 a ≥ 0.534 和 25°C 时，水和 WPI 会影响无定形麦芽糖的晶体形成和结晶动力学。T 与含水量的关系通过 Gordon-Taylor 模型拟合，其常数显示出麦芽糖/WPI 混合物的组成依赖性。无定形样品的α松弛温度由于水的塑化作用而降低，但随着 WPI 量的增加而升高。无定形麦芽糖的强度（S）值是对分子流动性的组成效应的定量估计，它基于威廉-兰德尔-费里（WLF）方程。
S 概念在控制无定形麦芽糖的结晶以及提高含麦芽糖食品的加工性能和稳定性方面具有很大的应用潜力。 © 2020 化学工业协会。
