Department of Food Science, Faculty of Science, University of Copenhagen, Rolighedsvej 26, 1958 Frederiksberg C, Denmark.
Arla Foods Ingredients Group P/S - Discover R&D, Department of Technology and Functionality, Sønderupvej 26, 6920 Videbæk, Denmark.
Food Chem. 2021 Jun 30;348:129145. doi: 10.1016/j.foodchem.2021.129145. Epub 2021 Jan 19.
Protein modifications in liquid infant formula (IF) have been widely studied, but distinguishing between heat- and storage-induced structural changes remains challenging. A generic liquid IF was subjected to direct or indirect UHT treatment and stored at 40 °C up to 180 days. Colour and pH were monitored and structural changes were characterised by dynamic light scattering, SDS-PAGE and centrifugal field-flow fractionation (FFF) coupled with multi-angle light scattering (MALS) and UV detectors to evaluate whether heat-induced differences would level out during storage. Both direct- and indirect UHT treatment led to structural changes, where the higher heat load of the indirect UHT treatment caused more pronounced changes. Indications were that storage-induced changes in pH, browning and non-reducible cross-links were not dependent on UHT treatment. However, FFF-MALS-UV analysis allowed characterisation of complex aggregates, where structural changes continued to be most pronounced in indirect UHT treated samples, and different storage-induced aggregation behaviour was observed.
液态婴儿配方食品（IF）中的蛋白质修饰已被广泛研究，但区分热诱导和储存诱导的结构变化仍然具有挑战性。对通用的液态 IF 进行直接或间接的超高温处理（UHT），并在 40°C 下储存长达 180 天。监测颜色和 pH 值，并通过动态光散射、SDS-PAGE 和离心场流分级（FFF）结合多角度光散射（MALS）和 UV 检测器来表征结构变化，以评估在储存过程中热诱导差异是否会趋于一致。直接和间接 UHT 处理都会导致结构变化，其中间接 UHT 处理的更高热负荷导致更明显的变化。有迹象表明，pH 值、褐变和不可还原的交联的储存诱导变化与 UHT 处理无关。然而，FFF-MALS-UV 分析允许对复杂的聚集物进行表征，其中结构变化在间接 UHT 处理的样品中仍然最为明显，并且观察到不同的储存诱导聚集行为。
