Yu Ming, Le Floch-Fouéré Cécile, Lee Jeehyun, Boissel Françoise, Jeantet Romain, Lanotte Luca
STLO, INRAE, Institut Agro, 35042 Rennes, France.
Foods. 2022 Feb 16;11(4):562. doi: 10.3390/foods11040562.
Dairy powders are mainly produced by droplet spray drying, an articulated process that enables the manufacture of high added-value goods with a long shelf life and well-preserved functional properties. Despite the recent advances, a full understanding of the mechanisms occurring at the droplet scale in drying towers and, consequently, of the impact of process parameters and processed fluid characteristics on the powder properties is far from being achieved. In the wake of previous studies based on a laboratory scale approach, in this work, we provided a global picture of the drying in droplets of dairy protein mixes, i.e., whey proteins and casein micelles, which represent crucial dairy powder ingredients. Using profile visualization and optical microscopy, we explored the shape evolution in droplets with a range of protein contents and compositions typical of commercial powder production. The observation favored the evaluation of the specific role of each protein on the evaporation dynamics, and led to the construction of a phase diagram predictive of the dry droplet shape starting from the characteristics of the initial protein dispersions. Our outcomes represent a further step shedding light on the paradigm linking the physics of drying at the microscale and the nutritional properties of complex dairy powders.
乳粉主要通过液滴喷雾干燥生产，这是一个复杂的过程，能够制造出具有长保质期和良好保存功能特性的高附加值产品。尽管最近有了进展，但要全面了解干燥塔中液滴尺度上发生的机制，进而了解工艺参数和加工流体特性对粉末性质的影响，仍远未实现。在以往基于实验室规模方法的研究基础上，在这项工作中，我们提供了乳蛋白混合物（即乳清蛋白和酪蛋白胶束，它们是关键的乳粉成分）液滴干燥的全局图景。通过轮廓可视化和光学显微镜，我们研究了具有一系列典型商业粉末生产中蛋白质含量和组成的液滴的形状演变。该观察结果有助于评估每种蛋白质对蒸发动力学的特定作用，并从初始蛋白质分散体的特性出发构建预测干液滴形状的相图。我们的研究结果代表了在将微观尺度干燥物理与复杂乳粉营养特性联系起来的范式方面又迈出了一步。
