This research investigated the effect of ultrasound (US) pretreatment prior to spray drying on the powder flow and moisture sorption behaviour of micellar casein concentrate (MCC). MCC produced from skim milk microfiltration was sonicated at energy intensity of 0 (control), 47 J/mL (S-2000), 62 J/mL (S-3000) and 76 J/mL (S-4000). The results revealed that US pretreatment significantly increased the average particle size (D50) from 82.46 μm to 100.73 μm and reduced the surface fat content from 19.2% to 13.8%, resulting in decreased basic flow energy, cake energy and cohesion. Besides, the US treated samples showed relatively poor ability to acquire the moisture from the atmosphere than the control. Protein structure analysis showed that α-helix decreased with enhanced US power, while β-sheet and surface hydrophobicity increased, implying hydrophobic groups were exposed and water sorption rate was impeded. As a result, US pretreatment can improve the powder flow and potentially reduce the negative effect of cake formation at high humidity.

本研究调查了喷雾干燥前超声 (US) 预处理对胶束酪蛋白浓缩物 (MCC) 的粉末流动和吸湿行为的影响。在 0（对照）、47 J/mL (S-2000)、62 J/mL (S-3000) 和 76 J/mL (S-4000) 的能量强度下对脱脂牛奶微滤产生的 MCC 进行超声处理。结果表明，US预处理显着增加了平均粒径（D50）从82.46μm到100.73μm，表面脂肪含量从19.2%降低到13.8%，导致基本流动能、饼能和内聚力降低。此外，美国处理的样品从大气中获取水分的能力比对照差。蛋白质结构分析表明，α-螺旋随着 US 功率的增强而减少，而 β-折叠和表面疏水性增加，这意味着疏水基团暴露出来，吸水率受到阻碍。因此，US 预处理可以改善粉末流动并潜在地减少在高湿度下结块形成的负面影响。