The hard milk fat (HMF) fraction of milk fat was isolated via dry, thermal fractionation, followed by a solvent washing process. The resulting HMF crystals were visibly free of entrapped liquid fat, and subsequently characterised by thermal analysis, X-ray diffraction, and electron microscopy. The HMF crystals were found to be mostly β′ and β′₂ crystalline structures, with a lamellar thickness of 42.7–44.1 Å. Additionally, crystal size was determined to be ≥1 μm in length and 0.4–1 μm in width. Atomic force microscopy (AFM) was used to further characterise the HMF crystals. AFM enabled 3D mapping and visualisation of crystal layering, as well as simple determination of layer thickness (∼4.2 ± 0.8 nm); a value in close agreement with the results obtained via X-ray analysis. The AFM characterisation approach provides a simple method of characterising HMF crystals, without suffering the limitations of other widely used techniques.

乳脂的硬乳脂（HMF）馏分通过干燥，热分馏和随后的溶剂洗涤过程进行分离。所得的HMF晶体明显不含夹带的液体脂肪，随后通过热分析，X射线衍射和电子显微镜表征。羟甲基糠醛的晶体被发现是大多β'和β' ₂晶体结构，层状厚度为42.7–44.1Å。此外，晶体尺寸确定为长度≥1μm，宽度≥0.4–1μm。原子力显微镜（AFM）用于进一步表征HMF晶体。原子力显微镜可实现晶体分层的3D映射和可视化，以及简单的层厚度确定（〜4.2±0.8 nm）；与通过X射线分析获得的结果非常一致的值。AFM表征方法提供了一种表征HMF晶体的简单方法，而不受其他广泛使用的技术的限制。