Confocal Raman microscopy is a promising technique to derive information about microstructure, with minimal sample disruption. Raman emission bands are highly specific to molecular structure and with Raman spectroscopy it is thus possible to observe different classes of molecules in situ, in complex food matrices, without employing fluorescent dyes. In this work confocal Raman microscopy was employed to observe microstructural changes occurring after freezing and thawing in high-moisture cheeses, and the observations were compared to those obtained with confocal laser scanning microscopy. Two commercially available cream cheese products were imaged with both microscopy techniques. The lower resolution (1 µm/pixel) of confocal Raman microscopy prevented the observation of particles smaller than 1 µm that may be part of the structure (e.g., sugars). With confocal Raman microscopy it was possible to identify and map the large water domains formed during freezing and thawing in high-moisture cream cheese. The results were supported also by low resolution NMR analysis. NMR and Raman microscopy are complementary techniques that can be employed to distinguish between the two different commercial formulations, and different destabilization levels.

中文翻译：

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共聚焦拉曼显微镜观察奶油干酪受冷冻影响的微观结构变化的适用性。


共焦拉曼显微镜是一种很有前途的技术，可以在最小限度地减少样品破坏的情况下获取有关微观结构的信息。拉曼发射带对分子结构具有高度特异性，因此利用拉曼光谱可以在复杂的食品基质中原位观察不同类别的分子，而无需使用荧光染料。在这项工作中，采用共焦拉曼显微镜观察高水分奶酪冷冻和解冻后发生的微观结构变化，并将观察结果与共焦激光扫描显微镜获得的结果进行比较。使用这两种显微镜技术对两种市售奶油干酪产品进行了成像。共焦拉曼显微镜的分辨率较低（1 µm/像素），无法观察到可能属于结构一部分的小于 1 µm 的颗粒（例如糖）。利用共焦拉曼显微镜，可以识别和绘制高水分奶油干酪冷冻和解冻过程中形成的大水域。低分辨率核磁共振分析也支持了该结果。核磁共振和拉曼显微镜是互补技术，可用于区分两种不同的商业配方和不同的失稳水平。