Abstract
This study explored the use of X-ray computerizedmicrotomography (micro-CT) and confocal Ramanmicroscopy to provide complementary informationto well-established techniques, such as confocal laserscanning microscopy (CLSM), for the microstructuralcharacterization of cheese. To evaluate the potentialof these techniques, 5 commercial Cheddar cheesesamples, 3 with different ripening times and 2 withdifferent fat contents, were analyzed. Confocal laserscanning microscopy was particularly useful to describedifferences in fat and protein distribution, especiallybetween the 2 samples with different fat contents. Thequantitative data obtained through image analysis correlatedwell with the nutritional information providedin the product labels. Conversely, micro-CT was moreadvantageous for studying the size and spatial distributionof microcrystals present within the cheese matrix.Two types of microcrystals were identified that differedin size, shape, and X-ray attenuation. The smallest,with a diameter of approximately 10 to 20 μm, weremore abundant in the samples and presented a moreuniform roundish shape and higher X-ray attenuation.Larger and more heterogeneous crystals with diametersreaching 50 μm were also observed in scarcer numbersand showed lower X-ray attenuation. Confocal Ramanmicroscopy was useful not only for identifying thedistribution of all these components but also allowedcomparing the presence of micronutrients such as carotenoidsin the cheeses and provided compositionalinformation on the crystals detected. Small and largecrystals were identified as calcium phosphate and calciumlactate, respectively. Overall, using micro-CT,confocal Raman microscopy, and CLSM in combinationgenerated novel and complementary informationfor the microstructural and nutritional characterizationof Cheddar cheese. These techniques can be used toprovide valuable knowledge when studying the effectof milk composition, processing, and maturation on thecheese quality attributes.
NETL
NSTL
Elsevier