Sugar-free aerated chocolate: Production, investigation of bubble features using X-ray computed tomography and image processing

In contrast to other imaging techniques, X-ray imaging does not destruct the internal structure of the sample being imaged. Furthermore, this technique is able to capture numerous images of the sample at a low slice thickness, which is almost impossible in other imaging techniques. In this study, sugar was replaced with inulin:maltodextrin mixtures at ratios of 25:75 (i25), 50:50 (i50), and 75:25 (i75). Then, nitrogen (N2 ) and carbon dioxide (CO2 ) were injected into the three mixtures as well as the sugar-containing sample (control) at pressures of 3, 4.5, and 6 bar to produce aerated chocolate. The images of the samples were captured using X-ray computed tomography (XCT). After processing, they were segmented using the Chan-Vese model. Image segmentation showed that the Chan-Vese method, compared with adaptive thresholding, was more able to segment the images and remove the noise. The bubble total volume (10440 ± 9206 mm3 ) and average diameter (1.30 ± 0.10 mm) of the control were larger than those of the other samples. The results also demonstrated that the sugar-free aerated samples had lower hardness than the corresponding unaerated ones. However, it was reversed in the case of the control. This research sheds light on the industrialization of the production of aerated chocolate and the application of XCT and image processing in the analysis of the microstructure of aerated products.