Microscale Surface Roughening of Chocolate Viewed with Optical Profilometry

Abstract

Microtopographical roughening and fat phase melting of milk chocolate subjected to three temperature cycles between 20 and 28, 30, 32, or 34°C were examined using optical profilometry and differential scanning calorimetry (DSC). Cycling to any of these temperatures did not lead to immediate visual bloom, though significant effects on microstructure and fat phase melting behavior were noted. The initial chocolate topography was lightly mottled and consisted of small asperities. DSC indicated the presence of form V crystals in control chocolates kept isothermally, with form VI crystals appearing with cycling to 30 and 32°C. The fat phase of the chocolates cycled to 34°C existed only in the form IV polymorph. As a result of cycling, the surface roughness of all samples increased, with the smallest rise seen with cycling to 28°C. Decomposition of the roughness into low and highfrequency components revealed a significant contribution of waviness (the low-frequency component) to overall roughness, particularly with cycling to 34°C. Furthermore, with the fat phase fully molten, the backbone structure consisting of the dispersed particulates also contributed to overall roughness. This study demonstrated that significant microstructural changes and deformation take place within chocolate as a result of temperature fluctuations prior to the onset of visible surface fat bloom.

Permeability evolution of propped artificial fractures in coal on injection of CO2

“…Fine sand paper (#400) to very fine cotton cloth with alumina powders from 0.3 μm to 0.05 μm were used to polish the coal surface (ASTM International D5671, 2011). Surface roughness was quantified by optical profilometry (Kumar et al, 2009;Rousseau et al, 2010). The split-cores were re-mated either without or with a uniform monolayer of 70-140 mesh proppant sand.…”

Permeability evolution in sorbing media: analogies between organic‐rich shale and coal

“…The cores were wrapped in aluminum foil to prevent any adsorption or diffusion of CO 2 through the rubber jacket during the permeability experiments. Surface roughness was quantified by optical profilometry both preand postexperimental sequences Rousseau et al 2010).…”

Textural and Physical Properties of Biorenewable “Waxes” Containing Partial Acylglycerides

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