Confocal Raman microscopy has been shown to be a useful technique for investigation of white chocolate surfaces. The appearance of protrusions and pores, and the distribution of fat, sucrose, and milk powder at and below the surface of white chocolate pralines were investigated using confocal Raman microscopy. Raman horizontal and depth scans showed that the protrusions and pores continue at least 10μm into the chocolate shell and that some protrusions and channels mainly consist of fat, while some consisted of a fat layer, leaving a hollow space underneath. Further, the pores and their continuing channels consisted of nothing but air. These findings indicate that the protrusions might be connected to channels where we suggest a pressure driven convective flow of liquid fat from within the chocolate matrix that, depending on temperature, moves up to the surface or goes back into the matrix, leaving an empty pore with a shell of fat at the surface, which in some cases collapse and leaves a hollow pore and channel. Therefore, these findings support that the protrusions could be connected to oil migration in chocolate and, thus, further to fat bloom development.

Palm oil was hydrogenated in a single-phase mixture with propane and hydrogen. This was done in a small (0.5 ml), continuous fixed-bed reactor, using a 1% Pd/C catalyst. Temperature (65-135 °C), H2/TG ratio (4-50 mol/mol) and residence time (0.2-2.0 s) were varied systematically to assess the iodine value (IV) as a function of these three variables. The substrate concentration was 1 wt-%. The IV was dependent mainly on temperature and residence time. At 120 °C and a residence time of 2.0 s, full hydrogenation was achieved. The trends observed indicate that this is possible even at lower temperatures, if the residence time is increased further. Unexpectedly, the hydrogen concentration (i.e. the H2/TG ratio) was of minor importance, which can be a sign of either H2-saturation of the catalyst or a phase-split of the reaction mixture with resulting mass transport limitations for the hydrogen. Unfortunately, the catalyst showed strong signs of deactivation very early in the experiments, possibly due to impurities in the feedstock and/or to coke formation.

Many food products contain a network of fat crystals. The size and shape of these triglyceride crystals is extremely important in producing the good physical properties and texture for a high-quality final product. Control of crystal habit can affect a fat’s structure and hence the resultant behaviour. In this work the effects of phospholipids on the crystal habit of triglyceride crystals have been investigated. Optical and scanning electron microscopy, DSC and X-ray diffraction have been used. The effects of certain phospholipids on the crystallisation of fats have been shown, and large changes to crystal habit have been demonstrated. These changes are caused by the interactions of the phospholipid molecules with the crystallising triglyceride molecules. Interference with the crystallising molecules causes changes to the shape and size (habit) of the resultant fat crystals. Effects on nucleation and crystal growth are demonstrated. These dramatic changes to the crystal habit can have a significant effect on the properties of the resultant fat system. For example the process of fat fractionation could be significantly enhanced. Alternatively, the network structure of fatty products could be controlled or altered opening up the possibility of the development of new and improved products