Viscosity and methods of its determination, we examined in detail in the chapter on emulsifiers. However, here it seems appropriate to once again raise some points about it is the production of chocolate.
With the development of technology of the automated molding of chocolate glaze and cooking it becomes even more important a strict control of flow (viscosity).
In addition, it has become necessary to save an expensive ingredient such as cocoa butter, using emulsifiers or mechanical methods to increase the viscosity of chocolate with a low content of cocoa butter. The fluidity or viscosity of chocolate can not be expressed by a single parameter, because due to the presence of many dry substances (sugar, cocoa beans), chocolate does not have the properties of a Newtonian liquid, and its actual viscosity depends on the speed of mixing or the shear rate.
The solids content can be further modified by adding cocoa butter particles that are inevitably present in the chopped chocolate, and since this factor varies depending on the method and degree of chopping of the chocolate, the true viscosity value during the manufacturing process is rather difficult to obtain. In practice, usually enough to obtain a certain viscosity of chocolate, a clear normalization of the procedure for chopping chocolate mass in a specific equipment. Dry conching technology and new shoe machines could increase the fluidity (reduce viscosity) of the chocolate mass. This was partly due to a general reduction in moisture content up to 1-1,5% (often up to 0,5%). Decrease in viscosity is also facilitated by more intensive mechanical processing of the material in the shoe casings.
Considering the problem of the viscosity of chocolate, it should be taken into account that the presence of free moisture in insignificant amounts significantly increases its viscosity, and therefore direct determination of the moisture content is not always effective. It is more convenient to inspect the equipment for condensate or leaks, and also to analyze the ingredients used. Sugar or cocoa liquor may contain lumps of a more moist material, but it is less likely to be supplied with bulk ingredients. Sometimes such an effect occurs during the storage because of poor-quality or damaged seams in the package. Processing of such raw materials can cause problems - especially in the presence of inverted sugars; In rare cases, in conditions of high humidity, moisture can be absorbed into the layer of chocolate mass on the grinding rolls.
We should also mention about the method of adding lecithin in chocolate. Lecithin (like some other emulsifiers) is a surface active agent, and in the process and should be kept on the surface of the particles Chocolate. It should be added to the end of the process (for example at the completion of conching) providing sufficient time to disperse.
However, data were obtained, that by using certain formulations effectively adding a quarter or third of the total weight of lecithin on a mixing step immediately before grinding. In this case, the moisture content of the mixture may be higher than in the final product and the required viscosity of the chocolate mass to feed it to the rolls can be obtained at a low content of cocoa butter. This technique results in significant savings.
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