Control fat bloom in chocolate.

Fat bloom is that thin gray layer of fat crystals that can cover the surface of chocolate. But now scientists at Switzerland's Buhler-Bindler have developed a seed crystallization process--called the SeedMaster System--that keeps chocolate products free from fat bloom longer.

In the process, you create a cocoa butter crystal suspension system. The liquid cocoa butter is partially crystallized in a shear crystallizer. The microscopically small crystals undergo additional processing in a conversion tank in which they are converted to their most stable form.

Next, it is necessary to cool the chocolate mass that is to be precrystallized, but this must be done without causing crystallization to occur. To do this, researchers developed a system in which they use static or dynamic heat exchangers. These units make it possible to cool the chocolate at elevated water temperatures.

Then the cocoa butter crystals are added at a controlled rate to the chocolate mass that has been cooled. The crystals and chocolate are uniformly mixed in a dosing and mixing unit. A static mixer performs a gentle mixing. It is not required to preform the crystals throughout the product. All that is necessary is to precool the individual ingredients while additional crystallization occurs within a short time after the seed crystal suspension is added. You might do this as part of a continuous mixing and forming process.

As the chocolate mass is seeded directly with stable cocoa butter crystals, the processing temperature could be up to 4 C greater than that for conventional masses that are precrystallized in tempering equipment. Because of the greater temperature, high-viscosity masses are easier to process because the heat reduces the viscosity. It's also possible to reduce fat levels in low-viscosity masses.

Seed recrystallization better resists fluctuations in temperatures due to the presence of crystals that have a maximum melting temperature. This leads to a more uniform precrystallization state. Seed precrystallization is especially helpful in chocolate-like masses whose continuous fat phase contains such fats and oils as hazelnut oil or almond oil and hardened vegetable fats. The stable cocoa butter crystals have several crystallization nuclei that make for fast recrystallization of the remaining fat. The high number of crystal nuclei creates a dense fine crystalline structure that retards fat migration.

Further information. Buhler-Bindler, CH-9240 Uzwil, Switzerland; phone: +41 71 955 31 36; fax: +41 71 955 35 82; URL: www.buhlergroup.com.