As fat melts in the oven it assists in producing steam to bring about the layers iconic of croissants and Danish.
In addition to SFC and melting curves, a fat’s crystalline structure has an impact on its functionality.
“Fats crystallize in α, β or β’ forms, and this has a direct influence on the performance of fats in baked goods,” Dr. Ankolekar said.
The types of crystals present in a fat are determined by the fat’s composition, how it was plasticized, tempering, additives such as emulsifiers, and the storage environment. The type of crystalline structure contributes to texture, flakiness and creaming.
In cakes, for example, fat crystals of the fine β’ forms are smooth with lower melting range and an extended plastic range. These characteristics produce high-volume fine-textured cakes.
“β’ forms are small and needle-shaped and can entrap large amounts of liquid oil and are often the desired form but need the right processing,” Dr. Ankolekar explained. “Margarines and shortenings require fat to crystallize in the unstable β’ structure for smooth texture.”
Crystalline structure is a critical consideration for flat icings as well.
“Bakers need to consider if they need the flat icing to recrystallize, so it can firm up before being packaged,” Ms. Eagan said.
Flat icings often atop individually wrapped items must have quality icing that stays in place and firms up for downstream processing and visual presentation.
Fat crystals that don’t work for one product may provide the perfect functionality for another. Intermediate size fat crystals are grainier than β’ crystals, making them ill-suited for cake and icing formulations and even products that need laminating. However, pie crusts demand flakiness, which uniform fat distribution cannot deliver. Grainy crystalline structures work well in this application, preventing uniform fat distribution and keeping things flaky.
