Role of ingredient interactions on structural and physycal characteristics of cake batter

Cake batter is a dispersion of macromolecular biopolymers. Starch and proteins play a key role in determining the structure, the rheology and other physical properties, as well as the sensory perception of the finished product. Furthermore, the texture of the cake depends on the formulation, the aeration of batter, the batter-crumb transition and its stability after baking. To control the quality of this finished product, it is essential to understand the effects of the ingredients on batter properties during mixing and baking. This work is devoted to investigate the effect of interactions of the ingredients on protein and starch features. Protein secondary structure and hydrophobicity were evaluated by Attenuated total reflectance-Fourier Transform Infrared (ATR-FTIR) and Fluorescence (FS) spectroscopies, respectively. Regarding starch, thermal and pasting properties were investigated by differential scanning calorimetry (DSC) and MicoViscoAmylograph (MVAG), respectively. The work was done on both model and real batter systems. ATR-FTIR spectra showed that fat addition greatly affected protein conformation, and specifically alpha-helix structures, rather than the other ingredients (e.g eggs, sugar, pregelatinized starch). This result shows the importance of the fat-proteins interactions that could result in a poor development of the protein network by increasing alpha-helix structures. FS results showed that the changes in protein hydophobicity, in the final model system (batter),was more related to egg and sugar addition rather than to the other ingredients such as the fat. These changes are related to the exposure of tryptophan to more hydrophobic environment by egg and sugar presence. During baking, interactions among ingredients affected the melting point of fat, the denaturation of proteins and batter-crumb transition that moves towards higher temperatures, as determined by DSC. Finally, during cooling, the formation of the starch and proteins gel measured by MVAG controlled the final viscosity reached during cooling which contributes to the texture of the material of the cell wall of the finished product. This confirms that starch and proteins play an important role in the final structure of the finished product. In conclusion, this work highlited the impact of fat on protein conformation in batter. While the competition between ingredients on water controlled phase transitions during cake batter baking which is fundamental to explain batter-crumb transition and consquently the finished product quality.