The use of some dietary fibers in gluten-free cake formulations

The objective of this study was to determine the effects of using different amount of high dietary fiber powders that are prepared from different fruit and vegetable pomaces on batter rheology and quality characteristics of gluten-free cake. In the first part of the study, apple pomace powder (EPT), carrot pomace powder (HPT) and orange pomace powder (PPT) that have high dietary fiber content were obtained by drying and grinding of apple, carrot and orange pomaces. Moisture, pH and total dietary fiber analysis were performed on these powders. It was determined that APP, CPP and OPP have 64.84, 83.91 and 82.22% total dietary fiber content, respectively. In the second part of the study it was aimed that to improve the dietary fiber content of gluten-free cake with incorporate EPT, HPT and PPT replacing different amounts of rice flour (0, 5, 10, 15%) . Flow behaviour and viscoelastic behaviour of dietary fiber enriched cake batters were investigated. According to rheological studies, Power Law and Casson model were suitable to represent the rheological characteristics of cake batters. For Power Law model, consistency indexes of cake batters were between 46.54-226.50 and flow behaviour indexes were bettween 0.36-0.49. It was observed that apperent viscosity, elastic modulus (G') and viscos modulus (G'') of batter increased with increasing dietary fiber powder content. Furthermore, specific gravities of cake batters were determined and it was observed that addition of dietary fiber powder increased specific gravity, except 5% EPT and 5% PPT. In the last part of the study volume, symmetry and uniformity indexes, specific volume, porosity, colour and texture profile analyses; moisture, ash, crude lipid and crude protein analyses; sensory analys were performed in order to determine the quality characteristics and nutritional properties of baked cakes and consumer preferences, respectively. Fiber enriched gluten-free cake samples resulted in decreasing volume index and increasing hardness values when compared to the control sample. Nevertheless it was determined that cakes which prepared with 5% PPT have equivalent volume index, specific volume, porosity and hardness values to control cake sample. Sensory properties of cake samples were investigated in terms of colour, texture, appearance, flavor and overall acceptablity and cakes with 5% PPT had greatest acceptance by panelists. Key words: Gluten-free cake, dietary fiber, apple, carrot and orange pomace powder, batter rheology