Investigation of dielectric properties, total phenolic content and optimum formulation of microwave baked gluten-free cakes.

This study discusses the production of microwave baked gluten-free cakes formulated by mixing buckwheat flour and rice flour at different concentrations. Three different ratios of buckwheat flour to rice flour (20:80%, 30:70%, 40:60%) and two different gum types (xanthan and guar gum) with a white layer cake recipe were employed. The batters were baked in microwave oven at different microwave powers (540 W, 450 W, 360 W) for different baking times (3 min, 3.5 min, 4 min). The effect of microwave power, baking time and buckwheat flour concentration on weight loss, color, specific volume, porosity, total phenolic content and dielectric properties were investigated. The optimum microwave power, baking time and buckwheat flour concentration were found as 432.77 W, 3 min, 40% for guar gum added cakes and 360 W, 3.70 min and 29.23% for xanthan gum added ones. It was found that weight loss and color values of the cakes that were baked at the optimal conditions were less than those of control cakes. On the other hand, total phenolic content, specific volume, porosity, dielectric constant and dielectric loss factor values were higher for guar gum added cakes compared to control samples. In addition, it was observed that the cakes prepared with guar gum had similar pore size distribution with control cakes. As a conclusion of the study, it can be declared that surface color and specific volume problems of microwave baking could be solved by addition of guar gum to the formulation which also enables the production of functional, phenolic rich microwave baked cakes.