The effect of different formulations and baking conditions on the physicochemical properties of gluten-free cakes

Response Surface Methodology (RSM) with Central Composite Design (CCD) was performed in this study to optimize the gluten-free cake formulation. The range of the independent variables, namely sprouted mung bean flour (5, 10, and 15% replacement of corn flour), Plantago mucilage (0.1, 0.5, and 0.9% replacement of egg), grape syrup (20, 40, and 60% replacement of glucose), and DATEM emulsifier (0.4, 0.8, and 1.2 %) were identified which affect the moisture, specific volume, firmness, porosity, and antioxidant activity of the gluten-free cake. Models were developed from the data to predict response variables from the factors evaluated. Models for all dependent variables were found to be significant. Significant models were then used to optimize selected response variables, highest moisture content, specific volume, and antioxidant activity with acceptable texture in the range of values measured in the control cake. Optimum conditions were 13.3% sprouted mung bean flour, 0.615% Plantago mucilage, 1.2% DATEM emulsifier, and 60% grape syrup. The optimized cake exhibited a moisture content of 31.2%, a specific volume of 1.87 cm³/g, a porosity of 19.2%, an antioxidant activity (DPPH) of 10.8%, and a hardness coefficient of 3.76 N. The influence of different baking methods on optimized formulation was evaluated. Cakes baked using a combination of microwave-infrared (MW30-IR70) heating showed significantly higher porosity (18.9%) and moisture content (∼31%) compared to cakes baked using only microwave (MW-40, MW-50) or infrared (IR) baking methods (p < 0.05). The samples with the highest antioxidant activity were those baked in a conventional oven (CO) (10.8%) and MW-40 (10.17%). Conversely, samples baked in a higher power microwave (MW-50) were found to have greater hardness (4.5 N) compared to those baked in a conventional oven (CO) (3.7 N). The sample with the highest overall acceptance score (4.20) from the evaluators' perspective was the one prepared using the conventional oven (CO) method, which did not have a statistically significant difference from the sample prepared using MW30-IR70 (p>0.05). However, the infrared oven improved gelatinization with a more desirable microstructure. Consequently, baking new gluten-free cake formulation in the microwave-infrared oven can be an innovative alternative.