Investigation on replacing egg with soy flour and Psyllium seed gum in gluten-free rice cake

The aim of this study was to investigate the effect of egg replacing with soy flour in different proportions (0, 25, 50, 75 and 100% w/w based on the weight of egg) and incorporation psyllium gum in different proportions (0, 0.5, and 1% w/w based on the weight of rice flour) on the physicochemical and sensory properties of rice cake. A factorial experiment with a completely randomized design with three replications was used for data analysis. The substitution of egg by soy flours up to 50% significantly improved the technological characteristics (color, texture and porosity) and sensory attributes of the samples (p<0.05). Increasing of the proportion of egg by soy flour by more than 50% significantly decreased these properties. The addition of up to 1% psyllium gum to the batter not only increased the batter viscosity, but also improved moisture, volume, porosity and softness of the cake samples. Compared with the sample containing the whole egg and without psyllium gum, the highest and the lowest contents of moisture, volume, porosity, softness, and sensory properties were determined in the samples containing up to 50% soy flour as an egg substitute and incorporated with 1% psyllium gum and the samples containing full soy flour and without psyllium gum, respectively. A higher darkness (L value) and redness (a value) and low sensory scores of tastes and color of compared to the control, were observed in the samples containing up to 50% soy flour as an egg substitute and incorporated with 1% psyllium gum. Therefore, it was found that the egg could be substituted by the soy flour in gluten free cakes and incorporation of psyllium gum to the cake batter formulation with reduced egg can be effective for improving their physicochemical and sensory characteristics.