The Effect of Percentage and Particle Size of Date Seed Powder on the Qualitative Characteristics of Batter and Gluten-free Sponge Cake

Date seed, as a by-product of date processing industries, could be regarded as an excellent source of dietary fiber with interesting technological functionality. This study was conducted to investigate the effect of date seed powder (DSP) at different levels (0, 20, 30, and 40%) with different particle sizes (125, 250, and 500 mm) as a starch substitute on the physicochemical properties of batter and gluten-free sponge cake. According to the results of this study, the number of air bubbles in batter increased with decreasing particle size of DSP. By increasing the DSP level, batter consistency, firmness, viscosity index, and cohesiveness, as well as cake density were significantly increased; while the cake specific volume decreased. A significant increase in the cake volume index (at 40% level) and, the decreasing trend of batter consistency, firmness, viscosity index, and cohesiveness were observed by decreasing the DSP particle size. The results of colorimetry (L*a*b*) indicated that the addition of DSP and reducing its particle size significantly (p<0.05) reduced the color index of L * and * b, while increased the a* value of crumb color. The cake samples with higher levels of DSP were significantly harder and gummier (p<0.05). Moreover, with the addition of DSP, the porosity and crust color score of the cakes significantly reduced; and the DSP with larger particle size significantly (p<0.05) decreased the texture and flavor score of the cakes. Overall, the addition of up to 30% DSP with small particle size can be used in the production of gluten-free cakes with suitable sensory attributes.