Effect of fat substitution on the textural properties of cake

The effect of the level of fat substitution in cakes as well as the type of fat replacer on the textural behaviour of the product was investigated by instrumental and sensory analysis. Samples, which were varying in levels (35, 65 and 100%) and types (carbohydrate or protein based) of fat substitution were subjected to a compression test and the obtained stress strain, sigmoid curves were fitted to a mathematical model. All samples with fat substitutes presented steeper stress-strain curves compared to control, indicating greater firmness and lower crumbliness of the texture, which was also verified by the sensory analysis. According to the sensory evaluation the increase of substitution level results in increased firmness, and decreased crumbliness and mouth feel decomposition. There was generally an agreement between instrumental and sensory results except for resistance to deformation that appeared to be lower by instrumental analysis of samples containing higher than 65% fat substitute due to the presence of larger pores in their structure. The greatest differentiation of cake firmness among the different fat substitutes was observed at 100% substitution with the protein based fat substitute presenting the highest resistance to deformation and consequently the highest firmness, which was also verified by the sensory analysis. Samples with total fat replacement were evaluated as not acceptable by the sensory panel regardless of the type of the fat substitute.