Influence of Cassia grandis galactomannan on the properties of sponge cakes: a substitute for fat.

Here we have proposed to evaluate potential replacers of fat in sponge cake formulations. Our investigation consisted initially of monitoring the physical-chemical changes in sponge cake batters caused by gradually replacing the vegetable fat/margarine of a control sample (standard sponge cake recipe) with galactomannan extracted from the seeds of Cassia grandis. Several samples were prepared where a 100% concentration of vegetable fat was substituted with galactomannan in different concentrations. We then compared both microscopic and macroscopic characteristics of pure fat cake batter formulations and formulations with controlled fat/galactomannan mixtures. At this first stage, rheometry and optical microscopy were employed to characterize the rheological features and air bubble distribution in the batters. In the second stage, the effects of fat substitution with galactomannan, now for the final baked cakes, were also monitored. Scanning electron microscopy (SEM) and standard sensorial tests were performed in order to correlate the final color, texture, and taste characteristics of the final sponge cake and those characteristics obtained initially for the batter. According to the statistical analysis of the data, a 75% fat replacement with galactomannan at only 1.0% concentration was achieved, while successfully maintaining surface microstructure, sensory acceptance, and rheological behavior similar to the original formulation containing only fat. Regarding vegetable fat substitution with galactomannan, our results allow us to conclude that rheometry and bubble distribution tests on the initial batters are useful indicators of the final cake quality.