Synergistic effect of combined sucrose substitutes and partially gelatinized oat flour on gluten-free steamed oat cakes produced only by oat flour

The role of sucrose substitutes and partially gelatinized oat flour in oat-fermented food systems needs to be studied. Therefore, the synergistic effect of sucrose substitutes and partially gelatinized oat flour on the rheo-fermentation, water distribution, and textural properties of steamed oat cakes was explored. The results showed that compared to sucrose, raffinose was more easily used by yeast, leading to the highest total gas volume. Raffinose had much stronger competitive hydration ability than xylitol and maltitol, causing reduced viscoelasticity of the batter and incomplete gelatinization of the starch. Compared to raw oat flour, roasted oat flour with 30% and 50% gelatinization degrees (G30 and G50) resulted in a collapsed structure of steamed oat cakes, ascribed to a dense packed structure formed by starch. The mixed oat flour (M30) that represents 50% raw oat flour and 50% G50 oat flour formed a more stable gas chamber structure. The steamed oat cakes made by the combination of raffinose and M30 flour showed the highest gas cell area fraction (37.75%), and moderate springiness (0.88). In conclusion, the combination of raffinose and mixed oat flour can improve the texture quality of fermented oat-based foods.