Relation between hydration level and quality of steamed oat cakes: from the view of batter rheological properties

The effects of hydration level on the rheological properties of oat batters and quality of steamed oat cakes were evaluated. With the increase in hydration level, the apparent viscosity was sharply decreased from 18.47 to 7.08 Pa.s, and the frequency sweep results suggested an increasing fraction of uncross-linked component in oat batter. The water fluidity was enhanced, and the cross-linking of proteins were weakened, resulting in loose batter structure. Apparent viscosity and microstructure analysis suggested that the gas chamber size was negatively correlated with the viscosity. Large gas chamber formed by low viscosity batter was unstable, resulting in steamed oat cakes collapsed. Besides, a highly viscous batter resulted in excessive cross-linking and restricted gas expansion. Medium viscosity of oat batter, 15.28 Pa.s, with 110% water addition resulted in highest specific volume, cell area fraction and minimum hardness, 2.22 mL g(-1), 34.73% and 7.61 N, respectively.