Water relations in high ratio white cake batter (AACC 10-90) and reduced calorie microcrystalline cellulose (MCC) substituted cake batters were investigated using differential scanning calorimetry (DSC). The amount of freezable water at -50(DEGREES)C, defined as free water, was subtracted from the total water in the sample to calculate bound water present in the batters. The water binding capacity (WBC) was determined as the moisture content (g total water/g solids) at which there was no freezable water present in the sample. This value was calculated from a linear regression equation in which the amount of freezable water was expressed as a function of moisture content. The WBCs of the high ratio white cake batter and the 70% substituted batter were 0.335 g total water/g solids and 0.299 g total water/g solids, respectively. The slopes (g free water/g total) of the two lines were significantly different. The substituted batter had a slope of 0.98 and the control of 0.89. These values indicated that the control had a greater ability to bind water above the WBC. As water was added to the control batter above the WBC, 11% of the water became bound. Eighty-nine percent was added as free water. Almost all of the water added above the WBC in the substituted batter was added as free water. If all of this water had been added as free water, the slope would have been one;The WBCs of sucrose and MCC were determined as 0.416 g total water/g solids, and 0.270 g total water/g solids, respectively. These differences verify that the WBCs for the cake batters were due to the surcrose removal and substitution by MCC;The WBC of cake batters at a constant level of added water and five levels of MCC substitution showed that as MCC increased, the bound water as a percent of total water decreased significantly;The heat of vaporization peak areas for the control and the 70% substituted batter were measured using DSC. MCC level did not affect the peak area units/g total water in the cake batters;Brabender Visco/amylograph measures for the temperatures for initial increase in viscosity of the control batter, the substituted cake batters (six levels of MCC), flour-sucrose-water slurries, and flour-sucrose-MCC-water slurries were made. The temperatures were grouped over a narrow range from 79 to 81(DEGREES)C for all batters. As sucrose decreased, the temperature for initial viscosity increase decreased in slurries and batters. There was no effect on temperature due to increased MCC substitution;Physical incorporation of MCC into the cake batters was investigated using phase contrast light microscopic techniques. MCC particles were observed suspended in the aqueous phase of the batter.