2.7. Water Holding Capacity (WHC) of SPI Gels Containing WG-Treated Okara

The sample mixtures were prepared as described in Section 2.5. Briefly, SPI was mixed with a WG-treated okara slurry and 0.25% MgCl₂ and 1% NaCl were added. Water content (W) and water holding capacity (WHC) were measured using a modification of a previously reported method [32]. An aluminum cup was weighed (m₀) and the sample mixture was added and then weighed again (m₁). The cup was heated using a drying oven at 105 °C overnight, cooled to 25 °C in a desiccator, and then weighed (m₂). The W was calculated using Equation (1):

A 1.5 mL microtube was weighed (m₃) and sample mixtures were added and then weighed (m₄). The gel was formed by heating at 80 °C for 30 min and the tube was centrifuged at 1000× g for 10 min. After centrifugation, the upper phase was weighed (m₅). WHC was calculated using the following Equation (2):

The data represent the average of three measurements for each sample.