The solid gain of the samples will be measured based on the method of Antonio et al. (2008). The solid gain will be defined as the net uptake of solids by the purple sweet potato samples based on the initial weight. The obtaining data will be calculated for solid gain using the following equation.
SG=((w_f (1-X_f/100)-w_i (1-X_i/100)))/w_f
Where Wi and Wf are the initial and final (time t) sample weights, respectively, (g); Xi and Xf are the initial and final (time t) sample moisture contents, respectively.