Description:
ABSTRACTA model based on the mathematics of diffusion was developed to predict the retention of vitamin C of potato strips blanched in water. The vitamin C loss mechanism is by diffusion in unsteady state, considering the losses caused by enzymatic action or thermal degradation to be negligible. The apparent diffusion coefficient of vitamin C in potato is supposed to be constant with the concentration, and variable with the temperature according to equation Da= Da0 exp (− Ea/Ra T), in which Da0 and Ea are experimental values different in the 25–65°C and 65–100°C temperature ranges. The model determines adimensional average temperatures and vitamin C average concentration as a function of blanching time, at 66, 77 and 88°C, in straight cut potato strips of 9.5 × 9.5 × 96, 11 × 11 × 96 and 13 × 13 × 96 mm, with heat transfer coefficients ∞, 1000 and 300 W/m20C, respectively. The model was verified using published data.