Optimization of Extraction of Pectin from Valencia “Midknight” Orange Peels with Citric Acid Solution

Abstract

The extraction of pectin from Valencia “Midknight” orange peels with a citric acid solution is experimentally studied, and these data are used to model and then optimize the process. The experimental data reported are the pectinesterase activity as a function of blanching time, the moisture of orange peel as a function of drying time, and the amount of pectin extracted as a function of extraction time at different ratios of citric acid solution to orange peel. These data permit finding the equilibrium and kinetics parameters of the extraction model, such as the diffusivity of pectin through the peel D = 3.0375 × 10−11 m2 s−1. Then, the model is used to optimize the extraction variables: the optimal extent of extraction is located on an upper bound imposed on the extraction time, which must not exceed 1 h due to product quality considerations and the optimal ratio of solution to solids is R = 15.