Kinetic Modeling of Pectin Extraction from Wasted Citrus Lemon L

The aim of this study was to apply a kinetic model describing the simultaneous processes of pectin extraction and degradation from citrus lemon peels in order to valorize this abundant waste. To avoid many required experiments to this study, we developed a mathematical model using response surface methodology (RSM) with a small number trials (N = 23). The yield values of extracted pectin predicted by RSM model at different temperatures (40, 60, 80 and 94 °C), pH (1.50, 1.80, 2.50 and 3.00) for a time varying from 20 to 60 min were used to determine k ext (rate constant of pectin extraction) and k deg (rate constant of pectin degradation) of the kinetic model. At optimal pH (≈1.80), k ext was established to be varied from 3.184 × 10 −2 to 5.384 × 10 −2 min −1 and k deg from 2.152 × 10 −2 to 0.463 × 10 −2 min −1 . The activation energy at optimal pH was estimated at 9.41 kJ/mol. This kinetic model described adequately the pectin extraction process from citrus lemon peels and gave yield values that are in good agreement with the experimental results used to develop the RSM model. Graphical Abstract