Optimization of the acid extraction process of pectin from cassava cortex

Pectin is an additive generally extracted from citrous and apple peels, but an increasing demand has stimulated the search for new commercial sources of this product. The cassava cortex is rich in pectin and could be destined for reuse as a new source of this additive, since the disposal of cassava processing residues results in soil and water contamination. Thus, the aim of the present study was to extract pectin from cassava cortex. Initially the flour of this residue was obtained by convective drying and characterized, providing evidence for the possibility of extracting pectin. A central rotational composite design was used to define the best extraction condition based on yield, degree of exterification and galacturonic acid for two extracting solvents (citric and acetic acid) in response to the variables concentration, time and temperature. After extraction, the samples were submitted to convective drying to obtain pectin powders. The optimum condition for pectin extraction was obtained using the desirability function of the Statistica software with the degree of esterification as the priority variable, since the aim was to obtain quality pectin favorable for application. According to the results obtained, the optimized extraction conditions with citric acid were a concentration of 7%, temperature of 62 °C and time of 90 min. With acetic acid they were a concentration of 7%, temperature of 80 °C and process time of 90 min. Graphical abstract