Optimized extraction of pectin from cassava root cortex: evaluating aqueous and acidic methods

Cassava root cortex (CRC), which represents 10–12% of the weight of the cassava root, is a residue rich in pectin, a heteropolysaccharide with potential for food and pharmaceutical applications. This study aimed to develop optimal conditions for pectin extraction from CRC using hydrochloric acid and water, aiming to observe the behavior and characteristics acquired in each extraction. For this purpose, a central composite rotational design (CCRD) was used to observe the action of dependent variables (solvent: CRC flour proportion, temperature, and time) on the dependent variables (yield, degree of esterification, and galacturonic acid content). CRC flour presented significant levels of phenolic compounds (2088.78 mg GAE/100 g), anthocyanins (71.86 mg/100 g), and flavonoids (49.99 mg/100 g), besides low water content (4.91%). Aqueous and acidic extraction assays showed that acidic extraction resulted in higher yields (71.83%), with pectins of low (< 50%) and high (> 50%) methoxylation. Furthermore, it was observed that the interaction of time and temperature variables had greater weight in the regression coefficients, presenting significant effects in all treatments. Therefore, our results highlighted the best conditions for aqueous extraction (70 °C, 60 min, and proportion of 1:40) and acidic extraction (70 °C, 60 min, and proportion of 1:20), showing that the optimized pectin from CRC has good potential for use in various industrial applications.