Physicochemical properties of hydrolysate and residues from HCl-hydrolyzed potato pulp

Potato pulp, a by-product of potato starch processing, is rich in carbohydrates like starch, pectin, and cellulose that form a complex matrix. The underutilization of potato pulp leads to environmental pollution and economic costs. In this study, potato pulp was treated with 2 N hydrochloric acid (HCl) at 50 °C for varying durations, and the physicochemical properties of the resulting hydrolysates and insoluble residues were examined. While insoluble residues could not be further hydrolyzed after 24 h, the depolymerization of the soluble hydrolysate remained active, with oligomers of degree of polymerization 3–6 rapidly converting into glucose and maltose. Solubilization mainly involved starch and pectin, leaving a largely intact cellulose matrix. As a result, the insoluble residue exhibited decreased gelatinization enthalpy and reduced pasting viscosity. These findings highlight the potential for processing potato pulp into sustainable materials, enhancing its utilization and reducing environmental impact.