Pulsed electric field-assisted aqueous fractionation of potato peel by-products into multifunctional food ingredients: Phenolics, protein-rich starch and dietary fibers

Abstract

The development of multifunctional, clean-label food ingredients from agro-industrial residues is essential to support circular economy principles and next-generation food systems. In this study, a novel aqueous fractionation process assisted by pulsed electric field (PEF) pretreatment was proposed to recover multiple functional ingredients from potato peel by-products (PPB). PEF was applied at 1, 3, and 5 kV/cm (500 pulses, 50 μs, 1 kHz), followed by sequential extractions using water at pH 7. This approach yielded three distinct fractions: (i) an aqueous extract rich in phenolic compounds and soluble proteins, (ii) a starch-based fraction with residual proteins, and (iii) a dietary fiber-rich flour (DFF). PEF significantly influenced phenolic recovery, with 3 kV/cm achieving the highest total phenolic content (TPC), while antioxidant activity (FRAP) remained unchanged. HPLC analysis revealed electric field-dependent variations in individual phenolics (ferulic acid, protocatechuic acid, 4-hydroxybenzoic acid, vanillic acid, trans-cinnamic acid, and kaempferol-3-O-rutinoside), suggesting possible conversion or degradation pathways. Although starch yield and composition were not affected, PEF altered granular morphology, reduced particle size, and modulated techno-functional properties, including pasting behavior and water adsorption capacity. Moderate intensity (3 kV/cm) increased peak viscosity, whereas 5 kV/cm enhanced hygroscopicity, indicating structural reorganization. Proteins maintained their molecular integrity across all fractions, although solubility decreased at higher intensities. Overall, PEF-assisted fractionation enables the generation of sustainable hydrocolloid-rich ingredients with tailored techno-functional properties for food formulation.