Beyond electroporation: Solvent chemistry governs the success of pulsed electric field-assisted extraction of phenolics and anthocyanins from grape pomace.

Grape pomace is a phenolic-rich by-product whose valorization is frequently constrained by mass-transfer limitations during conventional extraction. Although pulsed electric field (PEF) pretreatment is widely recognized as an effective strategy for intensifying the extraction of bioactive compounds from plant matrices, it remains unclear whether the extraction gains promoted by electroporation are an intrinsic consequence of tissue permeabilization or are fundamentally conditioned by the extraction medium. Here, this question was addressed by investigating the interaction between PEF pretreatment and chemically distinct solvent systems during the sequential recovery of phenolics and anthocyanins from grape pomace. Three extraction cycles (40 °C) were performed using hydroethanolic, HCl-acidified, and citric acid-acidified aqueous and hydroethanolic media. Only the HCl- and citric acid-based aqueous systems responded positively to PEF pretreatment, with the aqueous citric acid system exhibiting the most pronounced enhancement, increasing total phenolic content by approximately 70% and total anthocyanin content by approximately 105% compared with the corresponding untreated control. PEF pretreatment also promoted a marked redistribution of compound recovery toward the first extraction cycle, increasing the extraction of anthocyanins, phenolic acids, and selected flavonoids while preserving solvent-specific extraction selectivity. Spectroscopic analysis revealed enhanced color intensity and pronounced hyperchromic effects without bathochromic shifts, indicating improved pigment recovery rather than changes in anthocyanin chromophore structure. Collectively, these findings demonstrate that the extraction response to PEF pretreatment is solvent-dependent. Rather than acting as an isolated intensification technology, PEF enhances matrix accessibility, whereas the extraction medium determines how effectively this increased accessibility is translated into phenolic and anthocyanin recovery. These findings provide new insights into the design of integrated PEF-assisted biorefinery strategies for plant by-products.