Enhanced Protective Potential of a Pea Protein‐Fortified Fermented Almond Beverage Against Paraquat‐Induced Oxidative Stress

Oxidative stress, arising from an imbalance between reactive oxygen species and antioxidant defenses, drives numerous diseases. Paraquat (PQ) induces oxidative damage through free radical generation. Developing antioxidant-rich products from natural sources may mitigate these effects. We evaluated the antioxidant content and protective effects of a plant-based fermented beverage (PBFB) based on almond milk and plant protein. Methanolic extracts were analyzed for total phenolic (TPC) and flavonoid (TFC) content, as well as DPPH and ABTS assays. Fermentation enhanced antioxidant properties, increasing phenolic content (80.20 ± 0.81 vs. 119.60 ± 1.43 mg GAE/mg), total flavonoid content (9.32 ± 1.32 vs. 22.35 ± 1.52 mg CAE/mg), DPPH (4.97 ± 0.17% vs. 10.43 ± 0.15%), and ABTS (23.57 ± 1.46% vs. 44.30 ± 0.51%) radical scavenging capacity (p < 0.05). In vitro, PQ increased catalase (CAT) (16.36 ± 3.33 vs. 36.70 ± 5.52 units/min/mg, p < 0.05) and decreased glutathione S-transferase (GST) activities (39.42 ± 2.92 vs. 18.27 ± 2.37 µmol/min/mL, p < 0.05) in CHO-K1 cells. PBFB treatment partially restored GST activity (26.04 ± 2.30 µmol/min/mL, p < 0.05) and normalized CAT levels (21.25 ± 2.95 units/min/mg, p < 0.05). Cell viability remained unchanged. These findings highlight the synergistic effect of fermentation and plant protein enrichment, yielding a functional food with cytoprotective potential.