Pulsed electric field assisted oxalate reduction in spinach (Spinacia oleracea L.) leaves

Spinach (Spinacia oleracea L.) is a nutrient-dense leafy vegetable, yet its high soluble oxalate content restricts safe consumption. Pulsed electric field (PEF) technology was evaluated as a pre-treatment to reduce oxalates in two spinach varieties, Pusa Vilayati Palak (PVP) and Spinach All Green (SAG). Whole leaf stacks (20 g) were immersed in phosphate buffer and treated in a cylindrical chamber with parallel electrodes at 80 mm gap using 100 μs square pulses of 0.9-2.4 kV/cm, 5-12.48 Hz for 2 s, followed by soaking in isotonic solution (1:10 w/v) for 6 h. Oxalate reductions were 65.44% in PVP and 60.78% in SAG, compared to 39.26-42.15% with soaking alone. Viable electroporation was achieved with 12-25 pulses of 1.5-2.1 kV/cm for PVP and 17-25 pulses at 1.8-2.4 kV/cm for SAG. Electrolyte leakage, temperature, leaf firmness, phenolic content, and antioxidant activity remained unaffected, showing that PEF-assisted soaking is effective for producing safe, low-oxalate spinach.