Ultralow phosphorus achievement in vegetable oil degumming: Synergistic effects of citric acid chelation and trace NaOH flocculation

Degumming is critical for downstream refining efficiency and edible oil quality, but conventional water degumming is incomplete, while enzymatic degumming is slow. This study developed a green and energy-efficient hybrid degumming process, combining instantaneous citric acid chelation with trace sodium hydroxide (NaOH) flocculation. Plackett-Burman screening and Box-Behnken optimization determined the optimal conditions: 339 mg/kg citric acid, 167 mg/kg NaOH, 1.76 % water at 70 °C, which reduced residual phosphorus to 0.22 mg/kg (lower than acid degumming and enzymatic degumming). Confocal laser scanning microscopy (CLSM) showed that NaOH-induced charge neutralization promoted rapid phospholipid flocculation. This process reduced citric acid consumption to 10 % of that in acid degumming, used only 0.017 % NaOH, and shortened degumming time by 30 min compared to acid degumming and 2–4 h compared to enzymatic processes. It aligns with sustainable development goals by cutting chemicals, energy, and emissions.