Effect of water quality on degumming and stability of soybean oil

Solvent‐extracted crude soybean oil was degummed with deionized distilled water containing various amounts of CaCO 3 −MgCO 3 FeCl 2 , and NaCl. The total phosphorus content remaining in the degummed oil was determined and the peroxide value of the degummed oil held at 98–101 C was measured daily for 10 days. The results were compared statistically with those from oil degummed with deionized distilled water as a control. It was found that 250 mg/L of CaCO 3 −MgCO 3 significantly reduced the efficiency of the degumming process. FeCl 2 at concentrations of 150 and 250 μg/L and NaCl at 300 mg/L resulted in the removal of more phosphorus than the control at the 5% level of significance. Generally, the stability of the degummed oils decreased as the salt concentrations increased. The rate of oxidation was greater for oils degummed in the presence of FeCl 2 than of NaCl and CaCO 3 −MgCO 3 under the same conditions.