Abstract:

In this study, the wastewater from the alkaline refining of oil was centrifugated, followed by the supernatant was then added to gross soybean oil for the removal of hydrated phosphatides, followed by further enzymatic degumming for the removal of non-hydrated phosphatides in order to achieve the recycle utilization of the wastewater. Based on single-factor and orthogonal array experiments, the optimal conditions for the enzymatic degumming with the wastewater were determined to be: wastewater loading, 2.5%; phospholipase A1 loading, 30 mg/kg; reaction temperature, 55 ℃; reaction pH, 4.9; and stirring speed, 90 r/min. The soybean oil degummed under the optimal conditions showed a phosphorus content of 4.9 mg/kg. This demonstrates that the wastewater from the alkaline refining of oil can be used as an alternative to softened water for the degumming of gross oil, and 34－36 kJ calorie will be saved during the production of 1 kg of finished oil but the yield will be increased by above 0.2%.

Key words: gross soybean oil, wastewater, phospholipase A1, degumming, energy saving