For recovering potato protein from potato processing wastewater, the effects of temperature, pH, volumetric airflow rate, liquid loading volume and sparging time on the foam separation performances were investigated using the column with the spiral internal component (SIC). A two-stage foam separation technology was designed to improve both the enrichment ratio and recovery percentage of potato protein. The results showed that the SIC and specially the increase of temperature were effective for improving the enrichment ratio of potato protein. A best enrichment ratio of potato protein of 4.69 was obtained under the optimal conditions of temperature 45 degrees C. pH 7, volumetric airflow rate 100 mL/min, liquid loading volume 300 mL and sparging time 90 min. The total recovery percentage of potato protein was as high as 73.4% by using the two-stage foam separation technology. So the two-stage technology was effective for the protein recovery from potato processing wastewater. (C) 2012 Elsevier Ltd. All rights reserved.