Study On Protein Recovery Method And Process Design From Potato Starch Wastewater

China is a big potato planting country,and the total output of Potato in China has jumped to the first place in the world.With the rapid development of potato planting industry,the comprehensive utilization of potato processing has become a recent research focus.In this paper,potato is used as raw material,potato starch production process is simulated,the waste water is collected,the protein in potato starch wastewater is recovered by flocculation method,acid heat method and ultrafiltration method.The protein recovery rate of the three methods is compared,and the optimal recovery method is designed.The main conclusions are as follows:(1)Study on recovery of potato protein by acid-heat method: single factor test and orthogonal test were used to optimize the process conditions by adjusting the ratio of liquid to material,p H,settling time and temperature of acid-heat method and taking potato protein recovery as evaluation index.The results showed that the optimal recovery conditions were as follows: liquid-solid ratio 2.0m L/g,p H 4.0±0.2,settling time 25 min,settling temperature 30±2℃.Under these conditions,the recovery and purity of potato protein were 74.09% and70.27% respectively.(2)Study on recovery of potato protein by ultrafiltration: the wastewater from potato starch production was recycled by ultrafiltration equipment,and the process conditions were optimized by single factor test and orthogonal test by adjusting the pressure,temperature and p H,and taking potato protein recovery as the evaluation index.The results show that the optimal recovery conditions are as follows: operating pressure 0.05 MPa,temperature 25±2℃,p H 4.0±0.2.The recovery and purity of potato protein were 70.12% and 76.28% respectively.(3)Study on the process of potato protein recovery by flocculation: chitosan is added to starch wastewater,and protein is recovered by adding acid to adjust value,temperature control,centrifugation,neutralization,drying and other processes.Single factor test and Box-Behnken combined test were used to optimize the recovery of protein.The optimal recovery conditions were as follows: chitosan dosage 6mg/100 m L wastewater,p H4.0,temperature40.0 ℃,treatment time 40 min,protein recovery of potato starch wastewater 77.31%,purity 80.36%.(4)The production process of protein recovered from potato starch wastewater by flocculation method,the general layout of the plant and the layout of the production workshop with an annual output of 300 t potato starch wastewater were designed.The production equipment was selected according to the process requirements and material balance results,and the consumption of water,electricity and steam and labor force were calculated.Finally,the feasibility of protein recovery from potato wastewater was confirmed by technical and economic analysis.This process can provide technical support for the industrial production of potato wastewater protein and promote the development of potato protein industry.