Characterization Of Proteins Recovered From Potato Processing Waste Effluents

Potato industry has developed rapidly in recent years in China, industrialization bases have formed in so many places. At present, the amount of potato processing waste effluents is more than 8 000 000 t (COD content up to 10000mg/l)。As the high processing cost,the limit of frozen weather and technology, most of the process wastewater was discharged into rivers and reservoirs directly, which caused serious pollution and waste. With more and more strict of the policy on energy concervation and pollution reduction, it was time to deal with the wastewater economically and effectively.In this paper, recovery of potato protein is primary goal, the same time, to bring down the COD content economically and effectively.First, simulate the existing evaporation and concentration technology, by single-factor experiment and orthogonal experiment, The optimum conditions obtained were time 2.5h,pH5.2, the crude protein yield and recovery percent of protein is 7.00 mg/mL and 43.95%, respectively, ratio of COD elimination is 42.14%,however,the practical factory conditions is time 0.5h,pH4.8. Besides, also study on effect of apparent morphology of protein obtained by different drying methods, supply raw materials to the latter experiment also.Secondly, study on the use of ultrafiltration technology in the recovery of potato proteins from potato processing waste effluents, the effect by operating pressure, temperature and pH value and the cleaning of ultrafiltration membrane. Based on an overall consideration of various factors, The optimum conditions as follow: pH 5.8,temperature 22℃, pressure 0.10Mpa, the rejection of protein is 80.46%. The best cleaning agent is 0.05% of the alkaline protease (pH 9.0), the pure water flux recovery coefficient reached 99.94% by alkaline protease anti-washing. The ratio of COD elimination is 57.99%.At last, multi analyze Chemical characterization and functional properties of two potato proteins sample, refer to salting-out potato protein as reference materials, study on protein denaturation, apparent morphology and content of amino acids, the results as follow: the salting-out potato protein and ultrafiltration potato protein are superior to acid-evaporation potato protein, the level of protein denaturation and level of apparent morphology: salting-out potato protein>ultrafiltration potato protein>acid-evaporation potato protein.