(194e) Protein Recovery from Potato Processing Wastewater: Pre-Treatment and Fouling Minimization

Waste treatment has been a challenge for the potato processing industry for many years.  The wastewater effluent with high concentrations of potassium and Chemical Oxygen Demand (COD) caused by the presence of starch, proteins, amino acids and sugars, imposes expensive treatment processes for the companies. However, this waste effluent contains high amounts of valuable by-products. Starch content of this waste stream that range from 15 to 20%, is being recovered using simple separation systems such as hydro-cyclones in some manufacturing sites but the commercially valuable protein ranging from 1-1.5 g/L is still being discharged into the waste stream. Potato proteins have high functionality and nutritional value and are considered as one of the best plant proteins and can be utilized in food applications if recovered in native form with high quality and be isolated by the methods that do not result in denaturation. Different techniques such as traditional concentration, heat coagulation and precipitation, ion-exchange using Expanded Bed Adsorption (EBA) and UF have been used to recover the potato fruit juice (PFJ) protein (potato fruit juice is the juice generated from potato starch production that mainly contains water, salts and protein). The methods all resulted in relatively high yield of recovered protein, but they either have failed to recover completely un-denatured high quality protein due to the usage of heat and acids or are complex and expensive to be used commercially. Ultrafiltraion membrane (UF) has been reported as an appropriate technology to recover relatively high yield of high quality potato protein. However, the optimization of membrane process to mitigate fouling problems, enhance removal of toxins and impurities such as microfiber and glycoalkaloids and achieve high quality protein products has not been systematically examined. In this study, fouling and protein recovery from potato process water was investigated utilizing a number of potential pre-treatments and filtration conditions to target high quality protein production. Sedimentation, centrifugation, prefiltration with paper filter and microfiltration were assessed as pre-treatments to remove particulate and fibrous matter prior to a final concentration with 10 kDa molecular weight cutoff ultrafiltration with the aim of removing low molecular weight components.