Protein recovery from potato processing water: Pre-treatment and membrane fouling minimization

- Membrane was used to recover protein from potato processing water (PPW).
- A combination of pre-treatment including MF, reduced UF fouling severely.
- High yield of highly concentrated potato protein was achieved by this treatment.
- Cleaning of PES UF membrane was 97% efficient with 100 ppm NaOH solution.

Extracting desirable potato proteins from potato processing industry water that contained other major components such as starch and fibre was investigated using membrane processes. The method was assessed based on the recovery yield, concentrating the protein and minimising the fouling by different operating conditions and combination of pre-treatments.In this laboratory scale study, the recovery of protein from potato processing water (PPW) was evaluated by using seven combinations of sedimentation, centrifugation, paper filtration, microfiltration (MF) and ultrafiltration (UF) processes to achieve high yields of highly concentrated protein. The removal of 95% of starch and 78% of fibre were achieved by centrifugation at selected conditions and using 2.5 μm filter paper. The filtrate was treated with a 0.22 μm Polyvinylidene difluoride (PVDF) MF membrane prior to the UF process. The inclusion of the MF process led to the reduction of UF fouling by 30% assessed from the transmembrane pressure. UF membrane of 10 kDa Polyethersulfone (PES) was effective in concentration of protein, rich in protein from the patatin family. Little loss of the higher molecular weight proteins was observed with the combination of pre-treatments and ultrafiltration. Fouling minimization was approached through different pre-treatments, without chemical addition and pH change to prevent denaturation of protein. Fouling was improved by 72% using the proposed process compared to that of centrifugation as pre-treatment only prior to ultrafiltration. Three types of cleaning detergents including acid, base and surfactant were studied to investigate cleaning efficiency and the mechanism of fouling. Higher cleaning efficiency (97%) and sustainable cleaning were achieved with base cleaning (100 ppm Sodium hydroxide) compared to acid cleaning (100 ppm Hydrochloric acid) and surfactant cleaning (5 wt% Sodium dodecyl sulfate).