Recovery of Native Potato Protein Comparing Expanded Bed Adsorption and Ultrafiltration

Obtaining native protein from potato fruit water (PFW) acceptable for food consumption was attempted by comparing expanded bed adsorption (EBA) and ultrafiltration (UF).The methods were assessed on their process performance and the product quality. Extractable tuber proteins were recovered from lab-prepared PFW either by adsorption to an EBA column using a mixed mode resin (0.31 L) or by batch concentration in an UF (10 kDa MWCO, 0.093 m(2)) unit and then freeze dried. The yields on protein and esterase activity were higher (p < 0.05 and p < 0.01; Mann-Whitney U-test) in UF (3.2 g l(-1) PFW and 3.17 kU l(-1) PFW) than in EBA (1.8 and 1.21). The performance difference was also reflected in process productivity for esterase activity which was fivefold better (p < 0.01) in UF (4.30 kU h(-1)) than with EBA (0.84) due to the higher enzyme retention; protein productivities were the same. The content of solanidine glycoalkaloids was depleted to moderate levels but came out unaffected by the processing method: EBA 286 ppm, UF 213 ppm. The low levels of chlorogenic acid in all EBA preparations were negatively correlated to high brightness score (L* = 73.8%), a favorable attribute in food-quality proteins. Both methodologies produced native preparations of comparable protein content (75%). EBA processing, however, increased the fraction of the patatin protein which may offer advantages in food applications.