Physicochemical and Functional Properties of Protein Extracted from Potato

The aim of this study is extraction of potato protein via incorporation of ultrafiltration with different diafiltration times (90, 285 and 480 min), and evaluation of physicochemical and functional properties of extracted protein. So, in terms of functional characteristics (solubility, water and oil absorption capacity, emulsifying activity and emulsion stability) the concentrated permeate and retentate proteins, have been compared with control sample. In retentate and control samples the solubility increases significantly (P˂0.5) with raising the pH from 3 to 7, inverse it decreased between the 7 to 9. In addition, it was found that the solubility of retentate proteins were significantly (P˂0.5) more than control and permeated proteins. Also, the water absorption capacity of retentate proteins (18.85 g Water/ g protein Retentate 480 min) were more than the other samples (2.54 g Water/ g protein Permeate 90 min). Whereas, oil absorption capacity was significantly (P˂0.5) depended on diafiltration time and process. In a way that, by increasing the time this parameter dropped in all of the samples. It was also found that, the oil absorption of retentate samples (59.09 g oil/ g protein Retentate 90 min) were significantly (P˂0.5) more than the permeate ones (32.13 g oil/ g protein Permeate 90 min). Emulsifying activity and solubility of retentate samples were significantly grew by addition of diafiltration time, while these indexes reduced in permeate samples. The thermal analysis of retentate sample (with 480 diafiltration time) indicated that, it had higher water absorption capacity than control.