title: Potato protein isolates: recovery and characterization of their properties.
abstract: An imitation of industrial potato fruit juice (PFJ) was prepared, using Canadian variety of potatoes, and was characterized of being composed of 22.9% patatin, 53.3% protease inhibitors, and 23.7% high MW proteins. To isolate potato proteins from PFJ, several extraction techniques were explored including thermal/acidic combination, acidic, FeCl3, MnCl2, ethanol and (NH4)2SO4 precipitations, and carboxymethyl cellulose complexation. (NH4)2SO4 precipitation led to the highest yield (98.6%) and to the recovery of protein isolates enriched in patatin with high resolubility. FeCl3 precipitation resulted in the highest purification factor (6.2) and isolates with the lowest relative proportion of high MW proteins (<4.6%); however, its optimal isolate showed a wide minimum solubility pH range of 3.0-6.0. FeCl3 and MnCl2 were identified as the best precipitating agents for the enrichment of isolates with >15kDa protease inhibitors. Trypsin inhibiting activities of protease inhibitors were highly preserved upon protein isolation than the chymotrypsin ones. Acidic-based protein isolate showed the highest specific lipid acyl hydrolase activity of patatin towards o-nitrophenyl butyrate, whereas FeCl3-based one exhibited the highest activity towards 4-nitrophenyl laurate.
authors.affiliation: Department of Food Science and Agricultural Chemistry, McGill University, 21, 111 Lakeshore, Ste-Anne de Bellevue, Quebec H9X 3V9, Canada.
authors.forename: Amanda
authors.initials: A
authors.lastname: Waglay
authors.forename: Salwa
authors.initials: S
authors.lastname: Karboune
authors.forename: Inteaz
authors.initials: I
authors.lastname: Alli
mesh_terms: D011232:Chemical Precipitation; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D010940:Plant Proteins / Q000737:chemistry* / Q000302:isolation & purification*; D011480:Protease Inhibitors / Q000737:chemistry / Q000302:isolation & purification; D055550:Protein Stability; D011198:Solanum tuberosum / Q000737:chemistry*; D012995:Solubility
chemical_list: D010940:Plant Proteins; D011480:Protease Inhibitors
keywords: Lipid acyl hydrolase; Patatin; Potato fruit juice; Precipitation; Protease inhibitors; Protein