title: Effects of protein separation conditions on the functional and thermal properties of canola protein isolates.
abstract: Canola meal protein isolates were prepared from defatted canola meal flour using alkaline solubilization and acid precipitation. A central composite design was used to model 2nd-order response surfaces for the protein yield and the functional properties of protein isolates. The solubilization pH and precipitation pH were used as design factors. The models showed that the protein yield and functional properties of isolates, such as water absorption and fat absorption, were sensitive to both solubilization pH and precipitation pH, whereas the emulsification was sensitive to only solubilization pH. Gel electrophoresis analysis of protein fractions gave evidence to the compositional changes between proteins isolated under different conditions. Differences in glass transition temperatures suggest that proteins tend to be more denatured when solubilized at highly alkaline conditions. These conformational and compositional changes due to different protein separation conditions have contributed to the changes in functional properties of protein isolates.
  
  
  CONCLUSIONS
  Protein isolation conditions may be determined primarily through optimization of total protein yield. Improvements in protein functional properties may be achieved with a relatively small sacrifice in yield by altering isolation conditions.
authors.affiliation: Department of Agricultural and Biosystems Engineering, North Dakota State University, Dept. 7620, P.O. Box 6050, Fargo, ND 58108-6050, USA.
authors.forename: Wajira A R
authors.initials: WA
authors.lastname: Manamperi
authors.forename: Dennis P
authors.initials: DP
authors.lastname: Wiesenborn
authors.forename: Sam K C
authors.initials: SK
authors.lastname: Chang
authors.forename: Scott W
authors.initials: SW
authors.lastname: Pryor
mesh_terms: D029741:Brassica rapa / Q000737:chemistry*; D011232:Chemical Precipitation; D004044:Dietary Proteins / Q000032:analysis* / Q000191:economics / Q000302:isolation & purification*; D045703:Emulsifying Agents / Q000737:chemistry / Q000191:economics / Q000302:isolation & purification; D005229:Fatty Acids, Monounsaturated / Q000032:analysis; D005525:Food-Processing Industry / Q000191:economics; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D007220:Industrial Waste / Q000032:analysis / Q000191:economics; D007700:Kinetics; D008956:Models, Chemical; D008970:Molecular Weight; D010940:Plant Proteins / Q000737:chemistry* / Q000191:economics / Q000302:isolation & purification*; D011489:Protein Denaturation; D000074262:Rapeseed Oil; D012639:Seeds / Q000737:chemistry*; D012995:Solubility; D013499:Surface Properties; D013696:Temperature; D014867:Water / Q000032:analysis
chemical_list: D004044:Dietary Proteins; D045703:Emulsifying Agents; D005229:Fatty Acids, Monounsaturated; D007220:Industrial Waste; D010940:Plant Proteins; D000074262:Rapeseed Oil; D014867:Water