title: Influence of extraction pH on the foaming, emulsification, oil-binding and visco-elastic properties of marama protein.
abstract: BACKGROUND
  Marama bean protein, as extracted previously at pH 8, forms a viscous, adhesive and extensible dough. To obtain a protein isolate with optimum functional properties, protein extraction under slightly acidic conditions (pH 6) was investigated.
  
  
  RESULTS
  Two-dimensional electrophoresis showed that pH 6 extracted marama protein lacked some basic 11S legumin polypeptides, present in pH 8 extracted protein. However, it additionally contained acidic high molecular weight polypeptides (∼180 kDa), which were disulfide crosslinked into larger proteins. pH 6 extracted marama proteins had similar emulsification properties to soy protein isolate and several times higher foaming capacity than pH 8 extracted protein, egg white and soy protein isolate. pH 6 extracted protein dough was more elastic than pH 8 extracted protein, approaching the elasticity of wheat gluten.
  
  
  CONCLUSIONS
  Marama protein extracted at pH 6 has excellent food-type functional properties, probably because it lacks some 11S polypeptides but has additional high molecular weight proteins. © 2017 Society of Chemical Industry.
authors.affiliation: Institute for Food, Nutrition and Well-being and Department of Food Science, University of Pretoria, Hatfield, South Africa.|UCD Institute of Food and Health, University College Dublin, Dublin, Ireland.
authors.forename: Muhammad
authors.identifier: http://orcid.org/0000-0002-6145-0756
authors.initials: M
authors.lastname: Gulzar
authors.affiliation: Institute for Food, Nutrition and Well-being and Department of Food Science, University of Pretoria, Hatfield, South Africa.
authors.forename: John Rn
authors.initials: JR
authors.lastname: Taylor
authors.affiliation: Institute for Food, Nutrition and Well-being and Department of Food Science, University of Pretoria, Hatfield, South Africa.
authors.forename: Amanda
authors.initials: A
authors.lastname: Minnaar
mesh_terms: D055598:Chemical Phenomena; D004220:Disulfides / Q000737:chemistry; D004548:Elasticity; D004655:Emulsions / Q000737:chemistry; D007887:Fabaceae / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D055595:Mechanical Phenomena; D010940:Plant Proteins / Q000737:chemistry* / Q000302:isolation & purification*; D000074262:Rapeseed Oil / Q000737:chemistry; D030262:Soybean Proteins / Q000737:chemistry; D014783:Viscosity
chemical_list: D004220:Disulfides; D004655:Emulsions; D010940:Plant Proteins; D000074262:Rapeseed Oil; D030262:Soybean Proteins
keywords: dough visco-elasticity; emulsification; extraction pH; foaming; marama proteins; oil binding