Adsorption of Speckled Sugar bean protein isolate at oil-water interface: Effect of ionic strength and pH.
Speckled Sugar bean protein (0-4%) was used to stabilize sunflower oil in water emulsion (30% oil). To investigate the effect of other components on emulsion properties different salt concentrations (0-0.5M) and pH (3-7) were used. For this purpose, zeta potential, oil droplet size, adsorbed protein, non-adsorbed protein, viscosity, emulsifying capacity, emulsion stability and creaming rate were evaluated. Results showed that protein concentration was the most effective variable affected emulsions characteristics followed by protein-pH interaction as the second effective term. Salt somehow influenced emulsion properties but it had no negative effect on emulsifying capacity, emulsion stability or creaming rate. FTIR spectroscopy revealed that protein fractions with higher sheet secondary structure had better adsorption on oil droplets; while, fractions with helix subunit as the predominant secondary structure had the lowest adsorption capacity. At the end, emulsion properties were optimized based on the different independent and dependent variables. Results confirmed that Speckled Sugar bean protein was resistant to aggregation at high ionic strength. As a result, this protein could perform well as an emulsifier at different pH values.
Department of Food Science and Technology, Ferdowsi University of Mashhad (FUM), PO Box 91775-1163, Mashhad, Iran.
Nazanin Fatemeh
NF
Rahmati
Department of Food Science and Technology, Ferdowsi University of Mashhad (FUM), PO Box 91775-1163, Mashhad, Iran. Electronic address: koocheki@um.ac.ir.
Arash
A
Koocheki
Department of Food Science and Technology, Ferdowsi University of Mashhad (FUM), PO Box 91775-1163, Mashhad, Iran.
Mehdi
M
Varidi
Department of Food Nanotechnology, Research Institute of Food Science and Technology, PO Box: 91735-147, Mashhad, Iran.
Rassoul
R
Kadkhodaee
D000327:Adsorption; D045703:Emulsifying Agents / Q000737:chemistry* / Q000302:isolation & purification; D004655:Emulsions; D005163:Factor Analysis, Statistical; D005524:Food Technology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009994:Osmolar Concentration; D027805:Phaseolus / Q000737:chemistry*; D010938:Plant Oils / Q000737:chemistry*; D010940:Plant Proteins / Q000737:chemistry* / Q000302:isolation & purification; D017433:Protein Structure, Secondary; D012965:Sodium Chloride / Q000737:chemistry*; D000074242:Sunflower Oil; D014783:Viscosity; D014867:Water / Q000737:chemistry*
D045703:Emulsifying Agents; D004655:Emulsions; D010938:Plant Oils; D010940:Plant Proteins; D000074242:Sunflower Oil; D014867:Water; D012965:Sodium Chloride
Emulsion; Protein; Salt; Speckled Sugar bean; pH