title: Impact of pH on molecular structure and surface properties of lentil legumin-like protein and its application as foam stabilizer.
abstract: The capacity of a protein to form and stabilize foams and emulsions depends on its structural characteristics and its physicochemical properties. The structural properties of lentil legumin-like protein including molecular weight, hydrodynamic size, surface charge and hydrophobicity, and conformation were studied in relation to its air-water interfacial behaviors. Kinetics study suggested that the foaming stability was closely related to the surface conformation of the protein that strongly affected adsorption and re-organization of the protein layer at the air-water interface. Foams prepared at neutral pH showed dense and strong networks at the interface, where combination of the α-helix secondary structure, medium hydrodynamic molecular size, and balance between solubility/hydrophobicity all contributed to the formation of such strong protein network at the interface. At pH 5.0, the protein formed a dense and thick network composed of randomly aggregated protein particles at the air-water interface. Whereas at pH 3.0, the unordered structure increased intra-protein flexibility producing a less compact and relaxed interface that reduces elasticity modulus with time and reduced foam resistance against collapse. This research revealed that lentil legumin-like protein could form long-life foams at mild acidic and neutral pH. The potential for use of lentil protein as a novel foaming plant-based stabilizer is demonstrated in food and non-food applications where stable, long-life foams are required.
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Jarpa-Parra
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, Canada.
authors.forename: F
authors.initials: F
authors.lastname: Bamdad
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, Canada.
authors.forename: Z
authors.initials: Z
authors.lastname: Tian
authors.affiliation: Department of Chemical and Materials Engineering, University of Alberta, Canada.
authors.forename: Hongbo
authors.initials: H
authors.lastname: Zeng
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, Canada.
authors.forename: Feral
authors.initials: F
authors.lastname: Temelli
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, Canada. Electronic address: lingyun.chen@ualberta.ca.
authors.forename: L
authors.initials: L
authors.lastname: Chen
mesh_terms: D006863:Hydrogen-Ion Concentration; D027806:Lens Plant / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D010940:Plant Proteins / Q000737:chemistry*; D011487:Protein Conformation; D012212:Rheology; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D013500:Surface Tension; D000097793:Legumins
chemical_list: D010940:Plant Proteins; D000097793:Legumins
keywords: Conformation; Dilatational; Foaming; Lentil protein; Shear