title: Interfacial and emulsifying properties of lentil protein isolate.
abstract: The dynamic interfacial tension (DIFT) at oil-water interface, diffusion coefficients, surface hydrophobicity, zeta potential and emulsifying properties, including emulsion activity index (EAI), emulsion stability index (ESI) and droplet size of lentil protein isolate (LPI), were measured at different pH and LPI concentration, in order to elucidate its emulsifying behaviour. Sodium caseinate (NaCas), whey protein isolate (WPI), bovine serum albumin (BSA) and lysozyme (Lys) were used as benchmark proteins and their emulsifying property was compared with that of LPI. The speed of diffusion-controlled migration of these proteins to the oil/water interface, was in the following order: NaCas>LPI>WPI>BSA>Lys, while their surface hydrophobicity was in the following order: BSA>LPI>NaCas>WPI>Lys. The EAI of emulsions stabilised by the above proteins ranged from 90.3 to 123.3 m(2)/g and it was 93.3 ± 0.2 m(2)/g in LPI-stabilised emulsion. However, the stability of LPI-stabilised emulsions was slightly lower compared to that of WPI and NaCas-stabilised emulsions at the same protein concentration at pH 7.0. The ESI of LPI emulsions improved substantially with decrease in droplet size when protein concentration was increased (20-30 mg/ml). Reduction of disulphide bonds enhanced both the EAI and ESI compared to untreated samples. Heat treatment of LPI dispersions resulted in poor emulsion stability due to molecular aggregation. The stability of LPI-stabilised emulsions was found to decrease in the presence of NaCl. This study showed that LPI can be as effective emulsifiers of oil-in-water emulsions as are WPI and NaCas at ≥20 mg/ml concentrations both at low and neutral pH. The emulsifying property of LPI can be improved by reducing the intra and inter-disulphide bond by using appropriate reducing agents.
authors.affiliation: School of Health Sciences, University of Ballarat, Mount Helen, VIC 3353, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Joshi
authors.affiliation: School of Health Sciences, University of Ballarat, Mount Helen, VIC 3353, Australia.
authors.forename: B
authors.initials: B
authors.lastname: Adhikari
authors.affiliation: School of Health Sciences, University of Ballarat, Mount Helen, VIC 3353, Australia.
authors.forename: P
authors.initials: P
authors.lastname: Aldred
authors.affiliation: Department of Primary Industries, Horsham, VIC 3401, Australia.
authors.forename: J F
authors.initials: JF
authors.lastname: Panozzo
authors.affiliation: School of Applied Sciences, RMIT University, Melbourne, VIC 3001, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Kasapis
authors.affiliation: School of Life and Environmental Sciences, Deakin University, Geelong, VIC 3217, Australia.
authors.forename: C J
authors.initials: CJ
authors.lastname: Barrow
mesh_terms: D000818:Animals; D002364:Caseins / Q000737:chemistry*; D002417:Cattle; D045703:Emulsifying Agents / Q000737:chemistry*; D004655:Emulsions / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D027806:Lens Plant / Q000378:metabolism*; D008894:Milk Proteins / Q000737:chemistry*; D009113:Muramidase / Q000737:chemistry*; D011492:Protein Hydrolysates / Q000737:chemistry; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D012965:Sodium Chloride / Q000494:pharmacology; D000067816:Whey Proteins / Q000737:chemistry*
chemical_list: D002364:Caseins; D045703:Emulsifying Agents; D004655:Emulsions; D008894:Milk Proteins; D011492:Protein Hydrolysates; D000067816:Whey Proteins; D012710:Serum Albumin, Bovine; D012965:Sodium Chloride; D009113:Muramidase