Fractionation, physicochemical, and structural characterization of winged bean seed protein fractions with reference to soybean

Proteins from defatted flour winged bean seed (<i>Psophocarpus tetragonolobus</i>) were sequentially fractionated with reference to soybean seed (<i>Glycine max</i>) using distilled water, 25 g/kg sodium chloride solution, 0.1 M NaOH, and 70% alcohol and subjected to physicochemical, functional, and structural analysis. Winged bean seed had globulin (31.94%) and albumin (26.46%), with denaturation temperatures (<i>T</i>_d) of 92.82 and 82.76°C, and surface hydrophobicities (SHs) of 214.51 and 189.32, respectively, whereas soybean seed had 34.95% globulin and 32.82% albumin, with respective <i>T</i>_d of 81.68 and 90.63°C, and SH of 210.80 and 204.66. This indicates that winged bean albumin could perform better at water/oil interface in an oil-in-water emulsion system because of it higher hydrophobicity, although soybean albumin had higher extraction rate. Both legumes’ proteins showed comparable gelation when employed for their gelling ability to form three-dimensional network in food systems. Soybean proteins had significantly (<i>P</i> P <b>Abbreviations:</b> WB: Winged bean; SB: soybean; <i>T</i>_d: denaturation temperature; SH: surface hydrophobicity; SH: surface hydrophobicity; W-ALB: winged bean albumin; W-GLO: winged bean globulin; W-GLU: winged bean glutelin; W-PRO: winged bean prolamin; W-ISO: winged bean isolate; S-ALB: soy albumin; S-GLO: soy globulin; S-GLU: glutelin; S-ISO: soy glutelin and S-PRO: soy prolamin.