Structural changes and functional characteristics of common vetch isolate proteins altered by different pH-shifting...

To investigate protein structure and functional changes, common vetch protein isolate (CVPI) during pH-shifting were performed. Results showed secondary and tertiary structures of CVPI were improved during these treatments compared with the pH 7.0. Scanning electron microscopy showed the microstructure was changed from lamellar to spherical granular and rod-like structure during pH - shifting. Under 8 pH treatments (pH 2.0, 3.0, 12.0, 2.0 → 7.0, 3.0 → 7.0, 12.0 → 7.0, 11.0 → 9.0 and 11.0 → 7.0), the average particle sizes were smaller and from 82 to 146 nm. Under 8 pH treatments (pH 2.0, 3.0, 11.0, 12.0, 11.0 → 9.0, 11.0 → 7.0,12.0 → 9.0 and 12.0 → 7.0), the protein solubility was higher and from 63 to 86 %. Under 3 pH treatments (pH 2.0, 11.0 and 12.0), the emulsion activity index and emulsion stability index was higher and from 40 to 60 m²/g and from 54 to 97 min. Under 5 pH treatments (pH 2.0, 12.0, 11.0 → 9.0, 12.0 → 9.0 and 12.0 → 7.0), the foaming capacity and foaming stability was higher and from 145 to 185 % and from 67 to 82 %. Therefore, the pH - shifting treatment gave the CVPI improved characteristics in structural and functional properties.