Impact of enzyme-assisted structural modification on the volatile profiles, functionality and digestibility of pea protein isolates

This study investigated the effect of five different enzyme-assisted alkaline extractions on the structural and functional properties, and digestibility of pea protein isolates. The enzymes induced structural and compositional changes to the pea proteins, enhancing both the functionality and digestibility of the resulting isolates compared to the control. The level of hydrolysis was consistent across all enzyme treatments, ranging moderately between 15.9%–16.1%. Significant differences (p < 0.05) were observed in protein solubility among the isolates, which ranged from 55.6-75.2%. In general, most isolates showed improved or similar, water holding (1.6-2.2 g/g), oil holding (0.9-1.4 g/g), emulsion capacity (80.0-100.0%), foaming capacity (226.6-292.8%), and digestibility (85.7-87.8%) compared to the isolate produced without enzyme modification. The results of the Sodium dodecyl-sulphate polyacrylamide gel electrophoresis (SDS-PAGE) primarily identified the protein in the isolates as globulins and further classified these into 11S legumin, 7S vicilin, and convicilin. Enzyme modification reduced undesirable volatile compounds associated with unpleasant flavors and introduced a range of favorable new volatile compounds such as oximes, benzaldehyde compounds, and ketones. These favorable compounds were absent in the isolate produced without enzyme modification, emphasizing the practical benefits of enzyme-assisted extraction.