Plant proteins from green pea and chickpea: Extraction, fractionation, structural characterization and functional properties

The value of pulse grain has been drastically increased by manufacturing it to pulse storage protein isolates. The utilization of pulse proteins is highly dependent on the composition, functional and structural properties. Therefore, the current study was conducted to investigated the structural and functional attributes, as well as the aroma profile of major fractions of pulse storage proteins isolated from green pea and chickpea including globulin, legumin, and vicilin. Alkaline extraction-isoelectric precipitation in conjunction with a modified salt dissolution-precipitation method was developed to produce abovementioned protein fractions in a large scale. Results showed that purity of globulin, legumin and vicilin fractions reached more than 90%, 80%, and 90%, respectively. Regarding the functionality of protein fractions, protein compositions had significant impacts on the structural and functional properties of proteins. In general, vicilin fractions had higher solubility, and foaming and emulsification properties but lower thermal properties compared to legumin fractions because of its lower molecular weight, less rigid conformational structure, and lower disulfide bond content. However, aromatic compound profile of protein fractions was strongly affected by pulse types as both lipid and lipoxygenase contents varied depending on the type of pulses. Overall, chickpea protein fractions contained higher typical beany aromatic compounds (e.g., 1-pentanol, 1-ocetn-3-ol, and hexanal) than green pea protein fractions. These results can greatly extend the knowledge for better understanding the structural and functional properties of pulse proteins.