Composition and Functional Properties of Hemp Seed Protein Isolates from Various Hemp Cultivars

Hemp seed protein isolates (HPI) were extracted from the seeds of seven commercial hemp cultivars, a Cornell breeding line, and a commercial hemp heart product. The composition and functional properties of the resulting HPI were investigated. HPI were of high protein purity >96% and contained various ratios of the major protein classes edestin, vicilin, and albumin, depending on the source. Protein solubility varied across HPI, and there was a positive correlation between greater levels of vicilin and albumin and improved solubility. The isoelectric points of HPI ranged from 5.50 to 5.94 but did not show significant effects associated with major protein class ratio. Significant differences in HPI foam capacity (52.9-84.9%), foam stability (68.1-89.4%), water holding capacity (0.83-1.05 g water/g protein isolate), and oil holding capacity (1.28-1.81 g oil/g protein isolate) were observed. In general, the emulsions generated from HPI performed poorly in terms of emulsifying activity, stability, and emulsion particle size. The ratio of edestin, vicilin, and albumin was found to play a major role in HPI functionality, suggesting that certain hemp cultivars may be better suited for generating protein ingredients that can functionalize plant-based foods.