Composition, Structure, and Techno-Functional Characteristics of the Flour, Protein Concentrate, and Protein Isolate from Purslane (Portulaca oleracea L.) Seeds

One potential avenue to increase the production of valuable protein ingredients for the food industry is developing vegetable proteins from non-traditional plant sources. In the present study, the composition, structure and techno-functional characteristics of defatted purslane flour (DF), protein concentrate (PC), and protein isolate (AP) were investigated. The results revealed that DF, PC, and PI contained low levels of moisture, ash, and fat. However, there were significant differences (P < 0.05) in protein content between DF, PC, and PI (32.9, 60.8 and 90.9%, respectively). The techno-functional characteristics of purslane proteins were enhanced by processing purslane flour into PC and PI products. Furthermore, the ratios of total essential amino acids to total amino acids in purslane protein samples were well above that stated for ideal food proteins. SDS-PAGE analysis indicated three subunits of protein in DF, PC, and PI. Scanning electron microscopy revealed that DF exhibited a compact-like structure; PC had a small, flaky, but porous type of particle, and PI had an intact flake-like structure. The FTIR analysis revealed that some alterations in the secondary structure of protein were occurred. In summary, purslane proteins can be considered new functional food ingredients with different nutritional and technological characteristics.