Comparison of the physicochemical and functional properties of flour and protein isolate from moringa (Moringa oleifera Lam.) leaves

The physicochemical and functional properties of flour (MF) and a protein isolate (MPI) obtained from moring leaves were evaluated and compared. These properties were evaluated and compared with a commercial soybean protein isolate (SPI). MPI was obtained by alkaline solubilization at pH 11.5 and isoelectric precipitation at pH 4.5. The protein content of MPI was 75.8%, with a yield of 6.5% when obtained by lyophilization. Electrophoresis analysis confirmed the presence of proteins between 8 and 120 kDa, and FTIR analysis confirmed the yield of MPI and the decrease of non-protein constituents, such as carbohydrates. The MF showed good gelation properties [5 mL (100%) at 14% (w/v) flour]. MPI showed even better gelling properties (10% to 78%) than SPI and similar water and oil absorption capacities (WAC and OAC) (3 g g-1 and 1.5 g g-1 respectively) as SPI. The pH had a significant influence on these properties. It can be concluded that MPI is an important protein source and may be a viable alternative as a functional food ingredient comparable to SPI in some properties such as WAC, OAC, and emulsion stability at low pH.