Extraction, composition, and functional properties of dried alfalfa (Medicago sativa L.) leaf protein

Abstract BACKGROUND Alfalfa is considered a potential feedstock for biofuels; co‐products with value‐added uses would enhance process viability. This work evaluated dried alfalfa leaves for protein production and describes the functional properties of the protein. RESULTS Dried alfalfa leaves contained 260 g kg −1 dry basis ( DB ) crude protein, with albumins being the major fraction (260 g kg −1 of total protein). Alkali solubilization for 2 h at 50 °C, acid precipitation, dialysis, and freeze‐drying produced a protein concentrate (600 g kg −1 DB crude protein). Alfalfa leaf protein concentrate showed moderate solubility (maximum 500 g kg −1 soluble protein from pH 5.5 to 10), excellent emulsifying properties (activity 158–219 m 2 g −1 protein, stability 17–49 min) and minimal loss of solubility during heating at pH ≥ 7.0. CONCLUSIONS It is technically feasible to extract protein with desirable emulsifying and heat stability properties from dried alfalfa leaves; however, the dried form may not be a practical starting material for protein production, given the difficulty of achieving high yields and high‐purity protein product. © 2016 Society of Chemical Industry