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

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 degrees 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. (C) 2016 Society of Chemical Industry