Chemical characterization and protein quality evaluation of leaf protein concentrates from Glyricidia sepium and Leucaena leucocephala

Leaves and leaf protein concentrates (LPCs) from leaves of Glyricidia sepium and Leucaena leucocephala were analysed for chemical constituents. The protein quality of the LPC, with or without dlmethionine supplementation, was estimated by using sixty weanling albino rats. Glyricidia leaves contained higher crude protein and lower crude fibre than L. leucocephala leaves, while the ash values were identical. In the LPCs, crude protein showed a good balance of amino acids and nutritionally important minerals. The gross energy (GE) was only enhanced in the LPC of Glyricidia and, although tannin content was reduced in the LPCs, the phytate concentration increased. The rat bioassay did not suggest that, even when supplemented with dl-methionine, Glyricidia or Leucaena LPC would support rat growth when used as the sole sources of dietary protein. Based on the analytical and bioassay data, the nutritional potentials and limitations of these under-utilized protein resources are discussed.