Chemical characterization and protein quality evaluation of leaf protein concentrates from Glyricidia sepium and Leucaena leucocephala Johnson Oluwasola Agbede* & Valentine Ayobore Aletor Division of Nutritional Biochemistry, Department of Animal Production and Health, Federal University of Technology, P.M.B. 704, Akure, Nigeria (Received 14 May 2002; Accepted in revised form 3 July 2003) Summary 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 dl-methionine 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. Keywords Anti-nutrients, fractionation, nutrients. Introduction Non-conventional protein sources, especially from plant origins, need to be investigated as the food crisis in most countries of Africa, including Nigeria, has greatly aggravated the susceptibility of weanling, pre-school children and other vulner- able groups, to dietary protein and vitamins inadequacies. These inadequacies arise from the high cost of animal proteins (milk, egg and meat) and have, in some developing countries, resulted in kwashiokor, marasmus, infant blindness, mor- tality and morbidity (Tee, 1992). However, one of the immediate panaceas and, perhaps, the cheap- est protein sources can be found in leaf protein concentrates (LPCs) of Glyricidia sepium and Leucaena leucocephala, which have certain agro- nomic and chemical characteristics favouring their use for leaf protein production. Like the cassava leaf (Aletor & Fasuyi, 1997), G. sepium and L. leucocephala have an all-year- round foliage production in sub-Saharan Africa and are rich in protein, minerals and vitamins (Panjaitan, 1988; Onwuka et al., 1992; Aletor & Omodara, 1994; Agbede & Aletor, 1999). Glyricidia sepium is a browse plant with a wide distribution and variation in productivity (Woody & Burley, 1991). In fact, it is the most common and widely used tree in the north coast of Columbia (Sanchez & Moreno, 1992) while it was reported to have severe weed characteristics in Jamaica (Holm et al., 1979; Hughes & Style, 1984). It is also found in Indonesia where its leaves are considered to be of high protein content (Panjaitan, 1988). Glyricidia sepium is a small to medium sized thorn-less tree that usually attains a height of 10–12 m. While the temperature require- ments are not too specific (20.7–29.2 °C) it has been reported to grow well in climatic areas with minimum rainfall of 3781.0 mm per annum (Hughes & Style, 1984), with high but sustainable biomass production. Leucaena leucocephala is a tropical leguminous plant whose origin has been traced to Mexico and *Correspondent: e-mail: joagbede@yahoo.com International Journal of Food Science and Technology 2004, 39, 253–261 253 doi:10.1111/j.1365-2621.2004.00779.x Ó 2004 Blackwell Publishing Ltd