Abstract
Fresh alfalfa and its fraction (pressed cake, chloroplastic protein fraction (PF-I), cytoplasmic protein fraction (PF-II) and brown skim), and some leaf protein concentrates (LPCs) which were prepared either from a mixture of alfalfa and barnyard grass (LPC A), a mixture of oat and annual meadow grass (LPC B) or ladino clover (LPC C), were subjected to proximate analysis. The above mentioned LPCs and some other LPC samples such as LPC D from ladino clover, LPC E from alfalfa and LPC F which was obtained by washing LPC E with ethyl alcohol, were also subjected to amino acid analysis. PF-I, LPCs A, C, D, E and F were a representative of the chloroplastic protein, PF-II was that of the cytoplasmic protein and LPC B was a mixture of both. PF-II contained 50.1% crude protein, while PF-I contained 43.2%. Fresh brown skim contained only 1.1% crude protein (21.3% on dry matter basis). PF-I and PF-II, respectively, contained 9.8% and 7.7% ether extracts, 6.5% and 6.4% crude fiber, 18.8% and 16.6% crude ash. The protein fractions contained more lipids and less NFE than the corresponding whole material and the pressed cake. Gross energy of each fraction was very similar, being 19-20kJ/g of dry matter. Legume LPC was much extractable compared to grass LPC, and more purified LPC could be obtained by the laboratory scale procedure than by the practical plant scale procedure. Recoveries of the total amino acids from crude protein were 80%, 89% and 79% in whole alfalfa, PF-I and PF-II, respectively. Compared to the soybean protein, alfalfa and its fractions were low in arginine, aspartic acid, glutamic acid, isoleucine, leucine, phenylalanine, proline and serine and high in alanine, methionine and tryptophan. Histidine was 4 times higher in PF-I than in soybean protein, and in the contrast, arginine content of alfalfa protein was almost one-fourth that of soybean protein. Amino acid composition was not so much different among LPCs though there were some fructuations. When compared to the soybean protein, LPCs were high in alanine, glycine and threonine but low in arginine, aspartic acid, glutamic acid and serine.
