Waste green parts of plants as raw material for leaf protein concentrate production

Abstract

Leaf protein concentrates (LPC) were obtained from carrot tops, cucumber, mangold and tomato leaves, pea vines and potato haulm using a standard method. Yields of extractable protein per hectare ranged from 45 kg (carrot) to 600 kg (cucumber, potato, tomato). Protein contents of LPC ranged from 22·5% (carrot) to 50% (potato). The former LPC contained an extremely high amount of ash (46·7%). The amino acid compositions of extracted proteins did not differ significantly from those of similar preparations made from other plant species. In contrast to the similar amino acid composition, the nutritive value of the proteins, estimated on rats using the Thomas-Mitchell balance method, differed significantly. The biological value of protein from potato was the lowest (42) and that from cucumber was the highest (59). The leaf-protein digestibilities ranged from 72 to 95% except for protein extracted from carrot tops which was very low (50). Rats fed with tomato LPC died at the beginning of the experiment. Cucumber and pea leaf protein had almost as high net protein utilization as soya bean protein.