Leaf protein concentrate

Leaf protein concentrate (LPC) is a concentrated form of the proteins found in the leaves of plants. It has been examined as a human or animal food source, because it is potentially the cheapest, most abundant source of available protein. Although humans can derive some protein from the direct consumption of leaves as leaf vegetables, the human digestive system would not be able to deal with the enormous bulk of leaves needed to meet dietary protein requirements with leaf vegetables alone.

Application
LPC was first suggested as a human food in the 1960s, but it has not achieved much success, despite early promise. Pirie (1971,1975), the Nobel Prize winner from UK, reviewed and emphasized importance of its benefits which brought the subject forward. The increasing reliance on feedlot based animal rearing to satisfy human appetites for meat has increased demand for cheaper vegetable protein sources. This has recently led to renewed interest in LPC to reduce the use of human-edible vegetable protein sources in animal feed.

Health issues
Leaf protein is a good source of amino acids, with methionine being a limiting factor. Leaf proteins can also be rich in polyphenols. The challenges that have to be overcome before LPC from Lucerne and Cassava, two high density mono-culture crops, becomes a viable protein source for humans include the high fiber content and other antinutritional factors, such as phytate, cyanide and tannins. Leaf for Life, a nonprofit organization dedicated to fighting malnutrition through encouraging increased consumption of vegetables and leaf crops, has extensive information on small scale LPC production using numerous plant species that both do not contain substantial concentrations of the anti-nutrients found in Cassava leaves or Lucerne and from which fiber can be removed through low tech processes.

Methods of production
Generally, LPC is produced by pulping leaves and pressing the juice out, heating the juice to coagulate the protein, and filtering the protein out and drying it.