Leaf protein concentrate
Trees are generally considered a poor source of leaf mass for the production of LPC given restrictions on the ease of access.
Other non-traditional sources include agricultural wastes such as pea (Pisum sativum) pods, cauliflower (Brassica oleracea) leaves, as well as invasive plants such as gorse (Ulex europeaus), broom (Cytisus scoparius), and bracken (Pteridium aquilinum).
Enzyme treatment is another well reported method which targets the plant cell wall to aid the release of bound proteins.
Heat coagulation is the easiest and the oldest method of protein recovery, albeit the least preferred as most of the nutritive value of the LPC is lost.
Acid precipitation is the most commonly employed method of protein recovery although it results in the loss of methionine and tryptophan in the LPC.
Solvent precipitation is not often reported although it produces the highest protein recovery among other methods and preserves the nutritional integrity of the LPC.
Interestingly, the purity of the final LPC was influenced by the protein content in the initial leaf mass rather than the purification method employed.
[12] Telek on the other hand experimented with numerous tropical plants at a large scale using a combination of pulping and heat coagulation.
He and his team developed machines for extraction of LPC, including low-maintenance "village units" intended for poor rural communities.
[20] The non profit organization, Leaf for Life, maintains a list of human edible leaves and provides recommendations for the top choices of plants.
This has recently led to renewed interest in LPC to reduce the use of human-edible vegetable protein sources in animal feed.
[27] For testing new leaf species for use as LPCs a non-targeted approach has been developed that uses an ultra-high-resolution hybrid ion trap orbitrap mass spectrometer with electrospray ionization coupled to an ultra-high pressure two-dimensional liquid chromatograph system.
[50] The process uses three tools: 1) mass spectrometry analysis with MZmine 2,[51][52] 2) formula assignment with MFAssignR,[53][54] and 3) data filtering with ToxAssign.
