The Bulk Extraction and Quality of Leaf Protein

  • N. W. Pirie
Part of the Modern Methods of Plant Analysis book series (MOLMETHPLANT, volume 16)


Whether concern is directed towards the needs of a less-developed country with a food shortage, the problems of a country where there is a surplus of grain while fishmeal and oilseed residues are imported as feed for pigs and poultry, or towards the more general matter of making farming more efficient, protein extracted from leaves (LP) deserves attention. There are many reasons for this, for example:
  1. 1.

    Leaves are the primary site of protein synthesis and protein is lost when translocated to seeds or tubers.

  2. 2.

    Suitable crops maintain a photosynthetically active cover throughout the period in which growth is possible. Yields are therefore greater than with any other type of crop. LP is therefore potentially the most abundant source of protein. Conventional leafy vegetables share this merit. Increased use of them would be advantageous, but the amount of fibre which accompanies the protein in them sets a limit to consumption.

  3. 3.

    Ruminants return as human food only 5 to 30% of the protein they eat, whereas 50 to 60% of the protein in a leaf crop can be extracted.

  4. 4.

    Species rejected as human or animal food because of texture or toxicity can be used as LP sources. When the LP is washed, flavour and toxic material are usually removed. Ruminants readily eat the extracted residue and do well on it, because, coming from young plants, it is less lignified than a crop which, untreated, has the same N content. Because it has been pressed, there is no drip when it is ensiled, and less fuel is needed than with a normal crop to dry it completely for use as winter feed.

  5. 5.

    If made carefully, LP is nutritionally better than the usual seed proteins; but not as good as egg or milk. Like other proteins which contain carbohydrates and unsaturated fats, it is damaged by inept handling.

  6. 6.

    Extraction equipment can be simple enough for use in villages; equipment for large-scale extraction has also been designed.

  7. 7.

    People with European or North American prejudices find the appearance of LP unusual at first. They soon accept it, and no problems with acceptance have been met anywhere where it has been intelligently presented.



Water Hyacinth Leaf Protein Press Cake International Biological Program Leaf Meal 
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