Jatropha Curcas – Background Information
- Scientific name: Jatropha curcas
- Common names: Physic nut, purging nut
- Family: Euphorbiaceae
- Origin: Mexico and Central America (??)
- Occurs wildly in almost all tropical and sub-tropical countries of the world
- Perennial shrub – grows up to about 5-6m height
- Grows well in warm tropical climates
- Plant is drought tolerant, adaptable and thrives on nutrient poor soils
- Flowering and fruiting seasonal usually connected to the rainy seasons
- Fruits containing 2-4 seeds, usually 3.
- Dry fruit weighs about 2.5g, 60% weight seeds and 40% weight fruit husk
- The seeds contain about 37.5% by weight shell, 30-40% oil and the rest mostly protein
- Two varieties of Jatropha curcas occur naturally: conventional non-edible jatropha plants and a phenotypically similar, but edible variety called Xuta, which lacks compounds called phorbol esters present in the non-edible varieties.
- Traditional uses: fence plant around small farms, medicinal purpose, edible variety (called Xuta in Mexico) used as human food in Mexico
- Pollination is by insects, usually honey bees
- The plant, even the edible variety, is non-edible to grazing animals, but honey produced from it is edible
- Conventional, non-edible Jatropha plants are familiar backyard and fence plants in many countries and people are familiar with it and its non-edible nature.
Jatropha plantation products
Pruned biomass:
to keep the plants at a height of about 2m, pruning would be required every year. Depending on plant nature and size between 1.5 and 5kg dry matter would be generated from 1 plant through pruning
Jatropha fruit fractions:
the major production item from the jatropha plantation are the fruits. They yield the following fractions on processing.
Freshly harvested fruits
Dried fruits – 3 days of sun drying
Fruit Husks
The fruits can be mechanically shelled using simple locally made machinery. Both fresh and dried fruits can be de-husked. The wet husk is ideal for mulching the plantation. For dry fruits mulch forms about 40% w/w. Dry husk has an energy content of 14MJ per kg and can be used as burning fuel.
The seeds form 60% /w of the dried fruits. They can be mechanically shelled into Shell and kernel.
Jatropha shell (mechanically shelled) forms about 37.5% of the dry seed. It has a high energy content of 18MJ/kg and is a good burning fuel.
Kernel forms about 62.5% of the dry seeds and can be crushed to separate oil and kernel meal.
Jatropha oil forms about 60% w/w of the kernel and is an ideally fuel oil and feed stock for bio-diesel and bio-aviation-fuel. Edible jatropha oil has potential to become an ideal edible oil.
Average fatty acid composition (%) of Jatropha curcas seed oil
| Oleic acid (C-18:1) | 35-51% |
| Linoleic acid (C-18:2) | 27-42% |
| Palmitic acid (C-16:0) | 9-22% |
| Stearic acid (C-18:0) | 5-8% |
| Arachidic acid (C-20:0) | 0-2% |
| Myristic acid (C-14:0) | 0-2% |
| Palmitoleic acid (C-16:1) | 0-1% |
Typical physical/chemical properties of Jatropha curcas seed oil
| Calorific value | 37.8 MJ/kg |
| Appearance | Light yellow liquid |
| Specific gravity at 30°/30° | 0.92 |
| Acid value | 1.24 |
| Saponification value | 197 |
| Iodine value | 102 |
| Unsaponifiable matter | 0.004 |
Edible jatropha kernel cake forms about 40% w/w of jatropha kernels, contains about 60% crude protein and is an ideal animal and fish feed ingredient. Its protein have a high nutritional quality also for humans.
Conventional non-edible jatropha seeds are crushed without deshelling, yielding about 28% w/w of oil and the rest seed cake. This contains 3-4.5% N, 0.65-1.2% P2O5, 0.8-1.4% K2O and 0.2-0.35% S and has been scientifically proven to be an excellent organic fertilizer. The phorbol esters present in the seed cake act as a biological pesticide particularly against soil nematodes, slugs and snails that are harmful to plants.