Jatropha – Oil for Biofuels and Meal for Livestock Feed: Risk Management in the Right Places
Demand for diesel fuel continues to grow. As such, this is reflected by higher prices. This effect is exacerbated in places with notable populations, a strong dependence on foreign sources of oil, and a geographically-remote location like the islands of Hawaii. As an example, compare diesel prices in Hawaii to Iowa.
Similar situations are encountered with food – a gallon of organic milk in Hawaii costs as much as a bottle of wine, and non-organic milk is nearly double the price of the same volume in New York City. Along the same lines, Hawaii has two remaining cow dairies on the islands, which rely on the importation of several feed ingredients. Most milk is shipped in from California.
Isolated places with sizeable populations, and demand for products, create interesting opportunities. Jatropha, a flowering plant native to the tropics (shown in the image above), may be helpful in these situations. The plant can grow in many different soil types, and thrive on only 10 inches of rain per year. In addition, Jatropha produces high yields after 2-3 years, and can continue producing for several decades. The seed is high in oil (we have data indicating 39% oil content), which can be extracted and used for biodiesel production.
After oil extraction, the resulting oil cake can be ground into meal for livestock feed. It appears to be important to use the non-toxic variety from Papantla (Mexico) for this purpose, as it is naturally low in toxic phorbol esters. However, even this variety still contains antinutrients, such as trypsin inhibitors, lectins, and phytate. So, all Jatropha meals would seem to benefit from some sort of heat processing before feeding. However, a feeding study with rats determined that roasted Jatropha seed meal was not superior to unroasted meal, and both were inferior to soybean meal (Panigrahi et al., 1984). In the study, roasting (heating for 200oC for 30 minutes) reduced the amino acid content of Jatropha meal. In a more recent study, heating (121oC) along with moisture addition for 15 minutes reduced antinutrients, but this only marginally increased the growth rate of farmed carp (versus unheated Jatropha meal). Heating for 45 minutes reduced growth performance almost certainly due to protein damage, as protein efficiency ratios were reduced.
It would seem that dry extrusion would be a better choice for processing Jatropha, not only for feed, but also for oil extraction. Dry extrusion is high temperature, short time (seconds) processing that ruptures plant cell walls and liberates its contents (oil, protein, and so on). It has been used for decades to process soybeans, resulting in high-quality protein and oil, with reduced antinutrients. It has also been successfully combined with mechanical oil pressing to isolate oil from a variety of crops.
Dry extrusion generates heat from friction only (from within the extruder), and can be used almost anywhere in the world. In addition, dry extruders are relatively inexpensive, easy to operate, and cheap to maintain. They do not require chemicals or solvents that must be contained and eventually disposed, and along with mechanical oil presses that squeeze out the oil, make up a very natural processing choice.
So, appropriate cropping systems, such as Jatropha, combined with dry extrusion and mechanical oil pressing, may be great choices to manage the risk of fuel and food uncertainty in the right parts of the world. Insta-Pro International’s R&D group would be happy to work with interested parties, as we have with mechanical oil pressing of Jatropha at the Oceanic Institute in Hawaii. Mutually-beneficial arrangements could be made if, for example, a supply of Jatropha (or similar crop, such as Pongamia) seeds could be sent to our extrusion-oil pressing R&D center in suburban Des Moines, Iowa. Please contact us to discuss further.
Reference: Panigrahi, S., B.J. Francis, L.A. Cano, and M.B. Burbage. 1984. Toxicity of Jatropha Curcas Seeds from Mexico to Rats and Mice. Nutrition Reports International. 29(5):1089