Nearly every community uses oil in cooking. In some cases oil is a primary ingredient for flavor and energy, delivering needed calories and fats in a concentrated form (while in North America many people are concerned about limiting oil in their diets). Because processing equipment, oil crops, or both are frequently not available in a particular community, oil must be imported from elsewhere in-country if not from abroad. Development workers often write us with questions about producing oil locally in their communities. In future issues of EDN we hope to address this subject in more detail; these articles are an introduction to the topic. 2 - Oils CHAPTER 16: OILS OIL CROPS Buffalo Gourd is Another Candidate for Food and Fuel Cucurbit Seeds as Possible Oil and Protein Sources for Small-Scale Household Use in the Hot Humid Tropics, by Dr. Frank Martin Egusi Seeds are High in Oil and Protein Jojoba in Perspective Vernonia galamensis: A Potential New Industrial Oil Crop for Semi-Arid Areas of the Tropics and Subtropics OIL PROCESSING Back Issues of "Oilseed Press" Available How Can I Get Palm Oil from Oil Palms? Castor Bean Oil A Few Small-Scale Press Resources and Manufacturers Oils - 3 BUFFALO GOURD IS ANOTHER CANDIDATE FOR FOOD AND FUEL. ECHO has grown buffalo gourds in our "semi-arid" greenhouse for several years. Until recently I was not overly enthused about it, even though it is one of the National Academy of Sciences "underexploited" plants. It has some impressive traits, but I did not imagine that many in our network would actually use it. My enthusiasm took a quantum leap when Dave Unander told me about the work of Drs. Wayne Bragg and Eugene Schultz and Debra Duke on its use as a cooking fuel. Wayne says that within a few years the plant can develop a "colony" that covers an area 35 feet across and roots of the original plant can be nearly as large as a person. By then the roots are too difficult to dig and the "mother plant" soaks up all available water. Consequently he harvests most roots about 3 months after planting, at which time they may be the size of a large carrot. He leaves a few plants because wherever a bit of soil and water is placed over the sprawling vine, roots will develop. 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Wayne and colleagues found that they can harvest more biomass from the roots (11 metric tons per hectare in 3 months) than from limbs of the common dryland firewood tree crop, mesquite (6 metric tons per hectare in 12 months). Roots are cut into thin segments, with some thin slivers, and sun dried. Roots are slower to ignite than wood, which is where the slivers help. Frequent feeding with small charges of roots is desirable. Size of the grate openings may need to be increased, as the root fuel requires more draft than wood. With enough air they produce no more smoke than wood, but do produce more ash. Like wood, roots burn with flames until about 80% consumed, then coals burn at a lower rate. Flames are about half as high as wood (charcoal has no flames). Roots burn a third as fast as wood but 3.7 times as fast as charcoal. Because of lower heating value than charcoal they only release heat 1.6 times as fast as charcoal, but water can be heated about twice as fast as on a charcoal fire. The authors attribute this to efficiency of capture of heat from a root fire being about 1.25 times greater than from charcoal. Cooking tests with women in Mexico, Niger and Senegal have been positive and some communities are now using rootfuel in Mexico. They say the smoke is not irritating. ECHO has seed if you would like to try this plant. do not request the seed if you have a long humid season with plenty of water; other crops are much better. We have never been able to keep a plant alive at ECHO through the summer, even in our semi-arid greenhouse. CUCURBIT SEEDS AS POSSIBLE OIL AND PROTEIN SOURCES FOR SMALL-SCALE HOUSEHOLD USE IN THE HOT HUMID TROPICS. Dr. Frank Martin wrote an article on this topic for us. You may have a copy upon request. Here is a summary of the highlights. Oils are necessary in the diet as a source of non-saturated fatty acids. They also are a concentrated source of energy, give flavor to foods and are used as a cooking medium in the kitchen. How can oils be produced at the level of the individual household in the tropics? On a small scale, animal fats are more easily obtained from small animals than plant fats can be obtained from plants. Animal fats can be stored 1-2 weeks or more without refrigeration, but plant fats are less stable and more readily turn rancid. Most plant fats contain a good proportion of non-saturated fatty acids (palm oils are an exception) and are therefore more useful nutritionally. Most plant oils are stored in the seeds. It is not necessary to extract the oil to obtain its nutritional value, but this is often desirable for other reasons. It is also often desirable to remove the hulls. A convenient way to use the fats without first extracting them is to prepare a vegetable curd. This is done by grinding the seeds in water, filtering, and precipitating the protein with an appropriate agent, such as lime juice, vinegar or epsom salts. Most of the oil comes out with the protein. In the tropics there is often a shortage of oil in the diet and/or cooking oil for the kitchen. It is difficult to mature many of the most typical oil crops during the rainy season. A suitable crop for small scale oil production in the tropics 4 - Oils should be an annual, or a perennial that produces during the first or second year. The oil producing fruit or seed should be available year round or the seed should be storable for oil production year round. It is also useful if the seeds are also good sources of protein. The oil palm outproduces all other species. Its oil is principally saturated. The coconut palm is also excellent. The oil can be extracted at the household level. Because of the space and time required, however, they may not be convenient crops for the small household. The soybean, peanut and possibly winged bean are suitable for high quality cooking oil, but are very difficult to extract on a small scale. They are excellent sources of non-saturated fatty acids. Okra seed is another possibility. There are many precedents for using cucurbit seeds for oil in the tropics. Two value.somequitetheiracids,aboutproteinucurbitCucurbitsquashes,s.oproteinsin lysine usefuloil cucurbit 50%thus Conjugatedafter seeds are is seeds pumpkins] oilofasnondehulling.typicallyand dryingoilsashighand- saturated [e.g.fatty oil sulfur makeupnutritional oils. deficient sources.Mostmelons,acidstocontain them fatty35%Theam of species of Telfaria (oyster nut) are used for their large oily seeds in Africa. Hodgsonia (lard fruit) is a perennial vine with large, fatty seeds that has been domesticated as an oil source in China. In West Africa, seeds of watermelon are used as commercial sources of oil. These and seeds of egusi and bottle gourd are used in melon soups for their oil and protein content. (Seeds of Luffa acutangula and L. cylindrica, the angled and sponge luffa gourds, are bitter and may be poisonous.) Most cucurbits cannot be grown except when there is a pronounced dry season because of disease problems. The most successful species for the humid tropics, from our experience in Puerto Rico, are Benincasa hispida, the wax gourd, and Cucurbita moschata, the tropical pumpkin. If fruits are carefully protected from excess moisture, Lagenaria siceraria, the bottle gourd, can also be grown. The wax gourd is perhaps the best of the cucurbits as a source of seed oil for the hot, humid tropics. It can be produced any season of the year. Though the fruits may rot during the rainy season, they can be protected by growing the vines on trellises or by placing thick but porous supports between the fruit and the wet ground. The fruits are very large and very seedy. If the fruits are sound, they can be stored for many months, even a full year, until used. Or, the seeds can be removed and dried. Per hectare yields of seeds have been estimated in our fields as 500 kg/ha. [Ed: The fruits of some varieties are covered with a white wax that keeps microorganisms from attacking. The white flesh is eaten much as a summer squash, though is somewhat more firm.] Seeds of cucurbits can usually be readily separated from the pulp. Sometimes a light fermentation of the wet seeds for 1-3 days is useful to clean the pulp from the seeds. Fresh, wet seeds can be chewed without further processing or are toasted.