By Ray Hansen, content specialist, AgMRC, Iowa State University, email@example.com.
Revised August 2011 by Diane Huntrods, AgMRC, Iowa State University.
Sesame (Sesamun indicum), an ancient oilseed, is one of the oldest cultivated plants in the world. This warm-season annual crop is primarily adapted to areas with long growing seasons and well-drained soils and has spread from its center or origin in Iraq to many parts of the world.
Historical documentation suggests that Thomas Jefferson grew sesame seed in test plots more than 200 years ago. He referred to it as beni or benne, the name used in Africa. Sesame was introduced to the United States in the 1930s. The first U.S. commercial production began in the 1950s.
Through the ages, sesame seeds have been a source of food and oil. About 65 percent of the annual sesame crop is processed into oil and 35 percent is used in food. The food segment includes about 42 percent roasted sesame, 36 percent washed sesame, 12 percent ground sesame and 10 percent roasted sesame seed with salt.
The small sesame seed is used whole in cooking for its rich nutty flavor (although such heating damages its healthful polyunsaturated fats) and also yields sesame oil. Most of the U.S. sesame crop is sold as some form of whole seed product for the confection and baking industries. Less than 10 percent of total production is processed into oil, meal or flour.
Sesame seeds are small; one thousand weigh about one ounce. The seeds also vary in color. The two main colors are white and black. White sesame seed is grown in Mexico, Guatemala and El Salvador while black sesame comes from China and Thailand. The lighter colored seeds are considered higher quality.
Sesame seed is approximately 50 percent oil and 45 percent meal. It is unusually high in oil; soybeans are only 20 percent oil. Because protein content and oil content are inversely proportional, seeds with an increased oil content have a decreased protein content.
Whether hulled or dehulled, roasted or raw, the seeds are now widely used in baking, candy making and other food products. The bakery industry prefers de-hulled seeds. The hulls surrounding the seed are removed in a wet process and the hulls are discarded. The bare seed is then washed and dried to produce a premium confectionary product. This de-hulled seed makes up 50 percent of the U.S. market.
Tahini, a traditional Mideast sesame paste and the peanut butter equivalent of sesame, is made from hulled sesame seed. The paste is rich in protein and a very good energy source. Dip and spread manufacturers use tahini in conjunction with chickpeas to produce hummus and with egg plant to produce baba ganouj. Halva production is a subset of this industry. Halva is a popular sweet made by mixing approximately 50 percent tahini with boiled and whipped sugar and several other ingredients to form a popular Middle Eastern confection.
Additional products sold in U.S. grocery and health food stores with sesame seed as an ingredient include sesame crackers, whole grain and sesame cereals, sesame chips and sesame seed candy.
Commercially, sesame oil comes in two basic types. One type of sesame oil is a pale yellow liquid and has a pleasant grain-like odor and somewhat nutty taste. This oil is high in polyunsaturated fats, ranking fourth behind safflower, soybean and corn oil. It is excellent for use as frying oil, in cosmetics and in food preparations. The other type of oil is amber-colored and aromatic, made from pressed and toasted sesame seeds. This popular ingredient in ethnic cooking is not used as a cooking oil, however, because the flavor is too intense and it burns quite easily. Instead, sesame oil is normally added as a flavoring agent in the final stages of cooking.
Oil is extracted from sesame seeds by mechanical pressing. The seed may be cold pressed to give an aromatic salad oil or hot pressed to give a lower grade product. The oil yield is from 50 percent to 57 percent, depending on growing conditions and seed variety.
The outstanding characteristic of sesame oil is its long shelf life. This quality makes it applicable for use in the manufacture of margarine in many parts of the world where there is inadequate refrigeration. Sesame oil is also used in paints, soaps, cosmetics, perfumes, bath oils, insecticides and pharmaceuticals (vehicle for drug delivery). Poppy seed, cotton seed and rape oils are frequently added to sesame oil.
Sesame seed oil is being investigated as a cell-growth regulator that slows down cell growth and replication, partly through its antioxidant properties. Research shows that the oil can neutralize free oxygen radicals within the skin and surrounding tissues. Other experiments have demonstrated positive effects for helping to clear blocked arteries. The oil quickly permeates and penetrates the skin, entering the blood stream through the capillaries. While in the blood stream, molecules of sesame seed oil maintain good cholesterol (HDL) and assist the body in removing bad cholesterol (LDL).
In addition, sesame oil contains two important antioxidants believed to promote cell integrity and the healthy function of body tissues in the presence of oxidizing compounds: sesamolin and sesamol. These antioxidants maintain fats and increase vitamin E activity dramatically. They are also being researched as potential industrial antioxidants, as well as nutraceuticals and potential templates for synthetic pharmaceutical compounds. In Japan, where sesame seed intake is especially high and a positive sesame product image is well established in the marketplace, sesamin and sesaminol and some related compounds are the focus of considerable laboratory and clinical research.
Pharmaceutical and Neutraceutical Applications
Sesame seed oil has been used as a healing oil for thousands of years. It is naturally antibacterial and effective against common skin pathogens as well as common skin fungi including the athlete's foot fungus. It is naturally antiviral and is a natural anti-inflammatory agent.
Many “natural” cosmetics now include sesame oil because of its antioxidant properties. It has been used in topical preparations in the traditional medicines of India, North Africa and East Asia. It was even used in the early North American colonies. Sesame is an important niche market ingredient In massage oil formulations.
A current pharmaceutical use for sesame oil in the United States is as a “medical carrier” for injected drug or intravenous drip solutions. It also is used as a carrier or as part of a carrier formulation by the cosmetics industry. The oil for pharmaceutical use is extracted from high-quality seed and is more refined than oil intended for human consumption or other “food-grade” (cosmetic) applications.
Ayurvedic medicine has used sesame oil to help treat teen acne and control eruptions, as well as keep the skin soft and supple and tighten facial skin, particularly around the nose, and has been used to help heal minor abrasions. In many traditional Mideast societies, it also is used to protect children against common skin pathogens easily transmitted from animals, for example, ringworm fungus, and is successfully used in the hair of children to treat lice infestations. In some Asian and Middle Eastern countries, the oil is used to treat diaper rash by neutralizing the acidity of urine and lessening the chafing of cloth diapers. In these areas, school-age children have sesame oil swabbed into their noses to protect against air-born viruses and bacteria. As nose drops, sniffed back into the sinuses, sesame seed oil has been used for decades to cure chronic sinusitis.
Sesame Meal and Flour
When the seeds from food-grade, high-oil sesame are processed, the resulting sesame meal contains from 50 percent to 55 percent protein. This meal is often blended with other flours for baking and other food uses. The sesame meal remaining after the oil is pressed from less desirable food-grade or non-food-grade seed is an excellent high-protein feed for poultry and livestock.
Sesame meal and flour are emerging markets with significant growth potential. Both can be added to recipes to give a better nutritional balance to health food products. The antioxidants naturally found in sesame increase the shelf life of other food products produced with the flour.
Increasingly, sesame seed is produced to sell to landowners and government agencies for wildlife food plots. The seed is used to attract and feed game birds. Farmers plant sesame on ditch banks and along wooded creeks to sustain quail and pheasants. In South Carolina, farmers plant sesame for dove hunting.
In the United States, sesame seed production has been limited to the Southwest, primarily due to the lack of mechanically harvestable cultivars suited to other climates. Almost all commercial production is in Texas and Oklahoma. In 2007, sesame was grown on 29 farms. Of those farms, 25 were in Texas and the remaining four were in Oklahoma. All together, U.S. sesame farms produced over 2.9 million pounds of sesame, on about 4,978 acres. (In contrast, less than 2,500 acres were planted to sesame in 1987.) The pounds of sesame have doubled since 2002, with the addition of only seven farms. Most U.S. sesame is grown on contract. (2007 Census of Ag 2009)
In 2010, Sesaco had more than 100,000 acres of sesame under contract production with growers in southwest Kansas, Oklahoma and central Texas.
There are a few factors to consider when deciding to grow this crop. One factor is environmental suitability since the sesame plant grows best in areas where cotton does well. Two other factors important to growers are branching and "shattering resistance." New varieties of sesame allow the plant to dry standing in the field like wheat, corn or soybeans. It can be harvested with standard combines, and cleaned and stored with standard grain-handling equipment. Two final factors that require consideration: the lack of registered herbicides for chemical weed control and of crop disaster insurance.
Today, the decision to plant sesame is based on the fact that it is a high-value oilseed crop with extensive local and overseas markets. Usually local production depends on whether the seed can be routed into a local processing, oil or seed distribution networks.
The sesame plant is an erect annual (or occasionally a perennial) that grows to a height of 20 to 60 inches, depending on the variety and the growing conditions. Some varieties are highly branched, while others are relatively unbranched. The plant thrives best on well-drained, fertile soils of medium texture and neutral pH but has little tolerance for salt. The plant has an extensive system of feeder roots, making it very drought-tolerant. Growing this plant seems to help condition the soil by improving soil structure.
The sesame plant continues to produce leaves, flowers and capsules as long as the weather permits. At maturity, leaves and stems tend to change from green to yellow to red in color. At this point the leaves begin to fall off the plants and the sesame seed pods split, releasing the seed (hence the phrase, "open sesame"). In commercial varieties, maturity occurs in 90 to 120 frost-free days.
According to the Food and Agriculture Organization (FAO), Myanmar (Burma) was the world's largest producer of sesame in 2009, followed by India and then China (FAOstats 2009). Not surprisingly, nearly 70 percent of the world production is in Asia. Africa grows about 25 percent of the world's sesame, with Sudan, Ethiopia and Uganda being key producers.
Several hundred varieties of sesame plants exist. Non-shattering varieties have been developed to allow mechanical harvesting. In the United States, these varieties are usually planted, and some are far better than others for certain climatic zones. Some non-shattering varieties include Baco, Paloma, UCR3, SW-16 and SW-17. In the United States, sesame does particularly well as a re-plant crop.
Sesame should not be planted before the soil reaches a temperature of about 70°F, roughly one month after the last killing frost. Daytime temperatures of 77°F to 80°F are optimal; below 68°F, growth is reduced, and at 50°F, germination and growth is inhibited.
Sesame can be seeded with a row crop planter equipped with vegetable planter boxes. Populations of 250,000 to 300,000 plants per acre in 18- to 30-inch rows have produced the highest recorded yields. This is about 1 pound per acre for 30-inch rows. Depth of planting varies with soil type and soil moisture from 1 to 2 inches. Uniform depth and seed rate are essential for stand establishment resulting in maximum yield.
Fertility requirements for sesame are 80 pounds of nitrogen, 20 pounds of phosphorus and 20 pounds of potassium per acre. The nitrogen recommendation is for soils with less than 2 percent organic matter. The nitrogen can be reduced to 60 pounds per acre for soils with 2 percent to 5 percent organic matter and to 40 pounds per acre if the soil has more than 5 percent organic matter. The phosphorus and potassium recommendations are for soils testing in the "optimum" range. A soil pH of 5.6 or above is satisfactory.
Sesame requires a warm, moist, weed-free seedbed. Good drainage is important, because the plant is extremely susceptible to waterlogging at any stage of growth. However, the plant also requires adequate moisture for germination and early growth, and a minimum rainfall of 20 to 26 inches per season is necessary for reasonable yields. Moisture levels before planting and flowering have the greatest impact on yield. Light rains during the dry-down period will not seriously damage seed, but the crop should be regularly inspected for the onset of mold or similar fungal problems.
In the United States, these fungal problems tend to be the same as those for grain sorghum and usually are treated on an as-needed basis. A fungicidal seed treatment is especially important for non-shattering varieties, because the planted seeds are slower to emerge than the shattering varieties. Since the seeds for these varieties spend more time in the soil before germination, they need more protection from fungal pathogens.
Sesame plants are poor competitors against weeds. Select fields with low weed densities and cultivate sesame fields early and as close to the rows as possible. Shallow cultivation is recommended, because the fine, fibrous sesame roots grow close to the surface and are easily damaged. Cultivate only as necessary to control weeds.
Given the potential of fall rains in many regions, it is probably best to plan on timely harvest of the crop. Sesame harvest is usually begun about 90 to 150 days after planting. To obtain high-quality seeds, the crop must be harvested before the first killing frost.
Sesame seed is easily threshed. It can be combined using an all-crop reel head or a row crop header, such as a soybean row header. Screens with 1/8 inch round perforations are appropriate for this seed size. Since the seed is small, holes in combines or trucks may need to be sealed with duct tape.
Sesame seed is also relatively delicate. Seed damage during harvesting can affect seed viability, and storage and oil quality. To minimize seed damage and loss, non-shattering types can be combined at low cylinder speed (450-500 rpm) or about half of that required for cereals.
Shattering and non-shattering types of sesame require different harvesting techniques. Mechanical harvesting is more successful with varieties that have minimal branching and a height from the soil surface to the first seed pod of about 12 inches. Late-season rainfall prolongs growth and increases shattering loss. Wind can also cause shattering at harvest.
Since sesame is a small flat seed, it is difficult to move much air through it in a storage bin. Therefore, the seeds need to be harvested as dry as possible and stored at 6 percent moisture or less. If the seed is too moist, it can quickly heat up and become rancid.
After harvesting, the seeds are cleaned and hulled. The seeds pass through an air separation stage to remove any foreign particles. About 10 percent of this "cleaned natural seed" moves directly into food use as whole seed to be blended into flour for baked goods. Next, a combination of water and friction work together as the seeds are passed against the chamber of the hulling machine to separate the hull from the seeds. This dust-free de-hulled seed makes up 30 percent of domestic production and has a 99.97 percent purity for the baked goods market. Once the seeds have been hulled, they are passed through an electronic color-sorting machine that rejects any discolored seeds to ensure perfectly colored sesame seeds. Immature or off-sized seed is removed but saved for oil production.
Sesame oil is extracted by pressure in a mechanical expeller and is tolerant of only minimal heating by the extraction process. This pure, mechanically expressed oil is called “virgin” oil and is preferred by many food handlers. The oil is often blended with other vegetable oils for salads and other food uses. Sesame oil should be kept refrigerated. Sesame seeds can become rancid if exposed to prolonged heat. If properly stored, the packed seeds have a 2-year shelf life with little reduction in quality.
Markets and Economics
Sesame yields in test plots average 1,000 to 1,500 pounds per acre, though as much as 2,300 pounds per acre have been produced on irrigated fields. Commercial yields are usually lower. The introduction of the non-shattering characteristic into high-yielding, shattering varieties carried with it a reduction in yield and/or seed quality.
Sesame benefits from both a high price and a strong domestic market, with organic sesame commanding a significantly higher price. This high price, roughly double that of sunflowers or soybeans, is offset by the relatively low yields of sesame.
For Western producers, production costs are modest, being equal to or less than soybeans or sorghum. Seed costs are similar to conventional crops. The cost savings from not using herbicides (none are labeled for sesame) is partially offset by extra tillage for weed control. Fertilizer costs are primarily for nitrogen, which can be met through organic sources. Harvest costs should be similar to other grains, but transportation to market will be an extra expense since delivery points for this specialty crop may be a considerable distance from the grower.
Most farmers growing sesame under contract in the United States are working with the Sesaco Corporation, a private company based in Paris, Texas. Sesaco provides their own varieties (available only to contract producers) and does the processing and marketing of the seed and oil. Producers potentially can market their sesame directly to food brokers or processors but may have trouble obtaining high-quality varieties to plant, since Sesaco is the only group actively developing and distributing seed in the United States. Independent food brokers may be unwilling to contract for sesame in advance of planting, and planting sesame without a contract is risky for growers.
The only two sesame buyers in the United States are Sesaco and Arrowhead Mills, Hereford, Texas (organic only).
Plant breeders have demonstrated that the antioxidant content in sesame may be enhanced through traditional crop-breeding techniques. Sesame breeding programs in the United States, Korea, China, Thailand and Japan now consider the antioxidant level as a primary selection factor in the development of future varieties.
Export and Import
International demand for sesame continues to increase every year. The world's traded sesame seed recently surpassed one million tons per year and was valued at roughly $850 million. In the last 15 years, world trade in sesame has increased by nearly 80 percent.
The United States imports more sesame than it grows. in 2010, the United States imported sesame seed valued at $69.9 million, relatively unchanged form 2009. Nearly 60 percent of the sesame was from India, followed by Guatemala. The seed is mainly used for baked and other food products, although non-food cosmetic applications are increasing.
The United States did export both sesame seed and sesame oil in 2010. Sesame seed valued at more than $6.1 million, a 98 percent jump from 2009, was exported, mainly to Japan. The value of exported sesame oil also grew, by 21 percent, to $2.8 million. Canada was the largest buyer, followed by Netherlands, Turkey and France.
Japan is the world’s largest importer of sesame seed. Sesame oil, particularly from roasted seed, is an important component of Japanese cooking and traditionally this is the principal use of the seed. China is the second largest importer of sesame, mostly oil-grade sesame. (The country exports food-grade sesame.)
To ensure a top price for the commodity and enhance the market share through exports, particularly in Asia, product image (quality perception) is important. Most importers who supply ingredient distributors and oil processors only want to purchase scientifically treated, properly cleaned, washed, dried, color-sorted, size-graded and impurity-free seeds of given minimum oil content (not less than 40 percent) packed according to international standards. Usually, only seed meeting these criteria may be exported from a producing country.
2007 Census of Ag, National Ag Statistical Service (NASS), USDA, 2009.
Agricultural Statistics 2009, NASS, USDA.
FAOstats, UN, 2009.
Global Agricultural Trade System, Foreign Agricultural Service, USDA.
Sesame - A New Summer Crop, DTN Progressive Farmer, 2010.
Prepared February 2005 and reviewed August 2011.