Sesame

Revised April 2022

Introduction

Sesame (Sesamum indicum L.) is likely one of the oldest cultivated plants in the world that is grown for edible oil. Evidence of early sesame production has been found dating back to 1600 B.C from the Tigris and Euphrates valleys. Many wild relatives of sesame are found in sub-Saharan Africa, with somewhat fewer also found in India. Sesame was widely adopted as an early crop because it had the ability to grow in areas where other crops couldn’t, particularly under hot and dry conditions. For this reason, it has been called a ‘survivor’ crop. Currently, sesame is grown widely in the warmer regions of the world, with the largest production occurring in Sudan, India, Myanmar and Tanzania. In many countries it is quite often grown as a minor crop in the farm and is used to add flavor and variety to local dishes rather than as a primary source of cooking oil. Furthermore, in many regions the cultivars used are highly susceptible to shattering upon maturity, so the harvest process is labor intensive in order to reduce these losses.

Sesame was introduced into the U.S. in the 1930’s, though historical documentation indicates 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. The first U.S. commercial production began in the 1950s following the discovery of a non-shattering mutation in 1943 that allowed breeding and development of varieties suitable for machine harvest.

Production

In the United States, sesame seed production has been limited to the south, primarily due to the lack of suitable cultivars adapted to other climates and the lack of nearby markets. Almost all commercial production is in Texas and Oklahoma, with limited acreage in Kansas and Florida reported in the 2017 Census of Agriculture. The U.S. produced 31 million pounds of sesame in 2017. Imports of sesame into the U.S. were about twice that amount.

The sesame plant is an erect annual 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 a sesame crop can help condition the soil by improving soil structure.

This warm-season, annual, crop of the semiarid tropics and subtropics requires a relatively long growing season with hot conditions to produce maximum yields. More specifically it requires 110-150 frost-free days, warm soils, not less than 70 o F for seed germination and average daily temperatures that range from 86 to 92o F for best growth and seed set. It has been grown as far north as 40o N latitude in the U.S., but due to growing degree requirements, production in these more northern zones can be risky and yields marginal.

Sesame is drought tolerant and does not require irrigation, though studies have been conducted under irrigation that demonstrated yield increases with irrigation.  It is generally planted in rows, rather than drilled.

All commercially produced cultivars of sesame are non-shattering types, though they still may exhibit some level of seed loss prior to or during harvesting. 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.

Combine harvest requires special care, as sesame seed is relatively delicate and easily damaged during harvesting. This damage can affect seed viability and oil quality. In addition, broken seeds reduce the crop grade. 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.  
After harvest, seed should be further cleaned using standard seed cleaning equipment.

Because sesame is a small flat seed, it is difficult to aerate it in a storage bin, so 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 and the oil become rancid.

Processingbottle of golden oil by spilled bag of small white seeds

After harvesting, the seeds are cleaned and/or dehulled. 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 or placed on the top of 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. Once the seeds have been dehulled, 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 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.
 
Sesame oil is extracted by pressure in a mechanical expeller and is tolerant of only minimal heating by the extraction process. The oil is often blended with other vegetable oils for salads and other food uses. Sesame oil should be kept refrigerated.

Marketing

Most farmers grow sesame under contract in the United States. Sesaco Corporation, a private company based in Paris, Texas, has been the major buyer of sesame in the U.S. 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 has traditionally been the major plant breeding program working with sesame in the U.S. There are other companies that have an interest in the sesame market that may have or soon will have varieties that are adapted to the U.S.

Sesame Seeds
Sesame seeds contain 50-55 percent oil and 25 percent protein. The oil contains approximately 47 percent oleic acid and 39 percent linoleic acid.  Sesame seeds are used in baking, to top breads, buns and bagels, in crackers and in cakes. The ground seeds are used in East African cuisine in soups and fish dishes. They are also used in sweets, including a product similar to peanut brittle. Ground seeds are also used as a condiment in some Asian and Indian dishes.

Tahini, a traditional Mideast sesame paste 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.

Sesame Oil
Commercially, sesame oil comes in two 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 a 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 due to the antioxidant, sesamol. 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.

Sesame Meal and Flour
When the seeds from food-grade, high-oil sesame are extracted, the resulting sesame meal contains from 34 to 50 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.

Both sesame meal and flour 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.

Pharmaceutical and Nutraceutical 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.

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.

Financial

The national average yield for sesame was 572 lb per acre based on 2017 census data. However, sesame yields in test plots commonly average between 1,000 to 1,500 pounds per acre and yields as high as 2,300 pounds per acre have been achieved with irrigation. Sesame production is usually contracted as the market is quite specialized. Contract prices may vary based on the supplies available internationally as well as demand both locally and internationally. Organic sesame will always provide a premium.

Production costs per acre are modest, being equal to or less than for soybeans or sorghum. 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. Harvest costs are 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.

Sources

Production Guides