Sesame Profile

By Ray Hansen, content specialist, AgMRC, Iowa State University, hansenr@iastate.edu.

Revised August 2011 by Diane Huntrods, AgMRC, Iowa State University.

Revised July, 2016 by Margaret Smith, AgMRC, Iowa State Unviersity

Introduction

Sesame (Sesamum indicum L.), is likely one of the oldest cultivated plants in the world grown for edible oil. Production records have been found dating back to 1600 B.C from the Tigris and Euphrates valleys. Many wild relatives are found in sub-Saharan Africa, with somewhat fewer also found in 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 udner hot and dry conditions. It been called a ‘survivor’ crop.

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.

In 2014, India was the largest producer of sesame seed followed closely by Sudan. China was third in production, followed by Myanmar and Tanzania. Nearly 55 percent of the world sesame production is in Africa and 42 percent is in Asia. (FAO)

Marketing

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. Arrowhead Mills, Hereford, Texas also contracts with growers for organic sesame. (need to check this for Arrowhead Mills)

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, fish dishes. They are also used in sweets, including a dish similar to peanut brittle. Ground seeds are also used as a condiment in some Asian and Indian dishes.

Sesame oil is used in salad and cooking oils, shortening and some margarines. It is a key flavor ingredient in some Chinese dishes.. Sesame oil keeps well and resists rancidity, due to the presence of an antioxidant, sesamol.

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.

Non-food uses for sesame oil include ingredients in soaps, paints, cosmetics, perfumes and insecticides

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 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 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.

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.

Production

In the United States, sesame seed production has been limited to the south, primarily due to the lack of mechanically harvestable cultivars suited to other climates. Almost all commercial production is in Texas and Oklahoma, but production is spreading to Kansas and Arkansas In 2010, Sesaco had more than 100,000 acres of sesame under contract production with growers in southwest Kansas, Oklahoma and central Texas. The USDA did not survey sesame production in the 2012 Census of Agriculture.

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 this plant seems to help condition the soil by improving soil structure.

This warm-season, annual, rainfed crop of the semiarid tropics and subtropics requires five frost-free months for production and needs hot conditions to produce maximum yields. It can, however, be grown up to 40o N in the U.S. Sesame grown in the U.S is produced largely in Texas.

Requirements for production include 110-150 frost-free days, warm soils, not less than 70 o F for seed germination and average daily temperatures from 86 to 92o F for best growth and seed set. Sesame is drought tolerant and does not require irrigation, though studies have been conducted under irrigation that demonstrated yield increases.  It is generally planted in rows, rather than drilled.

Texas A. & M. University provides an excellent Sesame Production Guide as does Sesaco, with their 2012 Sesame Producers Guide.

Management

Harvesting

Combine harvest requires special care, Sesame seed is relatively delicate and easily damaged during harvesting. This damage can affect seed viability and oil quality. In addition, broken seed reduces 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.  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.

After harvest, seed should be further cleaned using standard seed cleaning equipment.

Storage

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.

Processing

After harvesting, the seeds must be cleaned and 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 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. 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. 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.

Financial

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.

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, which can be met through organic sources. 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. Arkansas growers report production costs (excluding land) of $70 to $80.A.

Sources