**4. Harvesting and post harvesting handling of sesame seed**

Sesame seed is harvested when about 50% of capsules turn yellow in colour from green. Other indications of the optimum time for harvesting (physiological ripeness) include; lowest capsules turning brown and beginning to pop open, stem turning yellow, leaves beginning to fall off, end of blossoming, leaves turning yellow (Kimbonguila et al., 2009). Harvesting should not be delayed in order to prevent seed loss through shattering. The size and shape of sesame seed (ie small and flat) makes it 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 (Hansen, 2011, Nigeria's Harvest, 2009; Langham et al., 2008). If the seed is too moist, it can quickly heat up and become rancid. High levels of humidity can cause sesame to take on moisture again and go mouldy; it should therefore only be stored

Sesame Seed 89

Sesame seed (*Sesamum indicum* L.), from Northern Congo were reported to contain 5.7% moisture, 48.5% crude oil, 20% crude proteins, 7.78% carbohydrate (by difference), 9.4% crude fiber and 4.2% ash (Nzikou et al., 2009; 2010). The protein content of White Sudan sesame seed was high (~25%) similar to other foodstuffs rich in proteins such as almond, hazelnut protein the contents of which were respectively, 20% and 21% (Borchani et al., 2010). The ash content in raw sesame was relatively high (~5%) compared to other products of great consumption such as almond (3%), and the pistachio (2.7%) (Borchani et al., 2010). Other Sudanese local and improved varieties considered by El Khier et al (2008) had protein

The seeds also contained significant amount of important minerals with the Potassium concentration being the highest, followed by Phosphorus, Magnesium, Calcium and Sodium (Loumouamou et al., 2010). For White sesame seed (*S. indicum* L.) from Sudan, oil was 52.24%, protein 25.97%, fibre 19.33% and ash 4.685 (El Khier et al, 2008). The predominant mineral composition was calcium followed by potassium, magnesium and phosphorus. All other elements were present in comparatively low concentrations (Elleuch et al., 2007). This is similar to the results obtained by Borchani et al. (2010) for white Sudanese sesame. Potassium is an essential nutrient and has an important role is the synthesis of amino acids and proteins. Calcium and Magnesium plays a significant role in photosynthesis, carbohydrate metabolism, nucleic acids and binding agents of cell walls. Calcium assists in teeth development Magnesium is essential mineral for enzyme activity, like calcium and chloride; magnesium also plays a role in regulating the acid-alkaline balance in the body. Phosphorus is needed for bone growth, kidney function and cell growth. It also plays a role in maintaining the body's acid-alkaline balance. The presence of these minerals also

confirms the fat that sesame seed is of high nutritional benefit to its consumers.

The seed characteristics or physical properties of sesame seeds vary and this variation may likely be as a result of variability in genotypic effects (El Khier et al., 2008). The physical properties i.e length, width, thickness, geometric mean diameter, sphericity and surface area of the two common local sesame seeds varieties in Nigeria varied from 2..9 – 3.2mm, 1.9 – 2.1mm, 0.85 – 0.91mm, 1.59 – 1.72mm, 0.575 – 0.58 and 7.05 - 10.2mm2 respectively (Tunde-Akintunde and Akintunde, 2007). The values obtained for the local varieties were close to that obtained for improved varieties obtained at the National Centre for Genetic Resources and Biotechnology (NACGRAB), Moor plantation, Ibadan, Oyo State, Nigeria which include NCRI BEN 0IM, NGB\04\026, NCRI BEN 03L, NG\SA\07\179, NG\SA\07\090, NG\SA\07\095, NG\SA\07\106, NG\SA\07\052, NG\SA\07\137, OM1, OKENE MKT, NCRI BEN 02M, KANO 05. The length of the improved varieties varied from 2.26mm – 3.01mm, width 1.55 – 1.86mm, thickness 0.74 – 0.97mm and the geometric mean diameter varied from 1.32 – 1.7mm. The variation in degree of sphericity and that of surface area was from 0.57 – 0.64 and 5.84 – 8.94 mm2 respectively (Adebowale et al., 2010). The length, width, and thickness of a local sesame seed variety Giza 32 from the Agricultural Engineering Research Institute, Egypt was 2.5, 1.65, and 0.94 mm respectively while the geometric diameter, sphericity and flat surface area were 1.57 mm, 62.84 % and 3.24 mm2

**6. Description / Physical properties of sesame seed** 

respectively (Arafa, 2007).

content of 32.50 to 35.94 and 33.43 to 40.00 respectively.

for a short while, or in air-tight containers. If the critical 6% cannot be reached by using only sun drying then artificial methods must be employed. This is because sesame above 5.1% starts getting docked for moisture weight, and above 6.9% moisture, there are quality discounts.

Sesame is generally harvested manually by cutting stems with sticks, and then left to dry for the first 2-3 days after cutting in a windrow (Naturland, 2002). The leaves dry out quickly there, making it easier to bundle them into sheaves. Plants are tied with a rope into small bundles or sheaves (diameter of 15 cm, bottom: 45-80 cm) and positioned erect on a mat or tarpaulin for drying to complete. This prevents seed wastage ns contamination. The sheaves should be positioned so that the sun can shine down directly onto the capsules. This results in less drying time, better heat and air circulation, avoidance of fungi infection, ease of turning when shaking bundles, more extensive shaking/threshing with fewer losses. The sheaves should not need to be dried for longer than 15 days. After the sheaves have dried out fully, they are tipped out onto sturdy cloths or canvases and threshed with sticks. The cloths/canvases should be at least 6 m², to avoid contamination with stones and soil.

Mechanical harvest is better, as the unripe plants are cut, and then the pre-dried sheaves threshed out. This reduces the amount of seeds lost, and the hay makes better fodder. Most threshing machines with a sheaf pick-up function are suited to the task. Varieties that open are easier to thresh mechanically than those that remain closed, as less force is needed. . Sesame seed is easily threshed and relatively delicate, so drum speed should be reduced to about half of that required for cereals, and the concave clearance made as wide as possible. Seed damage during harvesting affects both the viability of the seed, storage and the quality of the oil.

After the seeds have been harvested and dried, the storage sacks must be checked and free of insects. Packaged sesame should be stored in a dark place at low temperatures (below 18°C) and low relative humidity. Also sesame contain more of unsaturated fats hence should be stored in air-tight containers to avoid them turning rancid. Under optimum storage conditions, sesame can be stored for several months even up to 1 year. For safe longterm storage, sesame seed should be clean, have moisture content no more than 6% and be stored at a relative humidity of approximately 50% and at a temperature less than 18°C (Bennet, 2011).

#### **5. Nutritional benefits of sesame seed**

Sesame seed (*Sesamum indicum L*.) is an oilseed with a chemical composition of about 50-52% oil, 17-19% protein and 16-18% carbohydrate (Tunde-Akintunde and Akintunde, 2004). Its seed contains about 42-54 % quality oil, 22-25 % protein, 20-25 % carbohydrates and 4-6% ash. The hull contains large quantities of oxalic acid, crude fiber, calcium and other minerals. When the seed is properly dehulled, the oxalic acid content is reduced from about 3 % to less than 0.25 % of the seed weight (Akinoso et al., 2010). Sesame seed contains antioxidants which inhibit the development of rancidity in the oil. In the food industry, where synthetic antioxidants are used extensively, there is an increasing demand for more of these natural products (Bennet, 2011). The nutritional benefits derived from sesame seeds are based on the variety being utilized.

for a short while, or in air-tight containers. If the critical 6% cannot be reached by using only sun drying then artificial methods must be employed. This is because sesame above 5.1% starts getting docked for moisture weight, and above 6.9% moisture, there are quality

Sesame is generally harvested manually by cutting stems with sticks, and then left to dry for the first 2-3 days after cutting in a windrow (Naturland, 2002). The leaves dry out quickly there, making it easier to bundle them into sheaves. Plants are tied with a rope into small bundles or sheaves (diameter of 15 cm, bottom: 45-80 cm) and positioned erect on a mat or tarpaulin for drying to complete. This prevents seed wastage ns contamination. The sheaves should be positioned so that the sun can shine down directly onto the capsules. This results in less drying time, better heat and air circulation, avoidance of fungi infection, ease of turning when shaking bundles, more extensive shaking/threshing with fewer losses. The sheaves should not need to be dried for longer than 15 days. After the sheaves have dried out fully, they are tipped out onto sturdy cloths or canvases and threshed with sticks. The

cloths/canvases should be at least 6 m², to avoid contamination with stones and soil.

Mechanical harvest is better, as the unripe plants are cut, and then the pre-dried sheaves threshed out. This reduces the amount of seeds lost, and the hay makes better fodder. Most threshing machines with a sheaf pick-up function are suited to the task. Varieties that open are easier to thresh mechanically than those that remain closed, as less force is needed. . Sesame seed is easily threshed and relatively delicate, so drum speed should be reduced to about half of that required for cereals, and the concave clearance made as wide as possible. Seed damage during harvesting affects both the viability of the seed, storage and the quality

After the seeds have been harvested and dried, the storage sacks must be checked and free of insects. Packaged sesame should be stored in a dark place at low temperatures (below 18°C) and low relative humidity. Also sesame contain more of unsaturated fats hence should be stored in air-tight containers to avoid them turning rancid. Under optimum storage conditions, sesame can be stored for several months even up to 1 year. For safe longterm storage, sesame seed should be clean, have moisture content no more than 6% and be stored at a relative humidity of approximately 50% and at a temperature less than 18°C

Sesame seed (*Sesamum indicum L*.) is an oilseed with a chemical composition of about 50-52% oil, 17-19% protein and 16-18% carbohydrate (Tunde-Akintunde and Akintunde, 2004). Its seed contains about 42-54 % quality oil, 22-25 % protein, 20-25 % carbohydrates and 4-6% ash. The hull contains large quantities of oxalic acid, crude fiber, calcium and other minerals. When the seed is properly dehulled, the oxalic acid content is reduced from about 3 % to less than 0.25 % of the seed weight (Akinoso et al., 2010). Sesame seed contains antioxidants which inhibit the development of rancidity in the oil. In the food industry, where synthetic antioxidants are used extensively, there is an increasing demand for more of these natural products (Bennet, 2011). The nutritional benefits derived from sesame seeds

discounts.

of the oil.

(Bennet, 2011).

**5. Nutritional benefits of sesame seed** 

are based on the variety being utilized.

Sesame seed (*Sesamum indicum* L.), from Northern Congo were reported to contain 5.7% moisture, 48.5% crude oil, 20% crude proteins, 7.78% carbohydrate (by difference), 9.4% crude fiber and 4.2% ash (Nzikou et al., 2009; 2010). The protein content of White Sudan sesame seed was high (~25%) similar to other foodstuffs rich in proteins such as almond, hazelnut protein the contents of which were respectively, 20% and 21% (Borchani et al., 2010). The ash content in raw sesame was relatively high (~5%) compared to other products of great consumption such as almond (3%), and the pistachio (2.7%) (Borchani et al., 2010). Other Sudanese local and improved varieties considered by El Khier et al (2008) had protein content of 32.50 to 35.94 and 33.43 to 40.00 respectively.

The seeds also contained significant amount of important minerals with the Potassium concentration being the highest, followed by Phosphorus, Magnesium, Calcium and Sodium (Loumouamou et al., 2010). For White sesame seed (*S. indicum* L.) from Sudan, oil was 52.24%, protein 25.97%, fibre 19.33% and ash 4.685 (El Khier et al, 2008). The predominant mineral composition was calcium followed by potassium, magnesium and phosphorus. All other elements were present in comparatively low concentrations (Elleuch et al., 2007). This is similar to the results obtained by Borchani et al. (2010) for white Sudanese sesame. Potassium is an essential nutrient and has an important role is the synthesis of amino acids and proteins. Calcium and Magnesium plays a significant role in photosynthesis, carbohydrate metabolism, nucleic acids and binding agents of cell walls. Calcium assists in teeth development Magnesium is essential mineral for enzyme activity, like calcium and chloride; magnesium also plays a role in regulating the acid-alkaline balance in the body. Phosphorus is needed for bone growth, kidney function and cell growth. It also plays a role in maintaining the body's acid-alkaline balance. The presence of these minerals also confirms the fat that sesame seed is of high nutritional benefit to its consumers.

#### **6. Description / Physical properties of sesame seed**

The seed characteristics or physical properties of sesame seeds vary and this variation may likely be as a result of variability in genotypic effects (El Khier et al., 2008). The physical properties i.e length, width, thickness, geometric mean diameter, sphericity and surface area of the two common local sesame seeds varieties in Nigeria varied from 2..9 – 3.2mm, 1.9 – 2.1mm, 0.85 – 0.91mm, 1.59 – 1.72mm, 0.575 – 0.58 and 7.05 - 10.2mm2 respectively (Tunde-Akintunde and Akintunde, 2007). The values obtained for the local varieties were close to that obtained for improved varieties obtained at the National Centre for Genetic Resources and Biotechnology (NACGRAB), Moor plantation, Ibadan, Oyo State, Nigeria which include NCRI BEN 0IM, NGB\04\026, NCRI BEN 03L, NG\SA\07\179, NG\SA\07\090, NG\SA\07\095, NG\SA\07\106, NG\SA\07\052, NG\SA\07\137, OM1, OKENE MKT, NCRI BEN 02M, KANO 05. The length of the improved varieties varied from 2.26mm – 3.01mm, width 1.55 – 1.86mm, thickness 0.74 – 0.97mm and the geometric mean diameter varied from 1.32 – 1.7mm. The variation in degree of sphericity and that of surface area was from 0.57 – 0.64 and 5.84 – 8.94 mm2 respectively (Adebowale et al., 2010). The length, width, and thickness of a local sesame seed variety Giza 32 from the Agricultural Engineering Research Institute, Egypt was 2.5, 1.65, and 0.94 mm respectively while the geometric diameter, sphericity and flat surface area were 1.57 mm, 62.84 % and 3.24 mm2 respectively (Arafa, 2007).

Sesame Seed 91

seeds, which is used as an ingredient (in Greece) and halva, placed within breads or sprinkled on the surface of bread and breadsticks as a garnish (Germany and the Netherlands) and for the preparation of rolls, crackers, cakes and pastry products in commercial bakeries (Nzikou et al., 2009). Ground and processed seeds can also be used in sweet confections, candies are made from sesame mixed with honey or syrup and roasted (in South Asia, middle East and East Asia) while sesame paste and starch are used to make *goma-dofu* (Japan). Sesame seed can also be in the manufacture of margarine, sprinkled over salads and desserts, particularly sundaes and other ice cream based preparations, preparation of gomshino (a Japanese delicacy) and soybean oil. It can also be used in other

Sesame seed is primarily grown for its oil in Nigeria and the oil is a primary source of cooking oil in Eastern Nigeria. The major portion of sesame seed produced in countries like Nigeria and India is used for extraction of oil. Sesame oil is mostly used as traditional cooking oil in Chinese food items and in Japan. Sesame seed is an excellent source of high quality oil and protein, its oil is odourless and close in quality to olive oil (Tunde-Akintunde and Akintunde, 2007). Sesame oil has no odour, it is straw-like in colour and has an excellent taste. Sesame seed oil is a natural salad oil, requiring little or no winterization, is one of the few vegetable oils that can be used directly without refining and is used widely as cooking oil. Because of the excellent quality of the edible oil it produces, sesame is often called queen of the oil seed crops. Light sesame oil have a high smoke point and is suitable for deep-frying, while dark sesame oil (from roasted sesame seeds) has a slightly lower smoke point and is unsuitable for deepfrying. Instead it can be used for the stir frying of meats or vegetables, or for the making of an omelette. East Asian cuisines often use roasted sesame oil for seasoning. It is also used widely for production of magarine, shortening, canned sardine and beef as well as in soap and confectionary industries (NAERLS, 2010). Sesame oil has a high preservative effect though the seeds are prone to rancidity because of its high oil content. The oil prevents rancidity due to a preservative within the oil called sesamol. Sesame oil obtained during the first, cold pressing is one of the costliest produced. The oil is light yellow, does not dry out, and can be used with strong heat. Sesame oil obtained from the second, warm pressing and extraction has a lower

In the industry, sesame oil may be used as a solvent in injected drugs or intravenous drip solutions, a cosmetics carrier oil, to coat stored grains to prevent weevil attacks. The oil also has synergy with some insecticides. Lower grade sesame oil can be used locally in soaps, lubricants, and illuminants. Sesame oil can also be used as a raw material in the manufacture of inks (sesame oil yields a top quality ink after it is burnt), paints, and pharmaceuticals (as healing oil or a vehicle for drug delivery). The oil also has additional use in the industrial preparation of perfumery, cosmetics (skin conditioning agents and moisturizers, hair preparations, bath oils, hand products and make-up), insecticides and paints and varnishes. However, all of these uses are comparatively insignificant in terms of

The seed is typically crushed intact for the oil. This, however, yields a meal that is made bitter and somewhat indigestible by the presence of the fibrous husk. As such the meal is only useful as cattle feed. The quality of the meal can however be improved by removing the seed coat, dehulling, before crushing. In India, where sesame meal is an important food, this process is a standard feature of an oil extraction plant. The meal remaining after oil extraction has unique nutritional properties. It has a high protein concentration which is rich

food dishes including Mexican and East Asian cuisines.

quality than cold-pressed.

the quantities used.
