Durum Wheat Products
Semolina, durum granular, and durum flour milled from durum wheat are used to manufacture paste and non-paste food products. Paste products are manufactured by mixing water with semolina or durum flour to form unleavened dough, which is formed into different shapes and either cooked and eaten or dried for later consumption. Pasta and couscous are paste products. Products of durum wheat in a high moisture leavened or unleavened bread and cooked or steamed bulgur (cracked durum wheat) and frekeh (parched immature wheat kernel) are non-paste food products.
Paste products are the most ancient source of food consumed from wheat. Pasta has been produced in the Mediterranean region since antiquity. The Etruscans, who lived in Italy from the ninth to the fourth century B.C., are thought to have produced a lasagna-like product. Popularity of pasta increased with time. In the early Middle Ages, Palermo was a major center of pasta production. By the end of the Middle Ages, pasta makers were so numerous that their associations were regulated by strict rules. In the 1800s, Naples was the major center of pasta production. The first mechanical pasta press was invented in the 1800s. In 1933, the first continuous pasta press was invented. Today, pasta presses are capable of producing 3,500 kg h-1 spaghetti and up to 8,000 kg h-1 macaroni. Italians categorize pasta into four main groups: long goods (spaghetti, vermicelli, and linguine), short goods (elbow macaroni, rigatoni, and ziti), egg noodles (pasta made with eggs), and specialty items (lasagna, manicotti, jumbo shells, and stuffed pasta. Italian extruded food and Oriental noodles differ. Pasta noodles are made from durum or non-durum wheat with a minimum requirement of 5.5% egg solids. Oriental noodles are made from non-durum wheat flour.
In the Western Hemisphere and Europe, macaroni products are usually referred to as alimentary pastes. Macaroni (hollow tubes), spaghetti (solid rods), noodles (strips, either flat or oval), and shapes (stamped in various forms from sheets of dough) are known as the macaroni products. The Eastern world rarely consumes macaroni products.
Several reviews on pasta processing are available in the literature. Typically, semolina and other ingredients are mixed together in a premixer. The semolina mixture is conveyed to a mixer, which is under vacuum. Once in the mixer, the semolina mixture is hydrated to 28% to 32% with warm water. Paddles in the mixer continuously agitate the wetted semolina mixture while moving the hydrated mixture toward the extrusion auger. The retention time in the mixer is adjusted to allow full hydration of the semolina before it enters the extrusion auger. Full hydration of the semolina particles is very important for the development of the protein (gluten) matrix during pasta extrusion. Development of the protein matrix does not occur during mixing, since the energy supplied by the mixer is insufficient to develop the protein matrix.
Dough develops as it moves along the extrusion auger, which kneads the hydrated semolina and exerts pressure on the dough as it progresses through the extrusion barrel toward the die. The back pressure in the extrusion barrel helps to produce a dense product where starch granules are deeply embedded within the protein matrix. The extrusion process occurs under vacuum. Extruding under vacuum is important in dried pasta, as air trapped in pasta will expand during drying particularly during high and ultrahigh temperature drying. These expanded air pockets are points of weakness and detract from the desired uniform, translucent, yellow color. Removing air also reduces pigment loss catalyzed by the enzyme, lipoxygenase. Fresh or frozen pasta manufacturers generally do not use a vacuum system during the extrusion process. The air bubbles in the product do not seem to have any significant impact on the end product appearance or cooking quality.
Couscous, a paste product made from mixing semolina with water, is considered one of the major food staples in North African countries, such as Egypt, Libya, Tunisia, Algeria, and Morocco. An estimated 10% of durum wheat in the Near East is used to manufacture couscous. While couscous is usually made from durum wheat semolina in North African countries, it is also made from bread wheat, sorghum, pearl millet, or maize in other regions of the world.
Sticky cooked couscous is extremely undesirable. Stickiness has been positively correlated with starch damage and long rehydration time for weak gluten cultivars.
Traditionally, couscous is handmade in small quantities in the home by mixing a small quantity of water with semolina in a large bowl. The moisture content of the hydrated semolina is ~30%. The hydrated semolina is rubbed between the hands until small granules are formed. These granules are screened through sieves to obtain a uniform size. Granule size uniformity is very important for good cooking quality. Hydration rate during cooking will be slower with larger than with smaller couscous granules. The granules are precooked, dried in the sun, and stored.
Commercially, couscous can be produced continuously at 500 kg h-1. The steps required to make commercial couscous are the same as traditional couscous. Manufacturing couscous requires eight steps: 1) Blending: Semolina is mixed with water or a salt water; 2) Agglomeration: Semolina particles are combined into a mixture; 3) Shaping: The particulate mixture is reduced and shaped; 4) Steaming: The resulting granulate is precooked; 5) Drying: The coarse agglomerates are dried; 6) Cooling: The products are cooled to ambient temperature; 7) Grading: The couscous is separated into fine (0.8 to 1.2 mm), medium, and coarse (1.5 to 2.5 mm) granules; and 8) Storage: The couscous is stored until packaged.
Couscous is steam cooked so nutrients are not leached out. Couscous swells upon steaming, and additional swelling occurs when sauce is added. Good-quality couscous requires good cooked flavor and mouthfeel. Good-quality couscous should not be sticky, but should absorb sauce well, have uniform particle size, and have individual particles that maintain their integrity during steaming and sauce application. All these factors affect the taste and mouthfeel of couscous. Stickiness and mouthfeel are the most important textural determinants of quality.
Couscous, a versatile food in North Africa, is served in many different ways and with a variety of foods. Couscous is often steamed and served with meat or vegetables.
Bulgur, a non-paste parboiled durum wheat product, is one of the oldest cereal-based foods. Bulgur is used as a main dish or as one of the ingredients in most food consumed in Turkey, Syria, Jordan, Lebanon, and Egypt. Bulgur can be made from bread wheat, durum, barley, and maize. However, durum is preferred because of its hardness and amber color. An estimated 15% of durum wheat in the Near East is used to make bulgur.
In the Middle East, Turkey, Greece, and Cyprus, bulgur made at home or commercially follows the same steps with one exception: both hard red wheat and durum wheat are used for commercial bulgur; only durum wheat is used for homemade bulgur.
Bulgur making involves three steps: 1) The wheat is cleaned, soaked in water, and cooked to gelatinize the starch. 2) The cooked grain is cooled, dried, moistened, peeled to remove the bran (optional), redried, and cleaned by winnowing. 3) The grain is milled and sieved into three or four size grades: coarse, fine, very fine, and flour.
Coarse bulgur is usually boiled and consumed in a similar fashion to rice, while fine bulgur is often baked in an admixture with ground meat. The coarse bulgur must cook into a tender product with maximum retention of particle integrity when boiled. The fine bulgur must exhibit optimum binding ability when mixed with meat and baked.
Fine bulgur is mixed with meat or poultry. Kibbeh, a mixture of bulgur and meat, can be cooked in different ways and is one of the most popular foods consumed throughout the Middle East. Falafel, a deep-fried mixture of faba beans and bulgur, is a traditional food for both the rich and the poor in the Middle East. Salads, such as tabouleh, also can be prepared from bulgur.
Kishk is served as a hot porridge or gruel. Made from bulgur, it is rich in fiber and minerals. In the eastern Mediterranean and the Indian subcontinent, kishk is made using low fat yogurt, parboiled cracked wheat (bulgur), and salt. The dough is typically prepared as a 4:1 ratio of yogurt to bulgur. The mixture is kneaded daily for up to 6 d at 35oC (conditioning period), during which the bulgur hydrates. The dough is formed into nuggets, placed on trays, and dried in the sun for up to 7 d. The dried mixture is ground to powder.
Frekeh or Firik
Frekeh is also known as firik. Frekeh, a non-paste durum wheat product, is a staple food in North Africa and the Middle East, especially Syria. Frekeh is a parched green wheat that is used in the same way as rice, bulgur, and couscous. In the Near East, 2% of durum wheat is used to make frekeh. In contrast to bulgur, frekeh making is a localized village industry. In many villages in northwestern Syria, frekeh is one of the most important sources of income. Although, it is a small industry, an estimated 200 to 300 thousand tons of frekeh are made every year in the Middle East.
The best frekeh is made from the largest, hardest, and greenest grains. Therefore, durum wheat, especially cultivars with large kernels, is the most suitable wheat for making frekeh. When processed from wheat harvested in late-milk to mid-dough stages, roughly 13 to 16 d after anthesis, frekeh is more delicious than that processed at the full-ripe stage, probably due to the higher contents of free simple sugars. Kernels in the early stages of development have high concentrations of minerals and vitamins, particularly thiamin and riboflavin.
Frekeh is made from immature wheat during a one- to two-week period of grain filling. The wheat is swathed, hand gathered, and laid in the sun to partially dry. Frekeh is produced by two different procedures: roasting or boiling. In the roasting procedure, fire is used to burn off the awns, lemma, and palea from immature spikes. Care is taken to avoid excessive parching of the kernels. The fire scorches the grain, giving the frekeh a characteristic flavor. In the boiling procedure, the immature spikes are boiled in water for about 20 min. In either process, the scorched or boiled spikes are dried in the sun. The heads are either hand (small-scale) or mechanically (large-scale) threshed to separate the grain from the chaff. Winnowing in the wind cleans the threshed grain. Finally, the grain is stored in bulk before it is bagged.
Frekeh is prepared for eating by cooking it in water (1:2) for 20 min. and allowing it to cool for 5 min. A minimum amount of water is used to avoid leaching soluble nutrients. Consumption of frekeh resembles that of bulgur. Frekeh is used as a substitute for rice and bulgur in pilav. Frekeh can be either boiled or steamed and is served with lamb or poultry (Özkaya et al., 1999).
In the Middle East, mamuneih made from semolina cooked in water with butter and sugar is consumed as a hot breakfast cereal. In North America, large kernels of durum wheat are used to make a puffed durum wheat ready-to-eat breakfast cereal.
Durum Wheat Bread
Durum wheat is used to a larger extent in bread production in the Near East, Middle East, and Italy than in other parts of the world. In some Middle Eastern countries, 70% to 90% of durum wheat is used for bread . Several types of bread are made from durum wheat. Two-layered bread, khobz, is the most popular bread in Syria, Lebanon, and Jordan. In Egypt, two-layered bread is called baladi and shami. Single-layer bread also is popular, including tannur and saaj (Syria and Lebanon), Mountain bread and markouk (Lebanon), and mehrahrah. In Turkey, flat bread, tandir ekmegi, is made from durum wheat. Thirty percent and 18% of durum wheat in the Near East is used to make two-layered and single-layer breads, respectively.
Several kinds of bread are made in Italy from durum wheat, depending on the shape of the bread and the region of the country. The common breads include fresedde in the province of Bari, frasella in the province of Foggia, and frasedda, frisedda, and frisa in the province of Salerno. A round, flat bread, cafone, is produced in Bari. A wheel-shaped durum wheat bread, rote, is produced in the Bari and Foggia provinces. Sckanate is a large durum bread typically made in Minervino, Altamura, Bitonto, and Gargano.
Although some countries use durum wheat to produce different kinds of bread, the proper bread making quality has restricted its wider use. Based on the characteristics of certain proteins in the kernel, the differences between bread wheat and durum wheat can be attributed largely to their gluten protein properties, with durum wheat normally having weaker gluten than bread wheat. However, the development of strong gluten durum cultivars has improved the cooking quality of pasta products and improved the bread baking quality.
In the Middle East, several desserts are made from semolina. Deep-fried semolina dough (mushabak), baked semolina dough (hariseh), and baked semolina mixture with vegetable oil, sugar, and nuts (halva) are common desserts in Syria, Lebanon, and Jordan. In Germany, kugel is a sweet noodle pudding that is used as a dessert and now is being marketed in North America.