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With newly developed durum wheat genotypes such as high amylose content (to increase resistant starch) and soft durum (possible applications in noodles and biscuits) and purple durum wheat (to increase anthocyanins), there is plenty of opportunity for the durum wheat processing industry to develop functional foods from these durum wheat varieties, naturally rich in bioactive compounds, to meet and expand consumer demand.
World durum wheat production
The main durum-growing regions are the Middle East, southern Europe, North Africa, the former Soviet Union, North America and India. Worldwide, durum is grown on approximately 13 million hectares.
The International Grains Council (IGC) in its July 27 Grain Market Review projected world durum wheat production in 2017-18 at 38 million tonnes after a seven-year high of 39.9 million tonnes in 2016-17 with the E.U., Canada, Turkey, Mexico, the United States, Algeria, Morocco and Kazakhstan being major producers. According to the IGC, in 2017-18 global durum wheat consumption will reach 39.1 million tonnes, including 2.8 million tonnes for feed use.
According to U.S. Wheat Associates, the six classes of wheat grown in the United States are designated by color, hardness and their growing season: Hard red winter wheat, hard red spring wheat, soft red winter wheat, soft white wheat, hard white wheat and durum wheat, which is the hardest of all wheats and has a rich amber color with high protein content and gluten strength that is ideal for premium pasta, couscous and some Mediterranean bread.
“United States Standards for Wheat” defines “durum wheat” class as all varieties of white (amber) durum wheat and divides into the following three subclasses: Hard amber durum wheat, which is durum wheat with 75% or more of hard and vitreous kernels of amber color; amber durum wheat, with 60% or more but less than 75% of hard and vitreous kernels of amber color; and durum wheat, which has less than 60% of hard and vitreous kernels of amber color.
Durum wheat is adapted to more diverse environments than bread wheat, and it performs well in semiarid regions. In the United States, it is produced in two areas. The northern plains (North Dakota and Montana) grows hard amber durum, while the desert southwest (Arizona, California) grows desert durum under irrigation. The domestic market accounts for two-thirds of demand for U.S. durum supplies, while the export market accounts for one-third. About 20 countries purchase U.S. durum. Europe, as a region, is the single largest importer of U.S. durum, followed by African and Middle East markets, and Latin and South America. Customers in North African countries use durum wheat to make a granular, yellow, pasta-like product called couscous.
Durum wheat milling
Some of the unique characteristics of durum wheat compared to bread wheats are shown in the sidebar below. From a millers’ perspective, the large kernels, coupled with their hardness and vitreousness, are ideal for milling into the granular product semolina. The objective in durum wheat milling, as it pertains to pasta production, is to produce the maximum amount of semolina with the minimum amount of flour.
The bright yellow color of the endosperm that is carried over to the resultant semolina is of direct interest and value to the pasta manufacturer. One of the important quality parameters associated with good pasta is the presence of a bright yellow color, derived primarily from the durum wheat.
Durum wheat mill flows are different from common wheat mill flows, because the product preferred for premium pasta and couscous is uniformly sized semolina. Durum wheat is very hard, which facilitates high yield of semolina. Special attention to cleaning is required for durum wheat and it is tempered for a much shorter time than common wheat.
The break system for durum wheat is extended to allow gradual breakdown of kernels to achieve maximum production of semolina and minimum production of flour. Purified semolina from the break system is uniformly sized and freed from adhering bran by repeated sizing, grading and purification.
Most semolina is from sizing purifiers, making durum mills readily recognized by the large number of purifiers. The traditional durum wheat semolina particle size is coarser relative to what is used by modern pasta processors today, which tends to be finer.
Durum wheat for food use
In addition to its use in pasta, durum wheat is utilized for the production of different products such as bulgur, couscous, frekeh, puffed cereals, hot cereal, desserts, filler for pastries, and, in some areas of the world, various types of bread. Durum wheat has two main groups of consumers: European and American countries almost exclusively use durum wheat for pasta products, whereas in the Middle East and North Africa local breadmaking accounts for about half of durum wheat consumption, while the remaining half is used for pasta, couscous and various other uses. Furthermore, in the Mediterranean area and particularly in South Italy, durum wheat is used in the formulation of several types of bread.
Pasta products are manufactured primarily from semolina, durum granulars, and flour produced from the milling of durum wheat. To a lesser extent, farina and flour from common wheats are also used. In some countries, T. aestivum flour is not even allowed to be used for pasta production.
According to Mintel research, the compound annual growth rate for pasta between 2011 and 2015 was down 2% in Italy and the U.K. and completely flat in Australia, Canada, France and the United States.
“The trend for gluten-free and low-carb diets and the vilification of wheat as a contributor to a variety of ailments, including weight gain, have contributed to the flat and declining sales of pasta in many key markets,” said Jodie Minotto, a global food and drink analyst at Mintel.
In terms of new product development, the organic claim leads the way in Europe and the United States, according to Mintel. In the United States, average pasta consumption is forecast to reach 2.7 kilograms (nearly 6 pounds) in 2017, down 3.6% from 2015.
Although Italians are turning their backs on tagliatelle, pappardelle and fettuccine, according to Mintel, they remain in the top three pasta eating nations. In 2016, only the Brazilians and Russians consumed more.
The United States is the world’s second-largest manufacturer of pasta after Italy.
“All manner of ingredients are being used in next-generation pasta, the latest of which is seaweed,” Minotto said. “Sourdough fermentation is also being used to improve digestibility of gluten in wheat-based pasta.”
According to Euromonitor International, high fiber and chilled pasta are outperforming and will gain market share in the future.
Couscous, a pasta 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 Middle 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.
Bulgur has been one of the most important traditional durum wheat products in Turkey and Middle Eastern countries for ages. The product is a rapid-cooking, a ready or semi-ready-to-eat, rice-like product as such processes induce gelatinization of starch component. Bulgur can be made from bread wheat, durum, barley and maize. However, durum is preferred because of its hardness and amber color.
Other durum wheat products
Durum wheat traditionally is used in both flat and specialty bread, particularly in Mediterranean countries. It is used in breadmaking for several reasons such as to produce specialty-type bread products, increase value-added potential of durum wheat, and utilize durum first clear flour and better bread keeping quality.
The increasing use of durum wheat in more general breadmaking corresponds to an interest for these cultivars in alternative markets in years of high production to be used in place of bread wheat, either alone or in blends with bread wheat flour. In Italy, some types of durum bread are either protected denomination of origin or protected geographical indication status.
Although some countries use durum wheat to produce different kinds of bread, the proper breadmaking 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.
Frekeh, also known as firik. 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.
Durum wheat is also used to make several kinds of desserts in the Middle East.
Characteristic of durum wheats compared to common bread wheats
• Separate species (Triticum turgidum)
• Tetraploid (28 chromosomes) vs. other wheats hexaploid (42 chromosomes)
• Larger kernels
• Vitreous kernels
• Hardest of all wheat classes
• Amber in color
• High hectoliter weight and 1,000 kernel weight
• Endosperm has high concentration of xanthophyll pigments
• Semolina has bright amber color