M.D. Oak, Genetics Department, Plant Science Division, Agharkar Research Institute, Agarkar Road, Pune 411004, India.; J.E. Dexter, Canadian Grain Commission, Grain Research Laboratory, 1404-303 Main St, Winnipeg MB, R3C 3G8 Canada.
Gliadin and Glutenin: The Unique Balance of Wheat Quality
Pages 281-305
DOI: https://doi.org/10.1094/9781891127519.013
ISBN: 978-1-891127-51-9
Abstract
Wheat was domesticated around 15,000 years ago in the Fertile-Crescent in present-day Turkey, Syria, Iraq and Iran. Cultivation of wild emmer and einkorn started in the early Neolithic period (Stone Age). Later, from the end of the Neolithic period through the Bronze age (6,000–3,000 years ago), the naked tetraploid sub-species of Triticum turgidum slowly replaced wild emmer wheat, and wheat cultivation spread around the world. Today, ssp. durum is the principal cultivated tetraploid wheat, ranking eighth among all cereals. Durum wheat is drought tolerant and, therefore, yields well under dry conditions. Estimated annual world durum-wheat production from 1994 to 2003 was 33 to 33.5 million tonnes, on an area of 17 to 17.8 million hectares, representing about 6 to 8% of total wheat production (International Grains Council 2004).
Durum wheat is very hard, so is usually milled into coarse flour known as semolina. The primary use for durum wheat around the world is extruded and dried pasta products, such as lasagna, macaroni, spaghetti, etc. Fresh pasta, which may be sheeted or extruded, can also be made from durum wheat. Other uses include specialty breads, couscous, frekeh and bulgur, particularly in Mediterranean countries (Liu et al 1996; Palumbo et al 2002).
Durum wheat breeding programs focus primarily on quality factors associated with pasta, because they are well defined, and pasta is the most universal durum wheat end-product (Feillet and Dexter 1996). It is assumed that genotypes suitable for pasta produce satisfactory couscous, frekeh and bulgar. Increasing interest in using durum wheat for baking may influence durum-wheat quality selection more in the future.
The concept of durum-wheat quality is complex and continually evolving in response to processing innovations, market pressure and consumer preference (Troccoli et al 2000; Dexter and Marchylo 2001). Gluten quantity and composition are the predominant factors associated with superior pasta texture. In this chapter, we review the genetics and the quantitative and qualitative aspects of durum-wheat gluten proteins, procedures to characterize and predict gluten viscoelasticity and dough properties, and selection of genotypes with superior pasta texture, with secondary emphasis on breadmaking quality.
