Wheat, which has an important and undeniable history for humanity, has been in our lives for centuries. Today, wheat is grown in a very wide geography, these countries stretch from Asia to Europe, and are consumed in wider geographies. Wheat is produced on more than 240 million hectares in the world1. According to the data of FAO (Food and Agriculture Organization) for the last 5 years, an average of 750 million tons of wheat is produced every year2. Also, a rain-affected crop is used as a source of animal feed and in industry.

Well, what is the reason why so much wheat is produced in so many countries? The answer, of course, is the spread of the western-style diet. Thanks to the B vitamins, minerals, and other micronutrient sources it contains, wheat is the source of one-fifth of the energy needs of the world population3. Behind the nutritional value, especially in the lands we live in, wheat has a sacred place in terms of socio-culture and history. Because wheat symbolizes fertility in the land we live in. In addition, all over the world, wheat brought people together and helped them to start and develop civilizations.
The consumption of grain and bread as a staple food goes back to about 10 000 years ago in the Neolithic age. Archaeological studies, on the other hand, show that the place where it first emerged and spread to the world was the fertile crescent region covering southeast Turkey4. Bread is the most valuable product associated with wheat in our country. It has been combined with different flavors in different regions and similar products have been produced all over the world. It also manifests itself in different ways and cultures with names such as ‘pita’, ‘lavaş’, ‘tortilla’, and ‘chapati’.

With the breeding studies, the genetics of wheat has been changed and it continues to change. These studies have an important place in increasing the yield of wheat and protecting it from diseases and other abiotic factors5.
Gluten can be defined as the rubbery mass that remains when the wheat dough is washed to remove starch granules and water-soluble components6. If we look at the content of wheat, it is home to many different proteins, such as albumin, globulin, and mainly gliadin, glutenin. Similar proteins are also found in rye, barley, and oats as secalin, hordein, and avenins, respectively6. In general, glutenin and gliadin are referred to as prolamins, which are insoluble in water but soluble in aqueous ethanol6. If we think of gluten as a dough consisting of two components, the protein that adds viscosity is gliadin, while the protein that adds elasticity and stickiness is glutenin6. When gliadins are examined by gel electrophoresis, they are basically divided into four groups which are -, β -, γ -, ω – gliadins. More than a hundred components are reached when separated and analyzed by more modern techniques such as RP-HPLC (HPLC, known as high-performance liquid chromatography, is an analytical chemistry method used in the separation of mixtures). One of the determinants of dough quality is the molecular weights of glutenins7, and when examining the gluten proteins, the disulfide bonds it contains give key information about its structure. Disulfide formation occurs immediately after protein synthesis, as part of protein folding8. For example, these disulfide bonds change from grain to bread; factors such as environmental, genetic, and redox affect these changes7.

Gluten proteins: it has one of the most complex protein networks with their rich components, their genotypes, growing conditions, and processing processes. Many gaps need to be filled in this regard. In the developing and changing world, a better understanding of plants will help us better understand ourselves and solve many of our nutritional problems.
These currently ongoing problems are obesity, diabetes, gluten sensitivity, and gluten enteropathy (celiac disease). To find solutions to these problems, it is necessary to know the content of the grains well. For example, a cereal grain consists of three components: bark, germ, and endosperm, which collectively mean whole grains. And they are rich in B group vitamins except for vitamin B12, especially a good source of vitamin B1 (thiamine). They are also sources of nutrients such as iron, magnesium, selenium, and dietary fiber. Therefore, healthy people without gluten allergy or gluten enteropathy should include these grains in their daily lives. For healthy people to adopt a gluten-free diet habit for slimming purposes, it prevents the increase in the number of beneficial bacteria in the intestines, leading to the development of digestive system diseases9.
So what causes these diseases? A wheat allergy (a person can be allergic to any of the four wheat proteins, such as albumin, globulin, gliadin, and glutenin) occurs when a body produces antibodies against the proteins found in wheat9. For example, gliadin contains peptide sequences that are highly resistant to gastric, pancreatic, and intestinal digestion6. Whereas, Celiac disease is an abnormal immune system reaction to a certain protein (gluten) in wheat9. One of the things that are known for certain about celiac disease is that it is not a new disease. And the only known treatment, for now, is lifelong gluten-free diets.

Wheat, rye, barley, and oats (gluten-containing grains) are widely consumed all over the world. With the adoption of the Western-style diet, gluten is always among us from breakfast to dinner and snacks. However, due to genetic and environmental factors, some of the world’s population should stay away from gluten and similar proteins. Moreover, these diseases are not even new, humans have been struggling with these diseases for a long time. Hopefully, food scientists continue to work so that these people can continue their daily lives without any difficulties and not be deprived of some tastes.
References:
- Wheat in the world, B.C. Curtis, FAO , https://www.fao.org/3/y4011e/y4011e04.htm
- World Food Situation , Global cereal stocks in 2021/22 up; early prospects point to higher cereal production in 2022, Release date: 04/03/2022 https://www.fao.org/worldfoodsituation/csdb/en/
- Cummins, A. G., & Roberts‐Thomson, I. C. (2009). Prevalence of celiac disease in the Asia–Pacific region. Journal of gastroenterology and hepatology, 24(8), 1347-1351.
- Harlan, J. R. (1998). The living fields: our agricultural heritage. Cambridge University Press.
- Özberk, F., Karagöz, A., Özberk, İ., & Ayhan, A. T. L. I. (2016). Buğday genetik kaynaklarından yerel ve kültür çeşitlerine; Türkiye’de buğday ve ekmek. Tarla Bitkileri Merkez Araştırma Enstitüsü Dergisi, 25(2), 218-233.
- Wieser, H. (2007). Chemistry of gluten proteins. Food microbiology, 24(2), 115-119.
- Wieser, H., Bushuk, W., & MacRitchie, F. (2006). The polymeric glutenins. Gliadin and glutenin: The unique balance of wheat quality, 213-240.
- Kasarda, D. D. (1999). Glutenin polymers: The in vitro to in vivo transition. Cereal Foods World, 44, 566-571.
- Beslenmede Tahılların Yeri – Halk Sağlığı Genel Müdürlüğü https://hsgm.saglik.gov.tr/tr/beslenmehareket-haberler/beslenmede-tah%C4%B1llar%C4%B1n-yeri.html
Figure References:
- https://static.dw.com/image/61053455_303.jpg
- https://prairiecalifornian.com/wp-content/uploads/2014/12/The-History-of-Wheat-2.png
- https://onlinelibrary.wiley.com/cms/asset/2fe1262f-3123-427a-abd7-5f3cc3ecd1b4/jgh13703-fig-0001-m.jpg
- https://onlinelibrary.wiley.com/cms/asset/14e2ce51-46e0-41d9-963c-1d0cca6380fe/jgh13703-fig-0002-m.png
Inspector:Sülyman ŞAHİN