General Aspects

Buckwheat, or Fagopyrum esculentum, is a plant native to central and northeastern Asia. From there, it spread to Europe through Russia and Turkey in the 14th and 15th centuries, and later to North America. Its cultivation peaked in the 19th century, gradually declining up to the present day. However, in recent years, it has experienced growth due to the rise of gluten-free products and the nutritional quality of this grain.

Currently, its cultivation is centred in China and the countries of the former Soviet Union, mainly Russia and Ukraine, where around 90% of the world’s production is concentrated. Although primarily used for animal feed, it is also widely used for human consumption in certain areas of China, in the form of whole grains or flour. In the French Brittany region, its galettes, savoury crepes made with buckwheat flour, are very famous. And the use of these grains has increased worldwide, especially through health food stores.

Despite being called “wheat,” buckwheat is not a cereal but belongs to the Polygonaceae family, making it a gluten-free grain. It is often included in the pseudocereal group, or grains with a morphology and composition similar to cereals. Buckwheat has a triangular shape with pronounced edges and a grayish, dark brown, or almost black color, with a hard outer shell (corresponding to the grain’s pericarp) that usually needs to be removed before processing. This outer shell, once separated from the grain, can be used as filling for pillows and cushions.

After removing the shell, buckwheat grains can be sold whole or ground. Whole grains are used in dishes similar to rice, after cooking to gelatinize the starch and soften the grain. For milling, stone or roller mills are typically used, and although it is common to produce wholemeal flour, it is also possible to remove the outer layers of the grain, which are darker and more difficult to break during milling, through sifting.

Although there are various species of buckwheat, over 90% of the world’s production corresponds to common buckwheat (Fagopyrum esculentum). Alongside this, there are productions of the tartary variety (F. tartaricum) in the Himalayan region and in specific areas of North America.

Nutritional Value

Buckwheat grains, once the shell is removed, have a composition similar to cereals, with a high starch content (50-70% dry matter), protein percentages around 12-15% (similar to wheat), a lipid content ranging from 2-4%, approximately 7% fibre, and a significant amount of certain minerals and E and B group vitamins. Although buckwheat has a similar content to cereals, it has received very good press in terms of nutrition, which can be explained by some details about its starch, proteins, fibres, and bioactive components.

Among the nutritional advantages of buckwheat is its lower glycaemic index compared to cereals, something that seems to be related to the fine structure of the starch and a higher content of resistant starch. In fact, its behaviour in the gelatinization and retrogradation process is more similar to tuber starches than to cereals, with higher viscosities of cooked pastes. The amino acid balance of the proteins is also slightly more complete than in the case of cereals, and unlike cereals, the limiting amino acid is leucine rather than lysine. Thus, the nutritional quality of these proteins is better than that of cereals but not as good as some animal proteins such as those in eggs or milk. In terms of mineral content, buckwheat flour has a higher content of magnesium, zinc, potassium, phosphorus, copper, and manganese than most cereals. However, these, like cereals, are concentrated in the outer layers of the grain, so they are largely lost if these are removed during the milling process.

The components of buckwheat grain that have received the most attention nutritionally are fagopyritols, rutin, and quercetin. Fagopyritols are non-fermentable oligosaccharides that, although nutritionally function as fibres, often escape classical fibre analysis, as is the case with inulin and oligofructose. These compounds have shown effectiveness in lowering blood glucose levels, so their use has been proposed in diabetic patients. However, studies have analysed buckwheat extracts, and therefore much higher quantities than those ingested with buckwheat products, and there are no conclusive studies in humans, only in rats and other animals. Rutin and quercetin, on the other hand, are polyphenols with high antioxidant capacity that are concentrated in the husk and outer parts of the grain.

In general, although there are various studies that relate some compounds present in buckwheat or the consumption of buckwheat to its ability to lower cholesterol, reduce the risk of cardiovascular diseases, or reduce the risk of certain types of cancer, these are based on the consumption of high amounts of buckwheat or the compounds it contains. It should also be noted that most of these studies have been carried out in vitro (simulating what happens in the body) or with rats, not with humans, so confirmation would be necessary. Additionally, the amounts used in these studies are much higher than those found in a normal diet with a high presence of buckwheat. And, of course, the occasional consumption of some bread with low percentages of buckwheat will not provide any significant nutritional benefits. Furthermore, these potential advantages will be greatly reduced if the outer parts of the grain have been removed in the milling process. Therefore, the inclusion of whole buckwheat flour can help maintain a complete and balanced diet, provided it is based on other whole flours, but on its own and in the quantities typically consumed in Western diets, it does not provide significant nutritional benefits.

Use of Buckwheat Flour in Bread and Other Baked Products

The main problem with buckwheat flour is that it imparts strange aromas and flavours to the products it is incorporated into. In general, these flavours are rejected by most of the population, but there are exceptions. These strange flavours are less rejected in the case of white flours (non-wholemeal), but the use of these reduces nutritional advantages. The inclusion of these flours in wheat bread makes it difficult to produce these by diluting the gluten network, so it is usually used in small percentages, never exceeding 20-30%. In the development of gluten-free bread, where raw materials rich in starch (mostly starches and rice flours) do not have great nutritional quality, the inclusion of buckwheat flours, especially if they are whole, makes more sense. But the flavours it imparts and the negative effect on the volume of these breads, especially compared to cornstarch, mean it cannot be incorporated in high percentages. Thus, in most cases, it does not exceed 20%. The use of this flour, in slightly lower percentages (5%), can help mask some strange aromas typical of gluten-free bread, without the characteristic flavours of buckwheat being noticeable, as both are compensated.

In cakes and cookies, the use of buckwheat flour cannot be very high either, as the flavours it generates are not appreciated by most consumers. Although these products help mask strange flavours due to their higher sugar content and flavouring substances, it is not advisable to use more than 30% buckwheat, but it needs to be evaluated for each formulation.

Since the percentages of buckwheat flour used are not very high, differences in quality are usually not noticeable, but it will be convenient for aspects such as particle size and water absorption capacity to be regular, so that any differences do not affect the processing and quality of the final product.

More Information:

Gimenez-Bastida, J.A.; Zielinski, H. (2015) Buckwheat as a functional food and its effects on health. Journal of Agricultural and Food Chemistry, 63:7896-7913.

Gimenez-Bastida, J.A.; Piskula, M.; Zielinski, H. (2015) Recent advances in development of gluten-free buckwheat products. Trends in Food Science & Technology, 44:58-65.

Starowicz, M.; Koutsidis, G.; Zielinski, H. (2018) Sensory analysis and aroma compounds of buckwheat containing products-a review. Critical Reviews in Food Science and Nutrition, 58:1767-1779.

Wijngaard, H.H.; Arendt, EK (2006) Buckwheat. Cereal Chemistry, 83:391-401.

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