Fagopyrin in Tartary buckwheat grain is partly degraded during the preparation of food products

Buckwheat grain is a valuable source of different phytochemicals: health promoting flavonoids (rutin), as well as substances such as phototoxic fagopyrin. Quantitative data on fagopyrin in buckwheat is rare and mainly refers to its concentration in green parts of the plant [1 – 4]. While there are some data on nutrients in different processed fractions, such as carbohydrates, proteins, lipids [5], and rutin [6], fagopyrin has never been studied in detail.

The aim of this study was to determine the content of fagopyrin and two flavonoids, rutin and quercetin, in Tartary buckwheat grains and their milling fractions, in different grain products, traditional as well as novel products, available on the market in Korea and Slovenia. Information about their content is important for designing food products and adapting the technology of grain or food processing. The results showed that after steaming, fagopyrin content in the grain decreased. The remaining fagopyrin was unequally distributed; the minor part was found in groats, and the majority in hulls. Concentration of rutin decreased in a similar manner, but to a lesser extent. In contrast to fagopyrin, rutin was concentrated in groats. In the bread making procedure, a minor decrease of fagopyrin was seen comparing its concentration in grains, dough, and bread, while large amounts of rutin were degraded to quercetin during baking. These results may stimulate further research on edible parts and products of buckwheat, in particular, the qualitative evaluation of fagopyrin content in relation to flavonoids, making possible the treatment process needed to obtain buckwheat products with the highest utilisation value.

Keywords: Tartary buckwheat, Fagopyrum tataricum, fagopyrin, rutin, quercetin.

References:

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