Acta Scientiarum Polonorum Technologia Alimentaria

Background. Nutritive value of food is determined by its content of basic nutrients essential for the proper functioning of the human organism. Buckwheat grain is one of the most valuable raw materials for production of groats as well as functional food. It is characterized by high contents of starch, protein as well as dietary fibre. Apart from the above mentioned nutrients, buckwheat groats contain flavonoid compounds, playing the role of antioxidants. The aim of this study was to determine contents of dietary fibre and its fraction composition, thiamine and phenolic compounds in roasted buckwheat groats,
as well as antioxidant properties of ethanol buckwheat groats extracts.

Material and methods. Experimental material comprised roasted buckwheat groats purchased at a grocery shop. Contents of neutral detergent dietary fibre (NDF) and its fractions were determined by the detergent method according to Van Soest. Thermostable a-amylase (Termamyl 120 L) was used in the digestion of starch. Contents of total dietary fibre (TDF), soluble dietary fibre (SDF) and insoluble dietary fibre (IDF) were determined according to Asp et al. The content of thiamine was determined by the thiochrome method. Total polyphenol content was determined by colorimetry according to the Folina-Ciocalteu method. Antioxidant properties of extracts were estimated based on the capacity of extracts to scavenge the DPPH^• radical (1,1-diphenyl-2 picrylhydrazyl) and towards linolic acid. The capacity to inhibit self-oxidation of linolic acid was determined according to Lingnert et al.

Results. The NDF and TDF contents in buckwheat groats, amounting to 5.63 and 8.4%, respectively. The fraction found in biggest amounts was the hemicellulose fraction (3.42%). The level of the IDF fraction was much higher (5.94%) than that of SDF (2.46%). Thiamine content was 0.519 mg/100 g product, while the total content of phenolic compounds extracted from buckwheat groats was 30.592 μg·cm^-3. Ethanol extract of buckwheat groats was characterized by a high DPPH^• radical scavenging capacity (80.8%) and exhibited high capacity to inhibit self-oxidation of linolic acid W₀ = 0.86.

Conclusions. Investigations showed that buckwheat groats, widely used in Polish diet, due to their content of biologically active substances, may be a raw material for the production of functional food.