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.