flavanols (catechin) and flavonols (rutin, quercetin) in the extracts and infusions, were found. Both extracts and infusions were the richest in ferulic acid. These studies indicate that the buckwheat leaves can be used for preparation of various types of tea and can also be introduced for consumers as the source of bioactive compounds.Keywords Buckwheat · Leaves · Extract · Infusion · Polyphenols · Antioxidant activity · Ferulic acid
IntroductionBuckwheat (Fagopyrum esculentum Moench) is an annual plant, which is cultivated mainly for seeds. Buckwheat seeds can be recognized as an important food source, because they contain proteins with high biological value and balanced amino acid composition as well as bioactive compounds, mainly polyphenols [1,2]. Buckwheat seeds are used to produce groats, flour, pasta and bread [3,4]. In China, leaves and flowers of buckwheat are also used in traditional medicine. Food producers utilize these parts of plant for tea production, which decreases cholesterol and glucose level in the blood. These properties are due to the high content of phenolic compounds and dietary fibre in the leaves of buckwheat [5]. Dietary fibre protects from hyperglycaemia, hypercholesterolaemia, obesity and some types of cancer, especially colon cancer [6].Most studies focus on chemical composition of buckwheat seeds as well as healthy properties [7][8][9][10]. In the available literature there are little data concerning the other parts of buckwheat. Therefore, there is a need to examine other parts of buckwheat, such as leaves, in terms of their chemical composition, content of bioactive compounds and antioxidant activity. Thus, it is very important to examine Abstract The objective of this study was to determine the chemical composition in the dried leaves and the content of bioactive compounds, antioxidant activity as well as the identification of polyphenolic compounds not only in extracts but also in infusions prepared from leaves of selected strains of buckwheat. To the best of our knowledge, it is the first comprehensive and in-depth study, which focuses on identification and quantitative determination of individual polyphenolic compounds of buckwheat leaves. Furthermore, the aim of presented research is to analyse the new, unknown strains of buckwheat. A statistically significant effect of strain on the content of individual components was observed. The extracts contained more polyphenols and were characterized by higher antioxidant activity than infusions. Strains DW15 and DWO Karzel were characterized by one of the highest contents of polyphenols, dietary fibre, protein, ash and antioxidant activity. Phenolic acids (3,5-diCQA, ferulic acid, sinapinic acid, p-coumaric acid), flavanones (hesperidin), flavonoids (isorhamnetin) as well as these by-products because this knowledge can be used in the prevention and treatment of the chronic non-communicable diseases. It would be possible to create novel functional food products and to better use of the byproduct of buckwheat production. The objecti...
