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 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.

Bread can be a good source of nutrients as well as non-nutrient compounds. This study was designed to assess the effect of adding of sourdough and whey proteins to wholemeal (WM) bread produced by bake-off technology on chemical composition and bioavailability of proteins, calcium, phosphorus, magnesium and iron content in Wistar rats. Wholemeal breads were baked with using conventional or bake off technology. In breads chemical composition, selected minerals content, amino acid composition were measured. Five week-old Wistar rats (n = 30, male), were randomly divided into fi ve groups and fed with modified AIN-93G diets containing experimental breads. In animal study the nutritional value of breads' proteins and concentration of selected minerals in serum, liver and femoral bone, were measured. The body weight gain, biological value (BV) and net protein utilization (NPU) were significantly higher in rats fed with partially baked frozen wholemeal (PBF WM) bread with sourdough and whey proteins. The level of magnesium was significantly lower in serum of animals fed with the diet containing PBF WM bread with sourdough and whey proteins in comparison to rodents fed with conventional WM bread with sourdough. The content of iron was significantly higher in liver of rats fed with PBF WM with sourdough bread in comparison to the groups fed with conventional WM and conventional WM with sourdough breads. Sourdough addition can be recommended in a production of whole wheat partially baked frozen bread but its use is further more beneficial if it is fermented with whey proteins.

The aim of this study was to analytically evaluate the daily intake of total polyphenols, β-carotene, and vitamin C by 10- to 12-year-old children. Twenty four–hour dietary recalls were collected in spring and autumn 2006 from students in Krakow and Skawina (Malopolska region, Poland). The content of vitamin C, polyphenols, and β-carotene was determined in reconstructed daily diets. Statistical analysis did not show any significant differences between the mean intake of measured compounds according to school location, gender, or season. Diets of children contained adequate amounts of polyphenols in relation to the recommended values. Intake of β-carotene usually exceeded the recommended retinol equivalent; in contrast, vitamin C did not meet requirements. Increased consumption of fruits and vegetables rich in vitamin C is recommended.