Buckwheat food is a good source of antioxidants, e.g. rutin, and other beneficial substances. Here we investigated the effects of the intake of common buckwheat (low rutin content) and tartary buckwheat cookies (high rutin content) on selected clinical markers. A double blind crossover study was performed among female day-care centre staffs (N = 62) from five day-care centres. Participants were randomly divided into two groups. The first group initially consumed four common buckwheat cookies per day (16.5 mg rutin equivalents/day) for two weeks, while the second group consumed four tartary buckwheat cookies per day (359.7 mg rutin equivalents/day). Then the groups switched their type of cookies and consumed them for another two weeks. We monitored selected clinical markers related to cardiovascular disease and lower airway inflammation, lung function, and subjective breathing difficulties in the staffs. Intake of tartary buckwheat cookies reduced the serum level of myeloperoxidase (MPO) by a factor 0.84 ( p = 0.02). When grouping the two types of buckwheat cookies together, there was a reduction of total serum cholesterol ( p < 0.001) and HDL-cholesterol ( p < 0.001) during the study period, with improved lung vital capacity ( p < 0.001). The degree of reduction in total and HDL cholesterol levels was similar in staffs with low and high body mass index (cut off 25). In conclusion, intake of tartary buckwheat cookies with high level of the antioxidant rutin may reduce levels of MPO, an indicator of inflammation. Moreover, intake of both types of buckwheat cookies may lower cholesterol levels.Keywords: antioxidant experiment; buckwheat; cholesterol; inflammation; lung function Tohoku J. Exp. Med., 2011, 225 (2), 123-130. © Tohoku University Medical PressThere is an increased interest in the beneficial health effects of dietary antioxidants intake, because they can help to prevent different types of diseases. Buckwheat is a good source of antioxidants, biologically high-valued amino acids (Krkoškova and Mrazova 2005;Jiang et al. 2007), dietary fiber (Bonafaccia et al. 2003), and minerals such as zinc, copper and manganese (Ikeda and Yamashita 1994). In Shanxi province, China, both common (Fagopyrum esculentum) and tartary (Fagopyrum tataricum) buckwheats are used to improve the health of patients with diabetes and cardiovascular diseases (Wieslander et al. 2000). A previous experimental buckwheat study concluded that intake of common buckwheat leaf tea could prevent further development of leg edema (Ihme et al. 1996), and a study by He et al. (1995) showed a cholesterol-lowering effect of buckwheat. However, there are very few studies on the health effects of buckwheat, especially buckwheat products in humans. Japanese studies indicate that some of the beneficial effects of buckwheat may be related to the low digestibility of buckwheat (Ikeda and Yamashita 1994). Skrabanja et al. (2001) reported beneficial effects of starch in common buckwheat with respect to insulin response. Buckwheat is also a good source of r...

Tartary buckwheat (Fagopyrum tataricum Gaertn.) originates in mountain areas of western China, and it is mainly cultivated in China, Bhutan, northern India, Nepal, and central Europe. Tartary buckwheat shows greater cold resistance than common buckwheat, and has traits for drought tolerance. Buckwheat can provide health benefits due to its contents of resistant starch, mineral elements, proteins, and in particular, phenolic substances, which prevent the effects of several chronic human diseases, including hypertension, obesity, cardiovascular diseases, and gallstone formation. The contents of the flavonoids rutin and quercetin are very variable among Tartary buckwheat samples from different origins and parts of the plants. Quercetin is formed after the degradation of rutin by the Tartary buckwheat enzyme rutinosidase, which mainly occurs after grain milling during mixing of the flour with water. High temperature treatments of wet Tartary buckwheat material prevent the conversion of rutin to quercetin.

The use of edible flowers (EF) in gastronomy is gaining popularity; however, there is still a lack of information about the factors that most contribute to the acceptance of this product. Therefore, the objective of this study was to investigate the habits associated with the usage of EF in gastronomy in three different countries (Portugal, Slovenia, and Brazil) and also to evaluate the major determinants for those habits. In addition, the level of knowledge was also investigated, particularly with regard to the aspects such as perceived risks of toxicity and pesticides. For that, a questionnaire survey of self-response was carried out on a sample of 559 participants, from the above-mentioned countries. To analyse the data, basic descriptive statistical tools were used combined with crosstabs and chi-square tests. Finally, a tree classification was performed using the classification and regression trees algorithm. The results revealed that, regardless of the country, the participants were familiar with the use of EF in gastronomy. The participants had, in general, already consumed EF, and their use was more popular between the Portuguese participants, being the Brazilian those who used them less. Significant differences were found between the countries in the form of consumption of EF and also in the types of EF consumed. There were also significant differences regarding the reasons for eating EF. The classification analysis showed that the country and the level of education were the major determinants for the consuming habits and knowledge about EF. This study highlighted that eating habits are very dependent on the customs and traditions of each country and helped understanding the factors that most affect the participants’ attitudes towards the consumption and knowledge of EF.

IZVLEČEK Raziskave vsebnosti flavonoidov, taninov in skupnih beljakovin v frakcijah zrn navadne ajde (Fagopyrum esculentum Moench) in tatarske ajde (Fagopyrum tataricum Gaertn.) Raziskovali smo vzorce zrnja oz. moke navadne ajde (F. esculentum Moench) in tatarske ajde (F. tataricum Gaertn.). Preučevali smo tri vzorce tatarske ajde iz Luksemburga ter dva vzorca navadne ajde iz Slovenije (cv. ´Darjo´in ´Sivo´). Z mletjem in presejanjem navadne ajde ´Darja´ in tatarske ajde smo pripravili štiri frakcije z različnimi granulacijami ter iz njihpripravili testo oziroma luščine in otrobe navlažili z vodo. S spektrofotometričnimi analizami smo spremljali deleže posameznih frakcij, vsebnost beljakovin in pepela v vseh mlevskih frakcijah in presejanih podfrakcijah ter koncentracijo flavonoidov in taninov v vzorcih moke in testa (liofilizirani vzorci). Tatarska ajda ima bistveno višjo vsebnost flavonoidov kot navadna ajda (tudi več kot 100-krat več v moki). Najvišja vsebnost flavonoidov je v mlevskih frakcijah tatarske ajde z granulacijo nad 100 µm do vključno 1000 µm in sicer 3,5-4,5 % flavonoidov/SS. Tako tatarska kot navadna ajda v vseh mlevskih frakcijah vsebujeta tanine; najvišja koncentracija taninov (0,8 %/SS pri navadni ajdi in 1,3 %/SS pri tatarski ajdi) je v mlevski frakciji z granulacijo nad 236 µm do vključno 1000 µm. Flavonoidi, pa tudi tanini, se po mlevskih frakcijah (z različno granulacijo) različno razporejeni. Razporeditev med mlevskimi frakcijami ni enaka pri tatarski in navadni ajdi. Različni vzorci tatarske ajde se med seboj razlikujejo po vsebnosti polifenolnih spojin, posebej velike so razlike v vsebnosti flavonoidov, manjše pa so razlike v koncentracijah taninov.

Tartary buckwheat (Fagopyrum tataricum Gaertn.) is grown in eastern and central Asia (the Himalayan regions of China, Nepal, Bhutan and India) and in central and eastern Europe (Luxemburg, Germany, Slovenia and Bosnia and Herzegovina). It is known for its high concentration of rutin and other phenolic metabolites. Besides the grain, the other aboveground parts of Tartary buckwheat contain rutin as well. After the mixing of the milled buckwheat products with water, the flavonoid quercetin is obtained in the flour–water mixture, a result of rutin degradation by rutinosidase. Heating by hot water or steam inactivates the rutin-degrading enzymes in buckwheat flour and dough. The low buckwheat protein digestibility is due to the high content of phenolic substances. Phenolic compounds have low absorption after food intake, so, after ingestion, they remain for some time in the gastrointestinal tract. They can act in an inhibitory manner on enzymes, degrading proteins and other food constituents. In common and Tartary buckwheat, the rutin and quercetin complexation with protein and starch molecules has an impact on the in vitro digestibility and the appearance of resistant starch and slowly digestible proteins. Slowly digestible starch and proteins are important for the functional and health-promoting properties of buckwheat products.