Differences in Ratio of Carbon Stable Isotopes among Barley Grain Milling Fractions with Various Concentrations of Beta-Glucans.

The grains of three barley varieties were milled and sieved to obtain respective milling fractions with a content of beta-glucans (b-G) from 1.4 to 10.7%. The enriched fraction obtained by the extraction and precipitation contained 24.7% of b-G. The differences between the ratio of stable C carbon isotopes were established. Milling fractions with coarse particles had more beta-glucans and a more negative ratio of δ13C isotope in comparison to the respective intact barley grain. However, the enriched fraction had a less negative isotope ratio. So, it is not expected that the deviation from the stable isotope ratio of grain in milling fractions is the result of the content of b-G, but it depends on other barley grain constituents. In different parts of barley grain, there are substances with different stable isotope ratios, and by milling and sieving, they are assorted to the same milling fraction with most of the b-G. The method for determining the ratio of a stable carbon isotope in diverse barley grain fractions, applied in this investigation, is potentially opening the possibility for an additional method of screening the concentration of bioactive constituents in barley grain.

Impact of Rutin and Other Phenolic Substances on the Digestibility of Buckwheat Grain Metabolites.

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.

Phytochemistry, Bioactivities of Metabolites, and Traditional Uses of Fagopyrum tataricum.

In Tartary buckwheat (Fagopyrum tataricum), the edible parts are mainly grain and sprouts. Tartary buckwheat contains protecting substances, which make it possible for plants to survive on high altitudes and under strong natural ultraviolet radiation. The diversity and high content of phenolic substances are important for Tartary buckwheat to grow and reproduce under unfriendly environmental effects, diseases, and grazing. These substances are mainly flavonoids (rutin, quercetin, quercitrin, vitexin, catechin, epicatechin and epicatechin gallate), phenolic acids, fagopyrins, and emodin. Synthesis of protecting substances depends on genetic layout and on the environmental conditions, mainly UV radiation and temperature. Flavonoids and their glycosides are among Tartary buckwheat plants bioactive metabolites. Flavonoids are compounds of special interest due to their antioxidant properties and potential in preventing tiredness, diabetes mellitus, oxidative stress, and neurodegenerative disorders such as Parkinson's disease. During the processing and production of food items, Tartary buckwheat metabolites are subjected to molecular transformations. The main Tartary buckwheat traditional food products are bread, groats, and sprouts.

Molecular Shield for Protection of Buckwheat Plants from UV-B Radiation.

Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn.) and common buckwheat (Fagopyrum esculentum Moench) are adapted to growing in harsh conditions of high altitudes. Ultraviolet radiation at high altitudes strongly impacts plant growth and development. Under the influence of ultraviolet radiation, protecting substances are synthesized in plants. The synthesis of UV-B defense metabolites is genetically conditioned, and their quantity depends on the intensity of the ultraviolet radiation to which the plants and plant parts are exposed. These substances include flavonoids, and especially rutin. Other substances with aromatic rings of six carbon atoms have a similar function, including fagopyrin, the metabolite specific for buckwheat. Defensive substances are formed in the leaves and flowers of common and Tartary buckwheat, up to about the same concentration in both species. In comparison, the concentration of rutin in the grain of Tartary buckwheat is much higher than in common buckwheat. Flavonoids also have other functions in plants so that they can protect them from pests and diseases. After crushing the grains, rutin is exposed to contact with the molecules of rutin-degrading enzymes. In an environment with the necessary humidity, rutin is turned into bitter quercetin under the action of rutin-degrading enzymes. This bitterness has a deterrent effect against pests. Moreover, flavonoids have important functions in human nutrition to prevent several chronic diseases, including obesity, cardiovascular diseases, gallstone formation, and hypertension.

Breeding buckwheat for nutritional quality.

Common buckwheat (Fagopyrum esculentum Moench, CB) and Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn., TB) are used in human nutrition. The idea to screen in the haploid phase for genes affecting low amylose concentration opens the possibility for the effective search of low amylose (waxy) genotypes in CB populations. Self-pollinated homozygous plants of TB might allow us to use a part of endosperm for screening of amylose content. Phenolic substances have a significant inhibitory effect on the digestion of CB and TB proteins, thus metabolites may have impact on protein digestibility. Digestion-resistant peptides are largely responsible for the bile acid elimination. Breeding to diminish polyphenols and anti-nutritional substances might have negative effects on the resistance of plants against pests, diseases and UV-radiation. Bread and pasta are popular CB and TB dishes. During dough making most of CB or TB rutin is degraded to quercetin by rutin-degrading enzymes. The new trace-rutinosidase TB variety makes possible making TB bread with considerable amount of rutin, preserving the initial rutin from flour. Breeding CB and TB for larger embryos would make it possible to increase protein, rutin, and essential minerals concentration in CB and TB grain.

The Content of Dietary Fibre and Polyphenols in Morphological Parts of Buckwheat (Fagopyrum tataricum).

In this report, we presented the profile of polyphenolic substances in flowers, leaves, stalk and roots of Fagopyrum tataricum estimated by using RP-UHPLC-ESI-MS equipment (reversed-phase ultra-high-performance liquid chromatography electrospray ionisation mass spectrometry). The neutral detergent fibre, acid detergent fibre, acid detergent lignin, cellulose and hemicellulose were also determined. Flowers, leaves, stalk and roots showed varying levels of dietary fibre and polyphenols. The highest content of neutral and acid detergent fibre were found in the roots (63.92 and 45.45% d.m., respectively) while the most rich in phenolic compounds were flowers (4.8 mg/1 g d.m.). Root and stalk contained the highest level of cellulose, 38.70 and 25.57% d.m., respectively. Among the investigated polyphenolic substances such as: 2,6-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, 4-hydrobenzoic acid, caffeic acid, catechin, chlorogenic acid, fagopyrin, ferulic acid, myricetin, gallic acid, isovanilic acid, isovitexin, kaempferol, luteolin, p-coumaric acid, procyanidin B2, quercetin, quercetin 3-D galactoside, rutin, syringic acid and vitexin, we observed that the contents of rutin and chlorogenic acid were the highest. We found some correlation between dietary fibre fractions and individual phenolic substances. The levels of acid detergent fibre (ADF), cellulose and hemicellulose were negatively correlated with isovitexin, kaempferol, vitexin, fagopyrin, caffeic acid and procyanidin B2 content. In this investigation, two solvents (water and methanol) were estimated regarding their extraction efficiency of phenolic compounds. Taking these results into consideration, we recommend using methanol as the extractor to isolate chlorogenic acid, fagopyrin, kaempferol, procyanidin B2, quercetin, quercetin 3-D-galactoside, rutin, vitexin, and water for other investigated polyphenolic substances obtained from Fagopyrum tataricum.

FtSAD2 and FtJAZ1 regulate activity of the FtMYB11 transcription repressor of the phenylpropanoid pathway in Fagopyrum tataricum.

Little is known about the molecular mechanism of the R2R3-MYB transcriptional repressors involved in plant phenylpropanoid metabolism. Here, we describe one R2R3-type MYB repressor, FtMYB11 from Fagopyrum tataricum. It contains the SID-like motif GGDFNFDL and it is regulated by both the importin protein 'Sensitive to ABA and Drought 2' (SAD2) and the jasmonates signalling cascade repressor JAZ protein. Yeast two hybrid and bimolecular fluorescence complementation assays demonstrated that FtMYB11 interacts with SAD2 and FtJAZ1. Protoplast transactivation assays demonstrated that FtMYB11 acts synergistically with FtSAD2 or FtJAZ1 and directly represses its target genes via the MYB-core element AATAGTT. Changing the Asp122 residue to Asn in the SID-like motif results in cytoplasmic localization of FtMYB11 because of loss of interaction with SAD2, while changing the Asp126 residue to Asn results in the loss of interaction with FtJAZ1. Overexpression of FtMYB11or FtMYB11D126N in F. tataricum hairy roots resulted in reduced accumulation of rutin, while overexpression of FtMYB11D122N in hairy roots did not lead to such a change. The results indicate that FtMYB11 acts as a regulator via interacting with FtSAD2 or FtJAZ1 to repress phenylpropanoid biosynthesis, and this repression depends on two conserved Asp residues of its SID-like motif.

Fungal DNA in dust in Swedish day care centres: associations with respiratory symptoms, fractional exhaled nitrogen oxide (FeNO) and C-reactive protein (CRP) in serum among day care centre staff.

PURPOSE: To study associations between fungal DNA in day care centres, fractional exhaled nitric oxide (FeNO) and inflammatory markers in day care centre staff. METHODS: Totally, 62 staff (90 %) from five day care centres in Sweden participated. All were females. Settled dust was collected and analysed for five sequences of fungal DNA by quantitative PCR. Levels of FeNO (NIOX MINO 50 ml/min) and serum levels of eosinophilic cationic protein, myeloperoxidase (MPO) and high-sensitivity C-reactive protein in blood (HsCRP) were measured. Dynamic spirometry was performed, and dyspnoea was measured. Biomarkers and dyspnoea ratings were log-transformed, and associations were analysed by linear mixed models, adjusting for age, atopy, smoking, body mass index (BMI), ETS and dampness/mould at home. RESULTS: Geometric mean (GM) for FeNO was 15.3 ppb, 6% were smokers, 14% were obese, 31% were overweight and 18% had atopy. GM concentration was 2.16 × 10(5) cell equivalents (CE)/g for total fungal DNA, 2310 CE/g for Aspergillus/penicillium (Asp/Pen) DNA, 17 CE/g for Aspergillus versicolor DNA and 14 CE/g dust for Streptomyces DNA. FeNO was associated with total fungal DNA (p = 0.004), Asp/Pen DNA (p = 0.005) and Streptomyces DNA (p = 0.03). HsCRP was associated with total fungal DNA (p = 0.03) and BMI (p = 0.001). Dyspnoea was associated with Asp/Pen DNA (p = 0.04). Subjects with ETS at home had lower lung function (FEV1) (p = 0.03), and those with dampness/mould at home had lower MPO (p = 0.03). CONCLUSION: Fungal contamination in day care centres, measured as fungal DNA, can be a risk factor for airway inflammation, and CRP is associated with BMI.

Genomic insight into the origin, domestication, dispersal, diversification and human selection of Tartary buckwheat.

BACKGROUND: Tartary buckwheat, Fagopyrum tataricum, is a pseudocereal crop with worldwide distribution and high nutritional value. However, the origin and domestication history of this crop remain to be elucidated. RESULTS: Here, by analyzing the population genomics of 567 accessions collected worldwide and reviewing historical documents, we find that Tartary buckwheat originated in the Himalayan region and then spread southwest possibly along with the migration of the Yi people, a minority in Southwestern China that has a long history of planting Tartary buckwheat. Along with the expansion of the Mongol Empire, Tartary buckwheat dispersed to Europe and ultimately to the rest of the world. The different natural growth environments resulted in adaptation, especially significant differences in salt tolerance between northern and southern Chinese Tartary buckwheat populations. By scanning for selective sweeps and using a genome-wide association study, we identify genes responsible for Tartary buckwheat domestication and differentiation, which we then experimentally validate. Comparative genomics and QTL analysis further shed light on the genetic foundation of the easily dehulled trait in a particular variety that was artificially selected by the Wa people, a minority group in Southwestern China known for cultivating Tartary buckwheat specifically for steaming as a staple food to prevent lysine deficiency. CONCLUSIONS: This study provides both comprehensive insights into the origin and domestication of, and a foundation for molecular breeding for, Tartary buckwheat.

Tartary Buckwheat Grain as a Source of Bioactive Compounds in Husked Groats.

Tartary buckwheat (Fagopyrum tataricum Gaertn.) originates in mountain regions of Western China, and is cultivated in China, Bhutan, Northern India, Nepal, and Central Europe. The content of flavonoids in Tartary buckwheat grain and groats is much higher than in common buckwheat (Fagopyrum esculentum Moench), and depends on ecological conditions, such as UV-B radiation. Buckwheat intake has preventative effects in chronic diseases, such as cardiovascular diseases, diabetes, and obesity, due to its content of bioactive substances. The main bioactive compounds in Tartary buckwheat groats are flavonoids (rutin and quercetin). There are differences in the bioactivities of buckwheat groats obtained using different husking technologies, based on husking raw or pretreated grain. Husking hydrothermally pretreated grain is among the traditional ways of consuming buckwheat in Europe and some parts of China and Japan. During hydrothermal and other processing of Tartary buckwheat grain, a part of rutin is transformed to quercetin, the degradation product of rutin. By adjusting the humidity of materials and the processing temperature, it is possible to regulate the degree of conversion of rutin to quercetin. Rutin is degraded to quercetin in Tartary buckwheat grain due to the enzyme rutinosidase. The high-temperature treatment of wet Tartary buckwheat grain is able to prevent the transformation of rutin to quercetin.

Consumers' Preferences towards Bread Characteristics Based on Food-Related Lifestyles: Insights from Slovenia.

Consumers' recognition and understanding of food characteristics can have an important role when making purchase decisions. The current study analysed consumer preferences for bread, an important food in the diets of Central European countries. The study included a conjoint experiment on a representative sample of 547 adult consumers in Slovenia. The following bread attributes: functional ingredients (chia seeds, linseed, quinoa, and Tartary buckwheat); nutritional claims (low salt, high fibre, and high protein); and other claims (organic, free from additives, flour from Slovenia, and wholegrain) were studied. The results showed the strongest relative importance for functional ingredients (a mean relative importance of 83.9%). In addition, a deeper insight into consumer preference was investigated by a recently developed modular instrument for food-related lifestyles. Latent class cluster analysis (LCA) enabled the identification of four consumer segments (uninvolved, conservative, health-conscious, and moderate) with different preferences toward selected functional ingredients, nutrition, and other claims. The results provide insights that allow for a better understanding of consumer preferences for functional ingredients and claims, and new perspectives for bread marketing to different consumer segments based on food-related lifestyles. Identifying the drivers that affect bread purchasing and consumption can support reformulation activities and product promotion in the direction of reinforcing healthier food choices.

Comparative and population genomics of buckwheat species reveal key determinants of flavor and fertility.

Common buckwheat (Fagopyrum esculentum) is an ancient crop with a world-wide distribution. Due to its excellent nutritional quality and high economic and ecological value, common buckwheat is becoming increasingly important throughout the world. The availability of a high-quality reference genome sequence and population genomic data will accelerate the breeding of common buckwheat, but the high heterozygosity due to the outcrossing nature has greatly hindered the genome assembly. Here we report the assembly of a chromosome-scale high-quality reference genome of F. esculentum var. homotropicum, a homozygous self-pollinating variant of common buckwheat. Comparative genomics revealed that two cultivated buckwheat species, common buckwheat (F. esculentum) and Tartary buckwheat (F. tataricum), underwent metabolomic divergence and ecotype differentiation. The expansion of several gene families in common buckwheat, including FhFAR genes, is associated with its wider distribution than Tartary buckwheat. Copy number variation of genes involved in the metabolism of flavonoids is associated with the difference of rutin content between common and Tartary buckwheat. Furthermore, we present a comprehensive atlas of genomic variation based on whole-genome resequencing of 572 accessions of common buckwheat. Population and evolutionary genomics reveal genetic variation associated with environmental adaptability and floral development between Chinese and non-Chinese cultivated groups. Genome-wide association analyses of multi-year agronomic traits with the content of flavonoids revealed that Fh05G014970 is a potential major regulator of flowering period, a key agronomic trait controlling the yield of outcrossing crops, and that Fh06G015130 is a crucial gene underlying flavor-associated flavonoids. Intriguingly, we found that the gene translocation and sequence variation of FhS-ELF3 contribute to the homomorphic self-compatibility of common buckwheat. Collectively, our results elucidate the genetic basis of speciation, ecological adaptation, fertility, and unique flavor of common buckwheat, and provide new resources for future genomics-assisted breeding of this economically important crop.

Adaptative Responses of Common and Tartary Buckwheat to Different Altitudes.

Environmental conditions at different elevations are harsher at higher elevations and impose constraints upon plants. The response of common and Tartary buckwheats to environmental conditions at elevations between 300 and 1180 m above sea level (asl) was studied. In common buckwheat, grown at the highest elevation, there was an increased investment in secondary metabolism, and decreased investment in primary metabolism, since the production of UV-absorbing compounds was enhanced while the amounts of chlorophylls and carotenoids decreased. In Tartary buckwheat, the amounts of UV-absorbing compounds, chlorophylls and carotenoids were similar in plants grown at different elevations, indicating better adaptation to conditions at higher elevations. Common and Tartary buckwheat plants from Podbeze had thicker leaves than plants from the two other locations. This could be a response to high radiation in the very sunny position in Podbeze.

Tartary Buckwheat Flavonoids Improve Colon Lesions and Modulate Gut Microbiota Composition in Diabetic Mice.

Tartary buckwheat flavonoids (TBFs) exhibit diverse biological activities, with antioxidant, antidiabetes, anti-inflammatory, and cholesterol-lowering properties. In this study, we investigated the role of TBFs in attenuating glucose and lipid disturbances in diabetic mice and hence preventing the occurrence of diabetes-related colon lesions in mice by regulating the gut microbiota. The results showed that TBFs (1) reversed blood glucose levels and body weight changes; (2) improved levels of serum total cholesterol (TC), triglycerides (TGs), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and fasting insulin; and (3) significantly reduced diabetes-related colon lesions in diabetic mice. In addition, TBFs also affected the diabetes-related imbalance of the gut microbiota and enriched beneficial microbiota, including Akkermansia and Prevotella. The TBF also selectively increased short-chain fatty acid-producing bacteria, including Roseburia and Odoribacter, and decreased the abundance of the diabetes-related gut microbiota, including Escherichia, Mucispirillum, and Bilophila. The correlation analysis indicated that TBFs improved metabolic parameters related to key communities of the gut microbiota. Our data suggested that TBFs alleviated glucose and lipid disturbances and improved colon lesions in diabetic mice, possibly by regulating the community composition of the gut microbiota. This regulation of the gut microbiota composition may explain the observed effects of TBFs to alleviate diabetes-related symptoms.

New insights into globoids of protein storage vacuoles in wheat aleurone using synchrotron soft X-ray microscopy.

Mature developed seeds are physiologically and biochemically committed to store nutrients, principally as starch, protein, oils, and minerals. The composition and distribution of elements inside the aleurone cell layer reflect their biogenesis, structural characteristics, and physiological functions. It is therefore of primary importance to understand the mechanisms underlying metal ion accumulation, distribution, storage, and bioavailability in aleurone subcellular organelles for seed fortification purposes. Synchrotron radiation soft X-ray full-field imaging mode (FFIM) and low-energy X-ray fluorescence (LEXRF) spectromicroscopy were applied to characterize major structural features and the subcellular distribution of physiologically important elements (Zn, Fe, Na, Mg, Al, Si, and P). These direct imaging methods reveal the accumulation patterns between the apoplast and symplast, and highlight the importance of globoids with phytic acid mineral salts and walls as preferential storage structures. C, N, and O chemical topographies are directly linked to the structural backbone of plant substructures. Zn, Fe, Na, Mg, Al, and P were linked to globoid structures within protein storage vacuoles with variable levels of co-localization. Si distribution was atypical, being contained in the aleurone apoplast and symplast, supporting a physiological role for Si in addition to its structural function. These results reveal that the immobilization of metals within the observed endomembrane structures presents a structural and functional barrier and affects bioavailability. The combination of high spatial and chemical X-ray microscopy techniques highlights how in situ analysis can yield new insights into the complexity of the wheat aleurone layer, whose precise biochemical composition, morphology, and structural characteristics are still not unequivocally resolved.

Eating buckwheat cookies is associated with the reduction in serum levels of myeloperoxidase and cholesterol: a double blind crossover study in day-care centre staffs.

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.

Tartary Buckwheat in Human Nutrition.

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.

Concentrations of Phenolic Acids Are Differently Genetically Determined in Leaves, Flowers, and Grain of Common Buckwheat (Fagopyrum esculentum Moench).

Common buckwheat (Fagopyrum esculentum Moench) is a valuable source of proteins, B vitamins, manganese, tryptophan, phytochemicals with an antioxidant effect, and the natural flavonoid rutin. Due to its composition, buckwheat supports the human immune system, regulates blood cholesterol, and is suitable for patients with diabetes or celiac disease. The study aimed to compare the allocation of selected phenolic acids (neochlorogenic acid, chlorogenic acid, trans-caffeic acid, trans-p-coumaric acid, trans-sinapic acid, trans-ferulic acid) and flavonoids (rutin, vitexin, quercetin, kaempferol) in the leaves, flowers, and grain of buckwheat cultivars of different origin. The content of individual phenolics was determined by the HPLC-DAD method. The results confirmed the determining role of cultivar on the relative content of chlorogenic acid, trans-caffeic acid, trans-sinapic acid, vitexin, and kaempferol in buckwheat plants. A significantly negative correlation among concentrations of phenolic acids in different common buckwheat plant parts shows that there are different mechanisms of genetic influences on the concentration of phenolic substances in common buckwheat flowers, leaves, and grain. These differences should be taken into account when breeding buckwheat for a high concentration of selected phenolic substances.

Breeding Buckwheat for Increased Levels of Rutin, Quercetin and Other Bioactive Compounds with Potential Antiviral Effects.

Common buckwheat (Fagopyrum esculentum Moench) and Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn.) are sources of many bioactive compounds, such as rutin, quercetin, emodin, fagopyrin and other (poly)phenolics. In damaged or milled grain under wet conditions, most of the rutin in common and Tartary buckwheat is degraded to quercetin by rutin-degrading enzymes (e.g., rutinosidase). From Tartary buckwheat varieties with low rutinosidase activity it is possible to prepare foods with high levels of rutin, with the preserved initial levels in the grain. The quercetin from rutin degradation in Tartary buckwheat grain is responsible in part for inhibition of α-glucosidase in the intestine, which helps to maintain normal glucose levels in the blood. Rutin and emodin have the potential for antiviral effects. Grain embryos are rich in rutin, so breeding buckwheat with the aim of producing larger embryos may be a promising strategy to increase the levels of rutin in common and Tartary buckwheat grain, and hence to improve its nutritional value.

The temperature threshold for the transformation of rutin to quercetin in Tartary buckwheat dough.

The aim was to determine conditions under which rutin can be retained during production of Tartary buckwheat (Fagopyrum tataricum) dough. Tartary buckwheat flour was hydrothermally treated by mixing with water at 25, 40, 60, 80 and 95 °C, with unprocessed Tartary buckwheat flour as control. With hydrothermal treatments at 25, 40 and 60 °C, most of the rutin was transformed to quercetin. However, for hydrothermal treatments at 80 and 95 °C, rutin was retained due to denaturation of the rutin-degrading enzymes during hydrothermal treatment. This is the first report to describe a temperature threshold for denaturation of rutin-degrading enzymes in any buckwheat material. Tartary buckwheat dough produced at 95 °C contained 12 mg rutin/g dry matter. Based on these characteristics, dough from hydrothermally treated Tartary buckwheat is a promising, rutin-rich functional food material.