Treasure from garden: Bioactive compounds of buckwheat

Superfood consumers' exposure to selected heavy metals

Background: Superfood products are important components of the human diet, which may contain toxic heavy metals that have no beneficial function in the human body (e.g., cadmium, arsenic, mercury). Therefore, due to the high demand for these foods, maintaining their safety is a significant public health concern, resulting in an increasing number of studies in the field of health risk assessment due to population exposure to heavy metals. Aim: The aim of the study was to determine the concentration of selected heavy metals in individual superfood products. Methods: The research material consisted of 48 samples of selected superfood products such as flaxseed, chia seed, black cumin, goji berries, buckwheat, millet, almonds, quinoa and green tea. The collected samples were subjected to the mineralization process. In addition, an exposure assessment was performed by calculating the hazard quotient (HQ). Statistical analysis was performed using Statistica software for cadmium and arsenic. Results: The highest level of cadmium was observed in a sample of flaxseed (ground)-0.35 mg/kg. Again, the highest concentration of arsenic was found in green tea bags (21.94 mg/kg). The exposure assessment showed that the risk of adverse health effects is likely to occur with the consumption of flaxseed, almonds, quinoa and green tea at both the assumed average and maximum arsenic concentrations (HQ > 1). Conclusions: There are many foods on the market that contain heavy metals. The accumulation of various heavy metals in agricultural soils and edible crops should be regularly assessed to minimize public health problems.

Buckwheat: an underutilized crop with attractive sensory qualities and health benefits

The pseudocereal buckwheat is one of the ancient domesticated crops. The aim of the present review was to outline the potential of buckwheat as an agricultural crop and brings studies on buckwheat into a new larger perspective combining current knowledge in agricultural history and practice, nutritional and sensory properties, as well as possible benefits to human health. Historically, buckwheat was an appreciated crop because of its short growth period, moderate requirements for growth conditions, and high adaptability to adverse environments. Nowadays, interest in buckwheat-based food has increased because of its nutritional composition and many beneficial properties for human health. Buckwheat is a rich course of proteins, dietary fibers, vitamins, minerals, and bioactive compounds, including flavonoids. Moreover, it contains no gluten and can be used in the production of gluten-free foods for individuals diagnosed with celiac disease, non-celiac gluten sensitivity, or wheat protein allergies. Buckwheat is traditionally used in the production of various foods and can be successfully incorporated into various new food formulations with positive effects on their nutritional value and attractive sensory properties. Further research is needed to optimize buckwheat-based food development and understand the mechanism of the health effects of buckwheat consumption on human well-being.

Buckwheat Flour (Fagopyrum esculentum Moench)-A Contemporary View on the Problems of Its Production for Human Nutrition

Buckwheat is returning to the countries of Central Europe; there are several reasons for this: firstly, due to its interesting chemical composition (proteins, fibre, and phenolic compounds), which is reflected in its nutritional value and potential health benefits. Secondly, because buckwheat, and buckwheat flour especially, are suitable raw materials for the production of gluten-free foods. Buckwheat flours are classified similarly to wheat flours, but the different anatomy of wheat grains and buckwheat seeds makes this classification partly misleading. While wheat flours are largely produced by one standard process, the production process for buckwheat flours is more varied. For wheat and wheat flours, the basic quality parameters and their required ranges for different types of primary and secondary processing are clearly defined. This is not the case for buckwheat and buckwheat flours, and the definition of the parameters and their ranges that characterize its technological quality remain unclear. The standardization of quality parameters and production processes is likely to be necessary for the potential expansion of the use of buckwheat for food production and, in particular, for bakery products.

Insertion of ten amino acids into 13S globulin zero-repeat subunit improves trypsin digestibility in common buckwheat (Fagopyrum esculentum Moench) seeds

The 13S globulin zero-repeat subunit is resistant to trypsin and may have higher allergenicity than the 1-6 tandem repeat subunits in common buckwheat (Fagopyrum esculentum Moench). To explore alleles useful for lowering allergenicity, amplicon deep sequencing targeting the zero-repeat subunit gene was conducted in bulked genomic DNA from eight cultivars and landraces. The analysis identified a unique allele encoding a zero-repeat subunit with 10 amino acid insertion (10aa) at a position equivalent to the tandem repeat insertion. Prediction of its 3-D structure suggested that 10aa changes the β-hairpin structure in the non-10aa (native) subunit to a random coil, which is also found in 1- and 3- repeat subunits. Homozygotes of the 10aa allele were developed and showed that the 10aa subunit was more digestible than the native subunit. However, the 10aa subunit was still less digestible than the 1-6 repeat subunits, suggesting needs to explore unfunctional alleles.

Nutrition security, constraints, and agro-diversification strategies of neglected and underutilized crops to fight global hidden hunger

Introduction

Neglected and underutilized crop species (NUCS) or forbidden crops offer tremendous potential to combat malnutrition, poverty, and global hidden hunger. Since overdependence on a few dominant cereal crops, viz., rice, maize, and wheat, is insufficient to meet the global food energy intake, the identification, genetic improvement, and implementation of various policies for wenumerates comprehensive comparative analyses of the nutrient profile of staple crops vs. potent underutilized crops with reference to cultivation constraints and climate resilience with different agro-diversification strategies.

Methodology

The research databases Scopus, JSTOR, Web of Science, EBSCO, Google Scholar, ScienceDirect, PubMed, and Academic Search were searched using relevant research queries.

Result

Out of 2,345 hits, 99 articles pertinent to the subject domain showed that underutilized crops are nutritionally superior, contain health-promoting bioactive components, and are more climate resilient than cereal crops. However, several constraints hinder the efficient utilization of these crops.

Discussion

Despite underutilized crops' many health benefits, improved cultivation techniques for the large-scale production of these crops are still in their infancy. Most of the time, however, the scientific knowledge gleaned from various study domains stays within the scientific community. The most crucial need of the hour, therefore, is an efficient network structure connecting governments, farmers, researchers, and people in business. Moreover, care must be taken to ensure that the policies of governments and INGOs/NGOs are properly implemented within a NUCS framework.

High-quality Fagopyrum esculentum genome provides insights into the flavonoid accumulation among different tissues and self-incompatibility

Common buckwheat (Fagopyrum esculentum) and Tartary buckwheat (Fagopyrum tataricum), the two most widely cultivated buckwheat species, differ greatly in flavonoid content and reproductive mode. Here, we report the first high-quality and chromosome-level genome assembly of common buckwheat with 1.2 Gb. Comparative genomic analysis revealed that common buckwheat underwent a burst of long terminal repeat retrotransposons insertion accompanied by numerous large chromosome rearrangements after divergence from Tartary buckwheat. Moreover, multiple gene families involved in stress tolerance and flavonoid biosynthesis such as multidrug and toxic compound extrusion (MATE) and chalcone synthase (CHS) underwent significant expansion in buckwheat, especially in common buckwheat. Integrated multi-omics analysis identified high expression of catechin biosynthesis-related genes in flower and seed in common buckwheat and high expression of rutin biosynthesis-related genes in seed in Tartary buckwheat as being important for the differences in flavonoid type and content between these buckwheat species. We also identified a candidate key rutin-degrading enzyme gene (Ft8.2377) that was highly expressed in Tartary buckwheat seed. In addition, we identified a haplotype-resolved candidate locus containing many genes reportedly associated with the development of flower and pollen, which was potentially related to self-incompatibility in common buckwheat. Our study provides important resources facilitating future functional genomics-related research of flavonoid biosynthesis and self-incompatibility in buckwheat.

Changes in the Carbohydrate Profile in Common Buckwheat (Fagopyrum esculentum Moench) Seedlings Induced by Cold Stress and Dehydration

Plant species are sensitive to stresses, especially at the seedling stage, and they respond to these conditions by making metabolic changes to counteract the negative effects of this. The objectives of this study were to determine carbohydrate profile in particular organs (roots, hypocotyl, and cotyledons) of common buckwheat seedlings and to verify whether carbohydrate accumulation is similar or not in the organs in response to cold stress and dehydration. Roots, hypocotyl, and cotyledons of common buckwheat seedlings have various saccharide compositions. The highest concentrations of cyclitols, raffinose, and stachyose were found in the hypocotyl, indicating that they may be transported from cotyledons, although this needs further studies. Accumulation of raffinose and stachyose is a strong indicator of the response of all buckwheat organs to introduced cold stress. Besides, cold conditions reduced d-chiro-inositol content, but did not affect d-pinitol level. Enhanced accumulation of raffinose and stachyose were also a distinct response of all organs against dehydration at ambient temperature. The process causes also a large decrease in the content of d-pinitol in buckwheat hypocotyl, which may indicate its transformation to d-chiro-inositol whose content increased at that time. In general, the sucrose and its galactosides in hypocotyl tissues were subject to the highest changes to the applied cold and dehydration conditions compared to the cotyledons and roots. This may indicate tissue differences in the functioning of the protective system(s) against such threats.

Inhibition mechanism of α-glucosidase inhibitors screened from Tartary buckwheat and synergistic effect with acarbose

Tartary buckwheat has been shown to provide a good antihyperglycemic effect. However, it is unclear which active compounds play a key role in attenuating postprandial hyperglycemia. Presently, acetone extract from the hull of Tartary buckwheat had the best effect for α-glucosidase inhibition (IC₅₀ = 0.02 mg/mL). Twelve potential α-glucosidase inhibitors from Tartary buckwheat were screened and identified by the combination of ultrafiltration and high-performance liquid chromatography coupled with mass spectrometry. Myricetin and quercetin exhibited the highest anti-α-glucosidase activity with IC₅₀ values of 0.02 and 0.06 mg/mL, respectively. These inhibitors manifested different types of inhibition manners against α-glucosidase via direct interaction with the amino acid residues. The results of structure-activity relationships indicated that an increase in the number of -OH on the B-ring greatly strengthened α-glucosidase inhibitory activity, but glucoside and rutinoside replacement on the C-ring obviously weakened this influence. Furthermore, a synergistic effect was observed between inhibitors with different inhibition manners.

Effect of Calcium Hydroxide on Physicochemical and In Vitro Digestibility Properties of Tartary Buckwheat Starch-Rutin Complex Prepared by Pre-Gelatinization and Co-Gelatinization Methods

This study examined the effect of calcium hydroxide (Ca(OH)₂, 0.6%, w/w) on structural, physicochemical and in vitro digestibility properties of the complexed system of Tartary buckwheat starch (TBS) and rutin (10%, w/w). The pre-gelatinization and co-gelatinization methods were also compared. SEM results showed that the presence of Ca(OH)₂ promoted the connection and further strengthened the pore wall of the three-dimensional network structure of the gelatinized and retrograded TBS-rutin complex, indicating the complex possessed a more stable structure with the presence of Ca(OH)₂, which were also confirmed by the results of textural analysis and TGA. Additionally, Ca(OH)₂ reduced relative crystallinity (RC), degree of order (DO) and enthalpy, inhibiting their increase during storage, thereby retarding the regeneration of the TBS-rutin complex. A higher storage modulus (G') value was observed in the complexes when Ca(OH)₂ was added. Results of in vitro digestion revealed that Ca(OH)₂ retarded the hydrolysis of the complex, resulting in an increase in values in slow-digestible starch and resistant starch (RS). Compared with pre-gelatinization, the complex process prepared with the co-gelatinization method presented lower RC, DO, enthalpy, and higher RS. The present work indicates the potential beneficial effect of Ca(OH)₂ during the preparation of starch-polyphenol complex and would be helpful to reveal the mechanism of Ca(OH)₂ on improving the quality of rutin riched Tartary buckwheat products.

Principal Components and Cluster Analysis of Trace Elements in Buckwheat Flour

Essential trace elements are required at very low quantities in the human body but are essential for various physiological functions. Each trace element has a specific role and a lack of these elements can easily cause a threat to health and can be potentially fatal. In this study, inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma atomic emission spectrometry (ICP-AES) were used to determine the content of trace metal elements Ca, Fe, Cu, Mg, Zn, Se, Mo, Mn, and Cd in buckwheat flour. The content and distribution characteristics of trace metal elements were investigated using principal component and cluster analysis. The principal component analysis yielded a four-factor model that explained 73.64% of the test data; the cumulative contribution of the variance of the 1st and 2nd principal factors amounted to 44.41% and showed that Cu, Mg, Mo, and Cd are the characteristic elements of buckwheat flour. The cluster analysis divided the 28 buckwheat samples into two groups, to some extent, reflecting the genuineness of buckwheat flour. Buckwheat flour is rich in essential trace metal elements and can be used as a source of dietary nutrients for Mg and Mo.

Systematic Review of Human and Animal Evidence on the Role of Buckwheat Consumption on Gastrointestinal Health

BACKGROUND

Buckwheat is a commonly cultivated crop with growing evidence that it is beneficial to gastrointestinal (GI) health. This systematic review summarizes the role of buckwheat in modifying GI health outcomes and microbiomes.

METHODS

Four medical databases and Google Scholar were systematically searched. Clinical trials, observational studies, animal in vivo, and in vitro studies with human and animal GI-derived samples were included.

RESULTS

There were 32 studies (one randomized controlled trial [RCT], one non-randomized trial, 3 observational, 9 in vitro, and 18 animal in vivo studies) included. In preclinical studies, buckwheat extracts were observed to have cytotoxic potential against human-derived GI cancer cell lines. Animals fed with buckwheat had lower GI mucosal inflammation, higher alpha diversity in the GI microbiome, and higher levels of fecal short-chain fatty acids. Human evidence studies and clinical trials were limited and predominantly of moderate risk of bias. The majority of in vitro studies with GI-derived samples and in vivo studies were reliable without restrictions in study design.

CONCLUSION

In vivo and in vitro studies show that buckwheat may have potential GI benefits due to its anti-oxidant and anti-inflammatory potential; however, human evidence remains limited, and its impact on health in humans remains to be elucidated in future trials.

Effects of Heat-Moisture Treatment Whole Tartary Buckwheat Flour on Processing Characteristics, Organoleptic Quality, and Flavor of Noodles

The effects of heat-moisture treatment whole tartary buckwheat flour (HTBF) with different contents on the pasting properties and hydration characteristics of tartary buckwheat noodle mix flour (TBMF), dough moisture distribution, cooking properties, texture properties, and flavor of noodles were studied. The results showed that the optimal additional amount of HTBF is determined to be 40%. The peak viscosity, trough viscosity, breakdown value, and final viscosity decreased significantly, and the optimal cooking time of the noodles decreased with increasing HTBF. Compared with the sample without HTBF, HTBF addition increased the water absorption of the sample and decreased its water solubility. When the amount of HTBF >30%, the content of strongly bound water in dough increased significantly; at HTBF >40%, the water absorption and cooking loss of noodles increased rapidly, and the hardness of noodles was decreased; and with HMBF addition at 60%, the chewiness, resilience, and elasticity decreased. Moreover, HMBF addition reduced the relative content of volatile alkanes, while increasing the amount of volatile alcohols. HTBF addition also elevated the content of slow-digesting starch (SDS) and resistant starch (RS) in noodles, providing noodles with better health benefits in preventing chronic diseases. These results proved the possibility of applying heat-moisture treatment grains to noodles, and they provide a theoretical basis for the research and development of staple foods with a hypoglycemic index.

FaesAP3_1 Regulates the FaesELF3 Gene Involved in Filament-Length Determination of Long-Homostyle Fagopyrum esculentum

The identification downstream genes of floral organ identity regulators are critical to revealing the molecular mechanisms underlying floral morphogenesis. However, a general regulatory pathway between floral organ identity genes and their downstream targets is still unclear because of the lack of studies in nonmodel species. Here, we screened a direct downstream target gene, FaesELF3, of a stamen identity transcription factor, FaesAP3_1, in long-homostyle (LH) Fagopyrum esculentum moench by using yeast one-hybrid (Y1H) and dual-luciferase reporter (DR) assays. Furthermore, FaesAP3_1-silenced LH plants that produced flowers with part stamens or anthers homeotically converted into a tepaloid structure, and FaesELF3-silenced plants that had flowers with part stamens consisting of a short filament and empty anther (male sterile anther). All these suggested that transcription factor (TF) FaesAP3_1 directly activates FaesELF3 in order to regulate filament elongation and pollen grain development in LH buckwheat. Our data also suggested that other stamen development pathways independent of FaesAP3_1 remain in F. esculentum.

Effect of Tartary Buckwheat Bran Substitution on the Quality, Bioactive Compounds Content, and In Vitro Starch Digestibility of Tartary Buckwheat Dried Noodles

This study aimed to investigate the impact of partial replacement of Tartary buckwheat flour (TBF) with Tartary buckwheat bran flour (TBBF) on the quality, bioactive compounds content, and in vitro starch digestibility of Tartary buckwheat dried noodles (TBDNs). When the substitution of TBBF was increased from 0 to 35%, the cooking and textural properties decreased significantly (p < 0.05), while the content of bioactive compounds (phenolic, flavonoids and dietary fiber) increased significantly (p < 0.05). In addition, the substitution of TBBF decreased the starch digestibility of TBDNs. A 10.4% reduction in eGI values was observed in the TBDNs with 35% TBBF substitution compared to the control sample. The results of differential scanning calorimetry showed that with the increase of TBBF, TBDNs starch became more resistant to thermal processing. Meanwhile, the X-ray diffraction and Fourier transform infrared spectroscopy results revealed that the long- and short-range ordered structures of TBDN starch increased significantly (p < 0.05). Furthermore, the substitution of TBBF decreased the fluorescence intensity of α-amylase and amyloglucosidase. This study suggests that replacing TBF with TBBF could produce low glycemic index and nutrient-rich TBDNs.

Analysis of Phenolic Compounds in Buckwheat (Fagopyrum esculentum Moench) Sprouts Modified with Probiotic Yeast

Buckwheat sprouts are a source of various nutrients, e.g., antioxidant flavonoids, which have a positive effect on human health. This study analyzed the content of phenolic compounds and assessed their impact on the antioxidant and anti-inflammatory properties and dietary fiber in modified buckwheat sprouts. For this purpose, the buckwheat seeds were modified by adding Saccharomyces cerevisiae var. boulardii. The modified buckwheat sprouts showed a higher content of total phenol compounds (1526 µg/g d.w.) than the control sprouts (951 µg/g d.w.) and seeds (672 µg/g d.w.). As a consequence, a higher antioxidant activity and anti-inflammatory effect were noted. Probiotic-rich sprouts also had the highest content of total dietary fiber and its soluble fraction. A correlation between phenolic compounds and the antioxidant and anti-inflammatory effects, as well as dietary fiber, was shown. The interaction between dietary fiber and phenolic compounds affects the bioaccessibility, bioavailability, and bioactivity of phenolic compounds in food. The introduction of probiotic yeast into the sprouts had a positive effect on increasing their nutritional value, as well as their antioxidant and anti-inflammatory activity. As a consequence, the nutraceutical potential of the raw material changed, opening a new direction for the use of buckwheat sprouts, e.g., in industry.

Comparative proteomic analyses of Tartary buckwheat (Fagopyrum tataricum) seeds at three stages of development

Tartary buckwheat is among the valuable crops, utilized as both food and Chinese herbal medicine. To uncover the accumulation dynamics of the main nutrients and their regulatory mechanism of Tartary buckwheat seeds, microscopic observations and nutrient analysis were conducted which suggested that starch, proteins as well as flavonoid gradually accumulated among seed development. Comparative proteomic analysis of rice Tartary buckwheat at three different developmental stages was performed. A total of 78 protein spots showed differential expression with 74 of them being successfully identified by MALDI-TOF/TOF MS. Among them, granule bound starch synthase (GBSS1) might be the critical enzyme that determines starch biosynthesis, while 11 S seed storage protein and vicilin seemed to be the main globulin and affect seed storage protein accumulation in Tartary buckwheat seeds. Two enzymes, flavanone 3-hydroxylase (F3H) and anthocyanidin reductase (ANR), involved in the flavonoid biosynthesis pathway were identified. Further analysis on the expression profiles of flavonoid biosynthetic genes revealed that F3H might be the key enzyme that promote flavonoid accumulation. This study provides insights into the mechanism of nutrition accumulation at the protein level in Tartary buckwheat seeds and may facilitate in the breeding and enhancement of Tartary buckwheat germplasm.

Exploring the Valorization of Buckwheat Waste: A Two-Stage Thermo-Chemical Process for the Production of Saccharides and Biochar

To realize the utilization of the valorization of buckwheat waste (BW), a two-stage thermal-chemical process was explored and evaluated to produce saccharides and biochar. During the first stage, BW underwent a hydrothermal extraction (HTE) of varying severity to explore the feasibility of saccharides production; then, the sum of saccharides yields in the liquid sample were compared. A higher sum of saccharides yields of 4.10% was obtained at a relatively lower severity factor (SF) of 3.24 with a byproducts yield of 1.92 %. During the second stage, the contents of cellulose, hemicellulose, and lignin were analyzed in the residue after HTE. Enzymatic hydrolysis from the residue of HTE was inhibited. Thus, enzymatic hydrolysis for saccharides is not suitable for utilizing the residue after HTE of BW. These residues with an SF of 3.24 were treated by pyrolysis to produce biochar, providing a higher biochar yield of 34.45 % and a higher adsorption ability (based on methyl orange) of 31.11 % compared with pyrolysis of the raw BW. Meanwhile, the surface morphology and biomass conversion were analyzed in this study. These results demonstrate that the two-stage thermal-chemical process is efficient for treating BW and producing saccharides and biochar. This work lays a foundation for the industrial application of BW, and for improving the economic benefits of buckwheat cultivation.

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.

Tartary buckwheat FtF3'H1 as a metabolic branch switch to increase anthocyanin content in transgenic plant

Tartary buckwheat (TB) is a pseudocereal rich in flavonoids, mainly including flavonols and anthocyanins. The flavonoid 3'-hydroxylase (F3'H) is a key enzyme in flavonoid biosynthesis and is encoded by two copies in TB genome. However, its biological function and effects on flavonol and anthocyanin synthesis in TB have not been well validated yet. In this study, we cloned the full-length FtF3'H1 gene highly expressed in all tissues (compared with FtF3'H2) according to TB flowering transcriptome data. The corresponding FtF3'H1 protein contains 534 amino acids with the molecular properties of the typical plant F3'H and belongs to the CYP75B family. During the flowering stage, the FtF3'H1 expression was highest in flowers, and its expression pattern showed a significant and positive correlation with the total flavonoids (R ² > 0.95). The overexpression of FtF3'H1 in Arabidopsis thaliana, Nicotiana tabacum and TB hairy roots resulted in a significant increase in anthocyanin contents (p < 0.05) but a decrease in rutin (p < 0.05). The average anthocyanin contents were 2.94 mg/g (fresh weight, FW) in A. thaliana (about 135% increase), 1.18 mg/g (FW) in tobacco (about 17% increase), and 1.56 mg/g (FW) TB hairy roots (about 44% increase), and the rutin contents were dropped to about 53.85, 14.99, 46.31%, respectively. However, the expression of genes involved in anthocyanin (DFRs and ANSs) and flavonol (FLSs) synthesis pathways were significantly upregulated (p < 0.05). In particular, the expression level of DFR, a key enzyme that enters the anthocyanin branch, was upregulated thousand-fold in A. thaliana and in N. tabacum. These results might be attributed to FtF3'H1 protein with a higher substrate preference for anthocyanin synthesis substrates. Altogether, we identified the basic biochemical activity of FtF3'H1 in vivo and investigated its involvement in anthocyanin and flavonol metabolism in plant.

Dynamic transcriptome analysis suggests the key genes regulating seed development and filling in Tartary buckwheat (Fagopyrum tataricum Garetn.)

Tartary buckwheat is highly attractive for the richness of nutrients and quality, yet post-embryonic seed abortion greatly halts the yield. Seed development is crucial for determining grain yield, whereas the molecular basis and regulatory network of Tartary buckwheat seed development and filling is not well understood at present. Here, we assessed the transcriptional dynamics of filling stage Tartary buckwheat seeds at three developmental stages by RNA sequencing. Among the 4249 differentially expressed genes (DEGs), genes related to seed development were identified. Specifically, 88 phytohormone biosynthesis signaling genes, 309 TFs, and 16 expansin genes participating in cell enlargement, 37 structural genes involved in starch biosynthesis represented significant variation and were candidate key seed development genes. Cis-element enrichment analysis indicated that the promoters of differentially expressed expansin genes and starch biosynthesis genes are rich of hormone-responsive (ABA-, AUX-, ET-, and JA-), and seed growth-related (MYB, MYC and WRKY) binding sites. The expansin DEGs showed strong correlations with DEGs in phytohormone pathways and transcription factors (TFs). In total, phytohormone ABA, AUX, ET, BR and CTK, and related TFs could substantially regulate seed development in Tartary buckwheat through targeting downstream expansin genes and structural starch biosynthetic genes. This transcriptome data could provide a theoretical basis for improving yield of Tartary buckwheat.

Effect of Light Quality and Media Components on Shoot Growth, Rutin, and Quercetin Production from Common Buckwheat

Common buckwheat (Fagopyrum esculentum Moench) seeds are important nutritious grains that are widely spread in several human food products and livestock feed. Their health benefits are mainly due to their bioactive phenolic compounds, especially rutin and quercetin, which have a positive impact on heart health, weight loss, and diabetes management. In this study, we evaluated different media and light treatments for the in vitro cultures of common buckwheat (CB) in order to find the most optimum one producing the highest yield with the highest purity of these compounds. The subcultured treated samples included in this study were shoots, leaves, stems, hairy roots, and calli. From the several treated samples and under different light stress conditions, the best production was achieved by growing the shoots of common buckwheat in hormone-free media containing activated charcoal and exposing to blue light, attaining 4.3 mg and 7.0 mg/g of extracts of rutin and quercetin, respectively, compared to 3.7 mg of rutin/g of extract and traces of quercetin in the seeds of CB. Continuous multiplication of CB shoots in the media containing charcoal and different concentrations of kinetin produced an extract with 161 mg/g of rutin and 26 mg/g of quercetin with an almost 20-fold increase in rutin content. The rutin content under these conditions reached up to 16% w/w of the extract. The hairy root cultures of the leaves exposed to red light showed a significantly high yield of quercetin attaining 10 mg/g of extract. Large-scale production of CB shootlets under the best conditions were carried out, which enabled the isolation of pure quercetin and rutin using a simple chromatographic procedure. The identity and purity of the isolated compounds were confirmed through NMR and HPLC analyses.

Phenolic compounds in common buckwheat sprouts: composition, isolation, analysis and bioactivities

Phenolic compounds in common buckwheat sprouts (CBSs) have gained research interest because of their multiple health benefits. Phenolic acids, flavanones, flavonols, flavan-3-ols, and anthocyanins are important bioactive components of CBS that exhibit biological activities, including anti-inflammatory, antioxidant, anti-proliferative, and immunomodulatory effects. The isolation and quantitative and qualitative analyses of these phenolic compounds require effective and appropriate extraction and analytical methods. The most recent analytical method developed for determining the phenolic profile is HPLC coupled with a UV-visible detector and/or MS. This review highlights the extraction, purification, analysis, and bioactive properties of phenolic compounds from CBS described in the literature.

JA-induced FtBPM3 accumulation promotes FtERF-EAR3 degradation and rutin biosynthesis in Tartary buckwheat

Buckwheat accumulates abundant flavonoids, which exhibit excellent health-promoting value. Flavonoids biosynthesis is mediated by a variety of phytohormones, among which jasmonates (JAs) induce numerous transcription factors, taking part in regulation of flavonoids biosynthesis genes. However, some transcriptional repressors appeared also induced by JAs. How these transcriptional repressors coordinately participate in JA signaling remains unclear. Here, we found that the disruption of the GCC-box in FtF3H promoter was associated with flavonoids accumulation in Tartary buckwheat. Further, our study illustrated that the nucleus-localized FtERF-EAR3 could inhibit FtF3H expression and flavonoids biosynthesis through binding the GCC-box in the promoter of FtF3H. The JA induced FtERF-EAR3 gene expression while facilitating FtERF-EAR3 protein degradation via the FtBPM3-dependent 26S proteasome pathway. Overall, these results illustrate a precise modulation mechanism of JA-responsive transcription suppressor participating in flavonoid biosynthesis, and will further help to improve the efficiency of flavonoids biosynthesis in Tartary buckwheat.

A Risk and Hazard Analysis Model for the Production Process of a New Meat Product Blended With Germinated Green Buckwheat and Food Safety Awareness

This study was specifically designed for a small-scale meat processing enterprise “DARIYA” to set up a specific HACCP plan for the new product (patties) made from mixed horsemeat with vegetable components developed in the Department of Technology of Food Production and Biotechnology, Shakarim University of Semey. Critical control points (CCPs) were identified and applied in the HACCP plan. The different hazards were detected at each processing step, whereas each CCP in the HACCP plan was identified and accompanied with the appropriate significant hazard, critical limit, monitoring of the CCP, and corrective actions, confirming that the enterprise has fully employed the HACCP methodology and ISO 22000:2018. Our results indicate that during almost 1 year following the implementation of ISO 22000:2018, the coliform level of tested patties significantly dropped (p < 0.05) after 6 months of implementation (coliform count dropped from 4.4 MPN/g to 1.8 MPN/g). The rapid screening of the bacterial count, heavy metals, pesticide residue, and physical contamination levels also improved monitoring assertiveness, allowing them to deal with foreseeable issues linking to resources and guarantee product quality. Cesium-137 was recorded as 5.4 ± 2.9627 Bq/kg in horsemeat and 6.7 ± 2.7045 in poultry. The activity of cesium-137 did not exceed the MAC. This result discloses that prompt screening is the foremost and necessary step for small enterprises. According to this study, the “acceptance of raw materials” is the most important CCP, and their control, particularly in small-scale meat processing enterprises, can actually prevent many negative outcomes. The implementation of both standards improved food quality by declining the flaw rates for patties, and the number of flow inconsistencies needed for correction in the process also dropped significantly (p < 0.05), demonstrating that safety and quality points were improving. If the application of the HACCP plan were to continue over an extended period of time, the Food Safety Management System's (FSMS) benefits would be more substantial improvements to a greater number of items being monitored. The process of implementing HACCP principles and ISO 22000:2018 could be arduous but achievable enough to be used in small industries with significant outcomes.

Comparison of Heat and Drought Stress Responses among Twelve Tartary Buckwheat (Fagopyrum tataricum) Varieties

The use of orphan crops could mitigate the effects of climate change and improve the quality of food security. We compared the effects of drought, high temperature, and their combination in 12 varieties of Tartary buckwheat (Fagopyrum tataricum). Plants were grown at 21/19 °C or 28/26 °C under well-watered and water-stressed conditions. Plants were more discriminated according to environmental conditions than variety, with the exception of Islek that was smaller and produced fewer leaves, inflorescences, and seeds than the other varieties. The combination of high temperature and water stress had a stronger negative impact than each stress applied separately. The temperature increase stimulated leaf and flower production while water stress decreased plant height. Leaf area decreased with both temperature and water stress. High temperature hastened the seed initiation but negatively affected seed development such that almost all seeds aborted at 28 °C. At 21 °C, water stress significantly decreased the seed production per plant. At the physiological level, water stress increased the chlorophyll content and temperature increased the transpiration rate under well-watered conditions. High temperature also increased the polyphenol and flavonoid concentrations, mainly in the inflorescences. Altogether, our results showed that water stress and temperature increase in particular negatively affected seed production in F. tataricum.

Systematic analysis and expression profiles of TCP gene family in Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn.) revealed the potential function of FtTCP15 and FtTCP18 in response to abiotic stress

Background

As transcription factors, the TCP genes are considered to be promising targets for crop enhancement for their responses to abiotic stresses. However, information on the systematic characterization and functional expression profiles under abiotic stress of TCPs in Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn.) is limited.

Results

In this study, we identified 26 FtTCPs and named them according to their position on the chromosomes. Phylogenetic tree, gene structure, duplication events, and cis-acting elements were further studied and syntenic analysis was conducted to explore the bioinformatic traits of the FtTCP gene family. Subsequently, 12 FtTCP genes were selected for expression analysis under cold, dark, heat, salt, UV, and waterlogging (WL) treatments by qRT-PCR. The spatio-temporal specificity, correlation analysis of gene expression levels and interaction network prediction revealed the potential function of FtTCP15 and FtTCP18 in response to abiotic stresses. Moreover, subcellular localization confirmed that FtTCP15 and FtTCP18 localized in the nucleus function as transcription factors.

Conclusions

In this research, 26 TCP genes were identified in Tartary buckwheat, and their structures and functions have been systematically explored. Our results reveal that the FtTCP15 and FtTCP18 have special cis-elements in response to abiotic stress and conserved nature in evolution, indicating they could be promising candidates for further functional verification under multiple abiotic stresses.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08618-1.

Vitexin and Isovitexin Act Through Inhibition of Insulin Receptor to Promote Longevity and Fitness in Caenorhabditis elegans

SCOPE

Vitexin and isovitexin are natural plant nutraceuticals for human health and longevity. This research investigated the underlying mechanism of vitexin and isovitexin on aging and health. The vital role of DAF-2/IGFR was illustrated in the insulin/insulin-like growth signaling pathway (IIS) modulated by vitexin and isovitexin.

METHODS AND RESULTS

In vitro, in vivo models and molecular docking methods were performed to explore the antiaging mechanism of vitexin and isovitexin. Vitexin and isovitexin (50 and 100 μM) extended the lifespan of C. elegans. The declines of pharyngeal pumping and body bending rates, and the increase of intestinal lipofuscin accumulation, three markers of aging, were postponed by vitexin and isovitexin. These compounds inhibited the IIS pathway in a daf-16-dependent manner, subsequently increasing the expression of DAF-16 downstream proteins and genes in nematodes. Molecular docking studies demonstrated that these compounds might inhibit insulin signal transduction by binding to the crucial amino acid residue ARG1003 in the pocket of the insulin-like growth factor-1 receptor (IGFR). Western blot indicated that IGFR, PI3K and AKT kinase expressions in senescent cells is decreased after vitexin and isovitexin treatment.

CONCLUSION

Vitexin and isovitexin might inhibit IIS pathway by occupying the ATP-binding site pocket of IGFR, subsequently decreasing IGFR expression, thereby promoting longevity and fitness. This article is protected by copyright. All rights reserved.

Characterization of PISTILLATA-like Genes and Their Promoters from the Distyly Fagopyrum esculentum

Arabidopsis PISTILLATA (PI) encodes B-class MADS-box transcription factor (TF), and works together with APETALA3 (AP3) to specify petal and stamen identity. However, a small-scale gene duplication event of PI ortholog was observed in common buckwheat and resulted in FaesPI_1 and FaesPI_2. FaesPI_1 and FaesPI_2 were expressed only in the stamen of dimorphic flower (thrum and pin) of Fagopyrum esculentum. Moreover, intense beta-glucuronidase (GUS) staining was found in the entire stamen (filament and anther) in pFaesPI_1::GUS transgenic Arabidopsis, while GUS was expressed only in the filament of pFaesPI_2::GUS transgenic Arabidopsis. In addition, phenotype complementation analysis suggested that pFaesPI_1::FaesPI_1/pFaesPI_2::FaesPI_2 transgenic pi-1 Arabidopsis showed similar a flower structure with stamen-like organs or filament-like organs in the third whorl. This suggested that FaesPI_2 only specified filament development, but FaesPI_1 specified stamen development. Meanwhile, FaesPI_1 and FaesPI_2 were shown to function redundantly in regulating filament development, and both genes work together to require a proper stamen identity. The data also provide a clue to understanding the roles of PI-like genes involved in floral organ development during the early evolution of core eudicots and also suggested that FaesPI_1 and FaesPI_2 hold the potential application in bioengineering to develop a common buckwheat male sterile line.

Technological, sensory, nutritional and bioactive potential of pan breads produced with refined and whole grain buckwheat flours

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Breads made with 30% refined buckwheat flour or 30% whole grain buckwheat flour had minor interference in technological quality.

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Breads made with 30% or 45% whole grain buckwheat flour presented higher mineral contents.

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Breads made with refined buckwheat flour presented higher mineral bioaccessibility.

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After baking, rutin and quercetin levels increased, mainly in breads with 45% whole grain buckwheat flour.

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Breads made with 30% refined buckwheat flour or 30% whole grain buckwheat flour were well accepted by consumers.

The nutritional quality and bioactive potential of breads made with partial replacement of refined wheat flour (RWF) with 30% or 45% refined buckwheat flour (RBF) or whole buckwheat flour (WGBF) was assessed through mineral bioaccessibility, starch digestibility, dietary fiber content and bioactive potential by determining rutin and quercetin levels during processing. Moreover, technological quality and sensory acceptance were also evaluated. Breads made with 30% or 45% WGBF showed higher mineral and fiber contents compared to the control, while the formulations with RBF showed higher bioaccessibility. No changes were observed in the rutin levels of the dough before and after fermentation, but after baking, rutin and quercetin levels increased. The highest starch hydrolysis was found in the formulation containing 45% RBF. The formulations made with 30% RBF or 30% WGBF were well accepted by consumers. Our study shows interesting results, as few studies report the effect of processing on bioactive compounds.

Buckwheat and Amaranth as Raw Materials for Brewing, a Review

Globally, beer is considered the most-consumed low-alcohol beverage, it ranks third, after water and tea, in the top sales of these drinks. New types of beer are the result of the influence of several factors, including innovations in science and technology, changing requirements for food consumption of the population, competition between producers, promotion of food for health, flavor, and quality, the limited nature of traditional food resource raw materials, and the interest of producers in reducing production costs. Manufacturers are looking for new solutions for obtaining products that meet the requirements of consumers, authentic products of superior quality, with distinctive taste and aroma. This review proposes the use of two pseudocereals as raw materials in the manufacture of beer: buckwheat and amaranth, focusing on the characteristics that recommend them in this regard. Due to their functional and nutraceutical properties, these pseudocereals can improve the quality of beer-a finished product. Additionally, all types of beer obtained from these pseudocereals are recommended for diets with particular nutritional requirements, especially gluten-free diets. Researchers and producers will continue to improve and optimize the sensory and technological properties of the new types of beer obtained from these pseudocereals.

Comparative metabolomics study of Tartary (Fagopyrum tataricum (L.) Gaertn) and common (Fagopyrum esculentum Moench) buckwheat seeds

Tartary buckwheat has higher health-promoting value than common buckwheat. However, the related metabolites information except flavonoids is largely deficient. Here, we compared the seed metabolomes of the two species using a UHPLC-QqQ-MS-based metabolomics approach. In total, 722 metabolites were obtained, of which 84 and 78 were identified as the key active ingredients of Traditional Chinese Medicines and the active pharmaceutical ingredients for six major diseases-resistance, respectively. Comparative analysis showed there were obviously difference in metabolic profiles between the two buckwheat species, and further found 61 flavonoids and 94 non-flavonoids metabolites displayed significantly higher contents (≥2 fold) in Tartary buckwheat than in common buckwheat. Our results suggest that Tartary and common buckwheat seeds are rich in metabolites beneficial to human health, and non-flavonoids metabolites also contributed to Tartary buckwheat's higher health-promoting value than common buckwheat. This study provides valuable information for the development of new functional foods of Tartary buckwheat.

Buckwheat in Tissue Culture Research: Current Status and Future Perspectives

Buckwheat is a member of a genus of 23 species, where the two most common species are Fagopyrum esculentum (common buckwheat) and Fagopyrum tataricum (Tartary buckwheat). This pseudocereal is a source of micro and macro nutrients, such as gluten-free proteins and amino acids, fatty acids, bioactive compounds, dietary fibre, fagopyrins, vitamins and minerals. It is gaining increasing attention due to its health-promoting properties. Buckwheat is widely susceptible to in vitro conditions which are used to study plantlet regeneration, callus induction, organogenesis, somatic embryogenesis, and the synthesis of phenolic compounds. This review summarises the development of buckwheat in in vitro culture and describes protocols for the regeneration of plantlets from various explants and differing concentrations of plant growth regulators. It also describes callus induction protocols as well as the role of calli in plantlet regeneration. Protocols for establishing hairy root cultures with the use of Agrobacterium rhizogens are useful in the synthesis of secondary metabolites, as well as protocols used for transgenic plants. The review also focuses on the future prospects of buckwheat in tissue culture and the challenges researchers are addressing.

A short update on new approaches to celiac disease

Celiac disease is an autoimmune enteropathy of the small intestine, related to gluten intolerance occurring in genetically predisposed patients. Currently, the only available treatment is a lifelong gluten-free diet. However, the total avoidance of gluten is difficult and poses a challenge to patients, nutritionists and treating physicians. For this reason, scientists have developed in recent years new therapeutic approaches complementary to dietary treatment, such as modification of gluten to make gliadin non-toxic, reduction of the inflammatory response with elafin and Lactococcus Lactis, degradation of gluten by endoproteolytic enzymes, and correction of nutritional deficiencies by adding pseudo-cereals to the diet of celiac patients. This literature review focuses on the different treatment strategies for celiac disease previously studied and summarizes the latest advances in this field.

Effects of radio frequency heating on microbial populations and physicochemical properties of buckwheat

Microbial contamination is a persistent problem for grain industry. Many studies have shown that radio frequency (RF) heating can effectively reduce pathogens populations in low moisture foods, but there is a lack on the efficacy to decontaminate natural microbiome. The main objectives of this study were to investigate the effects of different RF heating conditions on natural microbial populations and physicochemical properties of buckwheat. In this study, 30 buckwheat samples collected from 10 different Provinces in China were analyzed for their microbial loads, and the samples with the highest microbial populations were used for further study to select the suitable RF heating conditions. The results showed that microbial loads in tested buckwheat kernels were in the range of 3.4-6.2 log CFU/g. Samples from Shanxi (SX-3) had significantly higher microbial counts than other samples. The selected four temperature-time combinations: 75 °C-20 min, 80 °C-10 min, 85 °C-5 min, and 90 °C-0 min of RF heating could reduce microbial counts to <3.0 log CFU/g in buckwheat kernels at 16.5% w.b. moisture content. Furthermore, the reduction populations of the inoculated pathogens (Salmonella Typhimurium, Escherichia coli, Cronobacter sakazakii, and Bacillus cereus) reached 4.0 log CFU/g under the above conditions, and almost 5.0 log CFU/g especially at high temperature-short holding time combinations (85 °C-5 min and 90 °C-0 min). Besides, physicochemical properties evaluation also showed the insignificant color changes and nutrients loss after RF treatment at 90 °C-0 min. Therefore, the RF heating at 90 °C-0 min holds greater potential than the other lower temperature-longer holding time combinations for applications in buckwheat pasteurization.

Elevation of brain magnesium with Swiss chard and buckwheat extracts in an animal model of reduced magnesium dietary intake

OBJECTIVES

Inadequate dietary magnesium (Mg) intake is a growing public health concern. Mg is critical for diverse metabolic processes including energy production, macromolecule biosynthesis, and electrolyte homeostasis. Inadequate free Mg²⁺ ion concentration ([Mg²⁺]) in the brain is associated with several neurological and behavioral disorders. Elevating [Mg²⁺]in the brain using oral Mg supplementation has proven to be challenging due to the tight regulation of Mg²⁺ transport to the brain. This study explored the effect of short-term moderate reduction in dietary Mg intake (87% of normal Mg diet for 30 days) on [Mg²⁺] in the cerebrospinal fluid (CSF) ([Mg²⁺]_CSF) and red blood cells (RBCs) ([Mg²⁺]_RBC) in adult male rats. In addition, we investigated the effectiveness of magnesium-rich blend of Swiss chard and buckwheat extracts (SC/BW extract) in increasing brain [Mg²⁺] compared to various Mg salts commonly used as dietary supplements.

METHODS

Animals were assigned to either normal or low Mg diet for 30 - 45 days. Following this, animals maintained on low Mg diet were supplemented with various Mg compounds. [Mg²⁺]_CSF and [Mg²⁺]_RBC were measured at baseline and following Mg administration. Anxiety-like behavior and cognitive function were also evaluated.

RESULTS

The present study showed that a short-term and moderate reduction in Mg dietary intake results in a significant decline in [Mg²⁺]_CSF and [Mg²⁺]_RBC and the emergence of anxiety-like behavior in comparison to animals maintained on normal Mg diet. Supplementation with SC/BW extract significantly elevated [Mg²⁺]_CSF and improved animal performance in the novel object recognition test in comparison with animals maintained on reduced Mg intake and supplemented with various Mg compounds.

DISCUSSION

These observations indicate that brain [Mg²⁺] is more sensitive to a short-term and moderate reduction in Mg dietary intake than previously thought and emphasizes the importance of dietary Mg in replenishing brain Mg²⁺ reserves.

Gluten-Free Cereal Products and Beverages: A Review of Their Health Benefits in the Last Five Years

In the past decades, food products and beverages made from gluten-free cereals were initially created for certain groups of people who experience gluten-related disorders such as wheat allergies, gluten ataxia, non-celiac gluten sensitivity, and the most well-known, celiac disease. Nowadays, the consumption of gluten-free products is not only restricted to targeted groups, but it has become a food trend for normal consumers, especially in countries such as the UK, the US, and some European countries, who believe that consuming a gluten-free product is a healthier choice compared to normal gluten-containing products. However, some research studies have disapproved of this claim because the currently available gluten-free products in the market are generally known to be lower in proteins, vitamins, and minerals and to contain higher lipids, sugar, and salt compared to their gluten-containing counterparts. The use of other gluten-free cereals such as sorghum, millet, and teff as well as pseudo cereals such as buckwheat and quinoa has gained significant interest in research in terms of their various potential health benefits. Hence, this review highlights the potential health benefits of some gluten-free cereals and pseudo cereals apart from corn and rice in the last decade. The potential health benefits of gluten-free products such as bread, pasta, crackers, and cookies and the health benefits of some other non-alcoholic beverages made from gluten-free cereals and pseudo cereals are reported.

The effects of extruded endogenous starch on the processing properties of gluten-free Tartary buckwheat noodles

The lack of gluten in Tartary buckwheat has always been the main limiting factor of their development. This paper explored how to improve the processing quality of gluten-free Tartary buckwheat noodles (GF-TBNs) by introducing extruded starch into Tartary buckwheat flour (TBF) and the underlying mechanism was also elucidated. Extruded Tartary buckwheat starch (ETBS) was obtained under different extrusion conditions. The thermal properties, molecular weight, and viscosity of ETBS were examined to determine the key parameters closely related to the water distribution and rheological properties of the dough sheet, and tensile properties of GF-TBNs. The results showed that ETBS with a low molecular weight and high viscosity contributed greatly to the GF-TBNs with good tensile properties. It is proposed that ETBS with a low molecular weight and high viscosity might form a gel-entrapped network inside GF-TBNs, which was confirmed by the morphology of GF-TBNs.

Isolation and Characterization of APETALA3 Orthologs and Promoters from the Distylous Fagopyrum esculentum

Common buckwheat (Fagopyrum esculentum) produces distylous flowers with undifferentiated petaloid tepals, which makes it obviously different from flowers of model species. In model species Arabidopsis, APETALA3 (AP3) is expressed in petal and stamen and specifies petal and stamen identities during flower development. Combining with our previous studies, we found that small-scale gene duplication (GD) event and alternative splicing (AS) of common buckwheat AP3 orthologs resulted in FaesAP3_1, FaesAP3_2 and FaesAP3_2a. FaesAP3_2 and FaesAP3_2a were mainly expressed in the stamen of thrum and pin flower. Promoters functional analysis suggested that intense GUS staining was observed in the whole stamen in pFaesAP3_2::GUS transgenic Arabidopsis, while intense GUS staining was observed only in the filament of stamen in pFaesAP3_1::GUS transgenic Arabidopsis. These suggested that FaesAP3_1 and FaesAP3_2 had overlapping functions in specifying stamen filament identity and work together to determine normal stamen development. Additionally, FaesAP3_2 and FaesAP3_2a owned the similar ability to rescue stamen development of Arabidopsis ap3-3 mutant, although AS resulted in a frameshift mutation and consequent omission of the complete PI-derived motif and euAP3 motif of FaesAP3_2a. These suggested that the MIK region of AP3-like proteins was crucial for determining stamen identity, while the function of AP3-like proteins in specifying petal identity was gradually obtained after AP3 Orthologs acquiring a novel C-terminal euAP3 motif during the evolution of core eudicots. Our results also provide a clue to understanding the early evolution of the functional specificity of euAP3-type proteins involving in floral organ development in core eudicots, and also suggested that FaesAP3_2 holds the potential application for biotechnical engineering to develop a sterile male line of F. esculentum.

Distribution of polyphenolic and sugar compounds in different buckwheat plant parts

The aim of this study was to provide information on the phenolic and sugar profiles of different parts of the buckwheat plant, which can define that buckwheat is a functional food, with a high nutritional value and very useful for human health. Therefore, the extracts of buckwheat leaf, stem, and flower, as well as buckwheat grain were analysed for the content of polyphenol and antioxidant tests. The identification of a notable number of phenolic compounds and quantification of sugars in different parts of buckwheat indicates that buckwheat is a highly valuable plant. A total of 60 phenolic compounds were identified (18 cinnamic acid derivatives, 14 flavonols, 13 flavan-3-ols (including proanthocyanidins), 10 hydroxybenzoic acid derivatives, and 5 flavones) using ultra-high-performance liquid chromatography (UHPLC), coupled with a hybrid mass spectrometer which combines the Linear Trap Quadrupole (LTQ) and OrbiTrap mass analyzer. The highest number of phenolic compounds was found in the analysed buckwheat flower sample, and then in the leaf, followed by the grain and the stem. In addition, the sugar profile of buckwheat leaf, stem, flower and grain, as well as the buckwheat pollen and the nectar was analysed. Hence, 16 sugars and 5 sugar alcohols were detected by the high-performance anion exchange chromatography (HPAEC) with a pulsed amperometric detector (PAD). Sucrose was found in a significant amount with the highest content in buckwheat leaf. Trisaccharides had similar accumulation in the sample extracts, while disaccharides dominated in buckwheat leaf, followed by nectar and pollen. The sugar alcohols showed the highest content in buckwheat grain, where erythritol was predominant. The obtained results show that buckwheat is very rich in phenolic compounds and sugars. In addition to grain, the other parts of the buckwheat plant can be used as a very good source of different classes of phenolic compounds. This study provides useful information on the distribution of phytochemicals in different parts of the buckwheat plant, which contribute to the maintaining of the status of buckwheat as a functional food.

The aim of this study was to provide information on the phenolic and sugar profiles of different parts of the buckwheat plant, which can define that buckwheat is a functional food, with a high nutritional value and very useful for human health.