Changes in phenols contents from buckwheat sprouts during growth stage

Comparative Study of the Nutritional, Phytochemical, Sensory Characteristics and Glycemic Response of Cookies Enriched with Lupin Sprout Flour and Lupin Green Sprout

This study aimed to compare the nutritional, phytochemical, and sensory characteristics of wheat flour (WF) cookies enriched with different proportions of lupin sprout flour (LSF) and those with different proportions of lupin green sprout (LGS). To achieve this, a control cookie (CC); three cookies with 10%, 20%, and 30% of LSF, respectively, CLSF1, CLSF2, and CLSF3; and three other cookies (CLGS1, CLGS2, and CLGS3) with 10%, 20%, and 30%, respectively, were produced. The proximate composition of each cookie was analyzed using AOAC methods. Also, the measurements of the total polyphenol content, antioxidant activity, individual polyphenols, glycemic index, and a sensory analysis were carried out using recent and accurate methods. The contribution of the main nutrients from 100 g of product to the required daily dose was also calculated. Data analysis revealed that cookies with LSF were richer than cookies with LGS in protein, fat, and energy values. CLGS3 was 35.12%, 1.45%, and 5.0% lower in protein, fat, and energy content than CLSF3, respectively. On the other hand, CLSF3 was lower than CLGS3, with 48.2% and 12.4% in moisture and mineral substances, respectively. Both cookies were lower in carbohydrates than the CC (65.20 g/100 g). Still on the subject of micro- and macronutrients, cookies with LSF were richer than those with LGS in all the minerals analyzed. The study also revealed improvements in phytochemical properties, such as total and individual polyphenols and antioxidant activity with the percentage of lupin sprout flour addition. The sensory analysis revealed that, for LSF and LGS cookies, the 10% samples were the most appreciated by consumers, irrespective of the sensory attributes studied. The glycemic index of the CLSF2 product was lower compared to the CC. This study shows that the LSF cookies have better nutritional, phytochemical, and sensory values than the LGS cookies. LSF is, therefore, better suited than LGS to the enrichment of bakery products in general and cookies in particular. The paper provides significant information to estimate the contribution of the consumption of functional products based on lupin sprouts to the required daily dose of food nutrients and the impact on the glycemic index of fortified products.

Tartary Buckwheat (Fagopyrum tataricum) FtTT8 Inhibits Anthocyanin Biosynthesis and Promotes Proanthocyanidin Biosynthesis

Tartary buckwheat (Fagopyrum tataricum) is an important plant, utilized for both medicine and food. It has become a current research hotspot due to its rich content of flavonoids, which are beneficial for human health. Anthocyanins (ATs) and proanthocyanidins (PAs) are the two main kinds of flavonoid compounds in Tartary buckwheat, which participate in the pigmentation of some tissue as well as rendering resistance to many biotic and abiotic stresses. Additionally, Tartary buckwheat anthocyanins and PAs have many health benefits for humans and the plant itself. However, little is known about the regulation mechanism of the biosynthesis of anthocyanin and PA in Tartary buckwheat. In the present study, a bHLH transcription factor (TF) FtTT8 was characterized to be homologous with AtTT8 and phylogenetically close to bHLH proteins from other plant species. Subcellular location and yeast two-hybrid assays suggested that FtTT8 locates in the nucleus and plays a role as a transcription factor. Complementation analysis in Arabidopsis tt8 mutant showed that FtTT8 could not recover anthocyanin deficiency but could promote PAs accumulation. Overexpression of FtTT8 in red-flowering tobacco showed that FtTT8 inhibits anthocyanin biosynthesis and accelerates proanthocyanidin biosynthesis. QRT-PCR and yeast one-hybrid assay revealed that FtTT8 might bind to the promoter of NtUFGT and suppress its expression, while binding to the promoter of NtLAR and upregulating its expression in K326 tobacco. This displayed the bidirectional regulating function of FtTT8 that negatively regulates anthocyanin biosynthesis and positively regulates proanthocyanidin biosynthesis. The results provide new insights on TT8 in Tartary buckwheat, which is inconsistent with TT8 from other plant species, and FtTT8 might be a high-quality gene resource for Tartary buckwheat breeding.

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.

The Effects of Plasma-Activated Water Treatment on the Growth of Tartary Buckwheat Sprouts

The aim was to investigate the effects of buckwheat sprout treated with plasma-activated water (PAW) and their quality, nutrients (protein, amino acids, fat, and carbohydrates), functional active ingredients (total flavonoids, total phenolic acids, γ-gamma aminobutyric acid (GABA), and polysaccharides), and antioxidant activity during germination. PAW had no negative effects on the germination rate, but promoted the stem growth instead, which indicated 1.12-fold higher germination rate compared with the control group. The results of sensory evaluation demonstrated that the obtained sprouts were bright green, shinning, crisp and smooth, with sufficient moisture, and easy to chew. During germination (1–9 days), the water content, amino acids, and reducing sugars of sprouts showed an increasing trend and were basically higher in the PAW group than in the control group, while protein, carbohydrate, and crude fat presented a decreasing trend. The results were that the flavonoid, phenolic acid, γ-GABA, polysaccharides content, and antioxidant activity during germination showed a gradual upward trend but with slight differences, and the antioxidant properties of buckwheat sprouts might be related to the phenolic acid and polysaccharides content. These data show that the PAW treatment on buckwheat sprout have great potential as a dietary source of antioxidant function with health benefits.

New Insights into the Antioxidant Compounds of Achenes and Sprouted Buckwheat Cultivated in the Republic of Moldova

It is well known that both Fagopyrum esculentum species, buckwheat achenes and buckwheat germs, contain flavonoids, and that they can be considered functional foods. In the present study we have analyzed the total content of polyphenols (TPC) and flavonoids (TFC), as well as the antioxidant activity of buckwheat ahcenes originating from the Balti region, Republic of Moldova, and also of the buckwheat sprouts over seven days of germination. The content of phytochemicals in achenes and germinated buckwheat after three and seven days was determined by HPLC–MS analysis. Using the Folin–Ciocalteu method, we recorded an increase in TPC of 360%, and of 436% in TFC after seven days of buckwheat ahcene germination. We aimed to investigate the free radical scavenging properties of methanolic extracts from ahcenes and sprouted buckwheat. We identified and quantified flavonoids and lignans such as rutin, orientin, isoorientin, vitexin, quercetin, quercitrin, isorhamnetin, lutein, apigenin, catechins, coumestrol—which have countless beneficial effects on human health—using HPLC–MS. FTIR analysis also revealed the accumulation of phenolic compounds during germination. This is the first study on the identification and quantification of phytochemicals from buckwheat achenes and sprouts from the Balti region of the Republic of Moldova.

Stability of Enzyme-Modified Flavonoid C- and O-Glycosides from Common Buckwheat Sprout Extracts during In Vitro Digestion and Colonic Fermentation

Common buckwheat sprout (CBS) contains more flavone C-glycosides (FCGs) and flavonol O-glycosides (FOGs) than does common buckwheat seed. Both flavonoids in CBS are well known for providing benefits to human health. However, they are relatively less bioaccessible and more directly degradable to aglycone during digestion than are multiglycosylated flavonoids. To overcome such limitations, the water solubility and digestion stability of FCGs and FOGs were enhanced by transglycosylation using cyclodextrin glycosyltransferase. Gastric conditions had little effect on the stability of FCGs and FOGs and their enzyme-modified compounds. In contrast, under intestinal conditions, transglycosylated FCGs lost a glucose moiety and reverted to their parent compounds before transglycosylation. Under colonic fermentation using human fecal samples, the different profiles and concentrations of short-chain fatty acids were suggested to be mainly due to the presence of transglycosylated FCGs and FOGs. These findings indicate that the process of transglycosylation changes the bioaccessibility of flavonoids in CBS.

Strategic enhancement of genetic gain for nutraceutical development in buckwheat: A genomics-driven perspective

Buckwheat (Fagopyrum spp.) under the family Polygonaceae is an ancient pseudocereal with stupendous but less studied nutraceutical properties. The gluten free nature of protein, balanced amino acid profile and health promoting bioactive flavonoids make it a golden crop of future. Besides a scanty basic research, not much attention has been paid to the improvement of plant type and breeding of nutraceutical traits. Scanning of scientific literature indicates that adequate genetic variation exists for agronomic and nutritional traits in mainstream and wild gene pool of buckwheat. However, the currently employed conventional approaches together with poorly understood genetic mechanisms restrict effective utilization of the existing genetic variation in nutraceutical breeding of buckwheat. The latest trends in buckwheat genomics, particularly avalilabity of draft genome sequences for both the cultivated species (F. esculentum and F.tataricum) hold immense potential to overcome these limitations. Utilizing the transgenic hairy rot cultures, role of various transcription factors and gene families have been deduced in production and biosynthesis of bioactive flavonoids. Further, the acquisition of high-density genomics data coupled with the next-generation phenotyping will certainly improve our understanding of underlying genetic regulation of nutraceutical traits. The present paper highlights the application of multilayered omics interventions for tailoring a nutrient rich buckwheat cultivar and nutraceutical product development.

Effect of buckwheat extracts on acrylamide formation and the quality of bread

BACKGROUND

The presence of acrylamide in food has attracted wide attention and has raised concerns due to its potential toxic and carcinogenic effects. The phenolic compounds in buckwheat display strong antioxidant activity, which may affect the acrylamide levels. The aims of this study were to evaluate the effect of buckwheat extracts on acrylamide formation and the quality of the bread, and to investigate possible inhibitory mechanisms.

RESULTS

The extracts from Tartary buckwheat seeds, Tartary buckwheat sprouts, common buckwheat seeds, and common buckwheat sprouts reduced acrylamide level in bread by 23.5, 27.3, 17.0, and 16.7%, respectively. In addition, all four buckwheat extracts significantly (P < 0.05) reduced acrylamide levels in the asparagine / glucose system. There were significant positive correlations between total phenolic compound content, the antioxidant activity of the extracts, and the reduction in the acrylamide level. Evaluation of the organoleptic and textural properties indicated that the addition of the extracts did not significantly affect the crust color, aroma, taste, crumb appearance, and hardness of the bread.

CONCLUSION

This study showed that proper use of buckwheat extracts can reduce acrylamide levels in bread without having a significant impact on their properties. The study also revealed that a possible acrylamide formation inhibitory mechanism involved the Maillard reaction through the asparagine / glucose pathway. The study also provided useful information for the further application of buckwheat in improving food safety. © 2019 Society of Chemical Industry.

Dynamic changes in polyphenol compounds, antioxidant activity, and PAL gene expression in different tissues of buckwheat during germination

BACKGROUND

There is a growing interest in buckwheat germination regarding the improvement of its health benefits. The aims of this study were to evaluate the effects of germination on polyphenol compounds, antioxidant activity, and phenylalanine ammonia-lyase (PAL) gene expression in different tissues (cotyledon, hypocotyl, and radicle) of buckwheat sprouts during germination for 12 days, as well as to investigate their interactions.

RESULTS

Total polyphenol and total flavonoid contents, antioxidant activity, main polyphenol components, and PAL gene expression significantly increased during germination. On day 12, the rutin content in cotyledons was elevated to 88.6 g kg^-1 , which was 7.7-times and 39.4-times compared to those in buckwheat seeds and radicles, respectively. Meanwhile, chlorogenic acid in hypocotyls reached 7.84 g kg^-1 , which was 36.3-fold higher than those in radicles. However, the PAL gene showed the highest expression in radicles.

CONCLUSION

Present results showed that polyphenol compounds mainly accumulated in cotyledons and hypocotyls. There was a negative correlation between polyphenol compounds and PAL gene expression. The discrepancy suggested that polyphenol compounds might experience transportation within buckwheat sprouts. The study could provide useful information for further application of buckwheat in functional foods, and revelation of the correlation between bioactive components and related gene expressions. © 2018 Society of Chemical Industry.

Development and storage stability of buckwheat chips using response surface methodology (RSM)

Processing conditions (potato level, frying temperature and frying time) were optimized for the development of buckwheat based chips using response surface methodology (RSM). Moisture content, oil uptake, color values, hardness and overall acceptability (OAA) were used as indices of product quality. The polynomial regression model was fitted with R² values of 0.983, 0.982, 0.98, 0.996, 0.973, 0.984 and 0.985 for moisture content, oil uptake, L, a*, b* values, hardness, and OAA respectively indicating fitness of the models. Potato level and frying temperature showed a significant effect on all responses at linear and quadratic levels except frying temperature for OAA at the linear level and hardness at quadratic level. Frying time showed significant effect on a* value, b* value, hardness and OAA at linear level. Interaction between all processing variables had a significant effect on a* value. Interaction between potato level and frying temperature had significant negative effect on moisture content of buckwheat chips. Potato level (30%), frying temperature (169 °C) and frying time (51 s) were found to be the optimum processing conditions with maximum OAA (8.36). 0.33 a_w was established as the water activity at which maximum stability of chips was shown. Buckwheat chips packed in both polypropylene (PP) and metallised polyester (MP) remained stable and acceptable for 6 months at RT whereas for 3 and 6 months in PP and MP films respectively at 37 °C.

Alteration of biochemical parameters and microstructure of Fagopyrum esculentum Moench grain in process of germination

Biochemical parameters alteration of Fagopyrum esculentum Moench grain in process of germination was studied. It was found that during germination of Fagopyrum esculentum Moench grain within 24 hours the content of ascorbic acid, thiamine, nicotinic acids, pantothenic acids and routine was increased. The peptide composition of Fagopyrum esculentum Moench grain was studied by gel electrophoresis. The most significant alteration of reserve globulins structure are observed during germination phase from 20 till 24 hours. New low-molecular polypeptides appear during above mentioned period, that indicates embryonic awakening and synthesis of new protein compounds, mainly hydrolases. The process of proteolysis during germination of Fagopyrum esculentum Moench grain promotes a content increase of soluble fractions and sum of albumins and globulins. There is a significant decrease of insoluble protein residue during germination phase change. Chromatographic method was used to determine the change of carbohydrate composition of Fagopyrum esculentum Moench grains during germination. It was established that the content of total carbohydrates amount in grain extracts increases. Electron scanning microscopy revealed that after 12 hours germination of Fagopyrum esculentum Moench grain, swelling of starch grains and minor damage of their packaging in endosperm are observed. After 24 hours, endosperm of germinated grain significantly changed microstructure: starch grains and components of protein matrix had a vague outline, grain disintegration was observed. Evaluation of antioxidant activity of alcohol extract from Fagopyrum esculentum Moench grain germinated during 24 hours showed that percentage of DPPG free radicals inhibition increases with process prolongation. Thus, Fagopyrum esculentum Moench grain germinated within 24 hours is characterized by a high content of biologically active substances and can be used in food technologies for functional products development.

Advances in extraction and analysis of phenolic compounds from plant materials

Phenolic compounds, the most abundant secondary metabolites in plants, have received more and more attention in recent years because of their distinct bioactivities. This review summarizes different types of phenolic compounds and their extraction and analytical methods used in the recent reports, involving 59 phenolic compounds from 52 kinds of plants. The extraction methods include solid-liquid extraction, ultrasound-assisted extractions, microwave-assisted extractions, supercritical fluid extraction, and other methods. The analysis methods include spectrophotometry, gas chromatography, liquid chromatography, thin-layer chromatography, capillary electrophoresis, and near-infrared spectroscopy. After illustrating the specific conditions of the analytical methods, the advantages and disadvantages of each method are also summarized, pointing out their respective suitability. This review provides valuable reference for identification and/or quantification of phenolic compounds from natural products.

Effect of germinated grain flours on physicochemical characteristics of rice cakes, Seolgitteok

Minor grains and their germinated shoots such as buckwheat, Job's tears, and mungbean have diverse bioactive functionalities. In this study, the flours of grains and germinated grains were added to Korean rice cakes, known as Seolgitteok, and the effects on properties such as starch gelatinization and retrogradation were examined. The dietary fiber content, blue value index, amylogram, texture properties and sensory evaluation of Seolgitteok were also investigated. Rice flour amylogram results showed that addition of buckwheat, germinated Job's tears, and mungbean decreased starch setback, and that addition of buckwheat decreased consistency, which are related to slowed retrogradation. Buckwheat, especially when germinated, delayed starch retrogradation, which is one of the main drawbacks of rice cakes. Seolgitteok with added germinated buckwheat possessed preferable sensory qualities.

The Contribution of Buckwheat Genetic Resources to Health and Dietary Diversity

Despite several reports on the beneficial effects of buckwheat in prevention of human diseases, little attention has been devoted to the variability of biochemical and physiological traits in different buckwheat genetic resources. This review describes the biochemical evaluation of buckwheat genetic resources and the identification of elite genotypes for plant breeding and exploitation. The various types of bioactive compounds present in different varieties provide basic background information needed for the efficient production of buckwheat foods with added value. In this review, we will provide an integrated view of the biochemistry of bioactive compounds of buckwheat plants of different origin, especially of fagopyrin, proteins and amino acids, as well as of other phenolic compounds including rutin and chlorogenic acid. In addition to the genetic background, the effect of different growth conditions is discussed. The health effects of fagopyrin, phenolic acids, specific proteins and rutin are also presented.

Buckwheat phenolic metabolites in health and disease

Buckwheat (Fagopyrum esculentum Moench, F. tataricum Gaertner) groats and flour have been established globally as nutritional foods because of their high levels of proteins, polyphenols and minerals. In some regions, buckwheat herb is used as a functional food. In the present study, reports of in vitro studies, preclinical and clinical trials dealing with the effect of buckwheat and its metabolites were reviewed. There are numerous reports of potential health benefits of consuming buckwheat, which may be in the form of food, dietary supplements, home remedies or possibly pharmaceutical drugs; however, adverse effects, including those resulting from contamination, must be considered. There are reports of antioxidative activity of buckwheat, which contains high levels of rutin and quercetin. On the other hand, both cytotoxic and antigenotoxic effects have been shown. Reduction of hyperlipidaemia, reduction of blood pressure and improved weight regulation have been suggested. Consuming buckwheat may have a beneficial effect on diabetes, since lower postprandial blood glucose and insulin response have been reported. In addition, buckwheat metabolites, such as rutin, may have intrinsic protective effects in preserving insulin signalling. Rutin has also been suggested to have potential therapeutic applications for the treatment of Alzheimer’s disease. The literature indicates that buckwheat is safe to consume and may have various beneficial effects on human health.

Capillary Electrophoresis in Food and Foodomics

Quality and safety assessment as well as the evaluation of other nutritional and functional properties of foods imply the use of robust, efficient, sensitive, and cost-effective analytical methodologies. Among analytical technologies used in the fields of food analysis and foodomics, capillary electrophoresis (CE) has generated great interest for the analyses of a large number of compounds due to its high separation efficiency, extremely small sample and reagent requirements, and rapid analysis. The introductory section of this chapter provides an overview of the recent applications of capillary electrophoresis (CE) in food analysis and foodomics. Relevant reviews and research articles on these topics are tabulated including papers published in the period 2011-2014. In addition, to illustrate the great capabilities of CE in foodomics the chapter describes the main experimental points to be taken into consideration for a metabolomic study of the antiproliferative effect of carnosic acid (a natural diterpene found in rosemary) against HT-29 human colon cancer cells.

Characterization of bioactive agents in five types of marketed sprouts and comparison of their antihypertensive, antihyperlipidemic, and antidiabetic effects in fructose-loaded SHRs

Hypertension, hyperlipidemia, and diabetes are important precursors of cardiovascular disease. Here, we evaluated the antihypertensive, antihyperlipidemic, and antidiabetic potential of five types of sprouts in fructose-loaded spontaneously hypertensive rats (SHRs). Powdered sprouts (PSs) were produced from mung bean, broccoli, radish, and buckwheat sprouts and germinated soybeans by lyophilization. The PSs were analyzed for nutritional composition and bioactive agents (γ-aminobutyric acid [GABA], coenzyme Q10 [CoQ10], rutin, and myo-inositol-1,2,3,4,5,6-hexakisphosphate [IP6]) and functionally tested in SHRs given water containing 25 % fructose and diets containing 30 % PS for 46 days. All PSs were nutritionally rich in protein and dietary fiber. CoQ10, GABA/rutin, and GABA/IP6 were abundant in broccoli, buckwheat, and germinated soybean PSs, respectively. Mung bean, broccoli, and buckwheat PSs caused significant reductions in heart rates and/or serum triglycerides. Mung bean PS also significantly reduced serum total cholesterol. These data supported the antihypertensive and antihyperlipidemic potential of mung bean, broccoli, and buckwheat sprouts.

Effects of germination on the nutritional properties, phenolic profiles, and antioxidant activities of buckwheat

Germination is considered to be an effective process for improving the nutritional quality and functionality of cereals. In this study, changes of nutritional ingredients, antinutritional components, chemical composition, and antioxidant activities of buckwheat seeds over 72 h of germination were investigated, and the reasons for these changes are discussed. With the prolonged germination time, the contents of crude protein, reducing sugar, total phenolics, total flavonoids, and condensed tannins increased significantly, while the levels of crude fat, phytic acid, and the activity of trypsin inhibitor decreased. Phenolic compounds, such as rutin, vitexin, isovitexin, orientin, isoorientin, chlorogenic acid, trans-3-hydroxycinnamic acid, and p-hydroxybenzoic acid increased significantly during the germination process, which may be due to the activation of phenylalanine ammonialyase. The improvement of flavonoids led to significant enhancement of the antioxidant activities of germinated buckwheat. Germinated buckwheat had better nutritional value and antioxidant activities than ungerminated buckwheat, and it represented an excellent natural source of flavonoids and phenolic compounds, especially rutin and C-glycosylflavones. Therefore, germinated buckwheat could be used as a promising functional food for health promotion.

Purification and identification of antihypertensive peptides from fermented buckwheat sprouts

Buckwheat (Fagopyrum esculentum) is rich in antihypertensive compounds. This study investigated the effect of lactic-fermented buckwheat sprouts (neo-FBS) on level, identification, and potency of blood pressure-lowering (BPL) compounds. A single oral dose of 1.0 mg/kg body weight buckwheat sprouts (BS) in spontaneously hypertensive rats did not show significant BPL activity, whereas neo-FBS significantly decreased blood pressure. HPLC of neo-FBS identified two peaks absent in the profile of BS. The peak exhibiting potent BPL activity was fractionated, and six peptides (DVWY, FDART, FQ, VAE, VVG, and WTFR) and tyrosine were identified by LC-MS/MS and Edman degradation. Single oral dose administration of the peptides revealed significant BPL effect of all the peptides, with the most potent being DVWY, FQ, and VVG. DVWY, VAE, and WTFR are novel. This study demonstrates that lactic fermentation of BS produces new, highly potent antihypertensive peptides and increases active compounds GABA and tyrosine already present in BS.