Tartary Buckwheat Bran: A Review of Its Chemical Composition, Processing Methods and Food Uses.

Tartary buckwheat (Fagopyrum tataricum Gaertn.) containing large amounts of functional compounds with antioxidant activity, such as rutin, has attracted substantial research attention due to its industrial applications. Particularly, the functional compounds in Tartary buckwheat bran, an unexploited byproduct of the buckwheat flour milling process, are more concentrated than those in Tartary buckwheat flour. Thus, Tartary buckwheat bran is deemed to be a potential material for making functional foods. However, a review that comprehensively summarizes the research on Tartary buckwheat bran is lacking. Therefore, we highlighted current studies on the chemical composition of Tartary buckwheat bran. Moreover, the processing method and food uses of Tartary buckwheat bran are also discussed.

Physicochemical Properties and In Vitro Digestibility of Starch from a Trace-Rutinosidase Variety of Tartary Buckwheat 'Manten-Kirari'.

We recently developed a novel Tartary buckwheat variety, 'Manten-Kirari', with trace-rutinosidase activity. The use of 'Manten-Kirari' enabled us to make rutin-rich food products with low bitterness. This study was intended to evaluate the physicochemical properties and in vitro digestibility of starch isolated from 'Manten-Kirari'. For comparison, the representative common buckwheat variety 'Kitawasesoba' and Tartary buckwheat variety 'Hokkai T8' in Japan were also used. The lowest content of amylose was found in 'Manten-Kirari' starch (18.1%) while the highest was in 'Kitawasesoba' starch (22.6%). 'Manten-Kirari' starch exhibited a larger median granule size (11.41 µm) and higher values of peak viscosity (286.8 RVU) and breakdown (115.2 RVU) than the others. The values of onset temperature for gelatinization were 60.5 °C for 'Kitawasesoba', 61.3 °C for 'Manten-Kirari', and 64.7 °C for 'Hokkai T8'. 'Manten-Kirari' and 'Hokkai T8' starches were digested more slowly than 'Kitawasesoba' starch. Our results will provide fundamental information concerning the expanded use of 'Manten-Kirari' in functional foods.

Development of Novel Detection Method for Rutinosidase in Tartary Buckwheat (Fagopyrum tataricum Gaertn.).

Contamination of rutinosidase is a major problem for rutin-rich food due to the hydrolysis of the functional compound rutin and generation of strong bitterness caused by the hydrolyzed moiety quercetin. This problem sometimes occurs between the trace and normal rutinosidase Tartary buckwheat varieties. Here, we developed a simple and rapid method for rutinosidase detection in 'ripening seeds using UV light' and in 'dough using alum-flavonoid complexation' from Tartary buckwheat (Fagopyrum tataricum Gaertn.). Normal rutinosidase seeds can be distinguished from trace-rutinosidase mature seeds and ripening young seeds using a rutin solution by comparing the muddiness, which corresponds to quercetin generation. In dough, we detected a threefold relative increase in rutinosidase activity corresponding to 1% contamination of normal rutinosidase flour with trace-rutinosidase flour within 65 min. These methods do not require expensive apparatuses and toxic chemicals and are therefore promising for detecting and preventing contamination by rutinosidase, e.g., in food processing factories.

Roasted Tartary Buckwheat Bran as a Material for Producing Rutin-Rich Tea Beverages.

Tartary buckwheat bran, a byproduct of buckwheat milling, is commonly treated as waste. The present study examined the rutin content during successive infusions of roasted Tartary buckwheat bran and grain to develop a functional Tartary buckwheat tea. Samples (6 g) of roasted Tartary buckwheat bran and grain were rinsed with 300 mL of hot water (>95 °C) for 0.5 min. For the first infusion test, the tea infusion sample of roasted Tartary buckwheat bran contained a distinctly higher amount of rutin (389 mg/L) than that of the roasted Tartary buckwheat grain (68 mg/L). Overall, rutin was more effectively extracted from roasted Tartary buckwheat bran, as compared to roasted Tartary buckwheat grain.

Breeding of Buckwheat to Reduce Bitterness and Rutin Hydrolysis.

Buckwheat (Fagopyrum esculentum) is recognized as an important traditional crop in some regions, and its taste is an important characteristic. Of the three cultivated buckwheat species, Tartary buckwheat (Fagopyrum tataricum) and perennial buckwheat (Fagopyrum cymosum) have strong bitterness in their seeds, which has prevented the wider use of the seeds of these varieties. In Tartary buckwheat, some studies have focused on the cause of strong bitterness generation. Tartary buckwheat seeds contain large amounts of the functional compounds rutin and rutinosidase, and rutin hydrolysis by rutinosidase has been found to be the trigger of rutin hydrolysis. Therefore, a variety with only a trace of rutinosidase and with reduced bitterness is required. The rutinosidase in Tartary buckwheat seeds consists of two major isozymes with very similar enzymatic characteristics, which can hydrolyze flour rutin within several minutes after the addition of water. Recently, the trace-rutinosidase variety Manten-Kirari in Tartary buckwheat was developed. The trace-rutinosidase characteristics were dominated by a single recessive gene. In 'Manten-Kirari' dough and foods, such as breads, confectionaries, and noodles, the rutin residual ratio was higher and bitterness was reduced compared to that of the normal-rutinosidase variety. In this review, we summarize the detailed research on the breeding of buckwheat related to reducing bitterness and rutin hydrolysis.

Present status and future perspectives of breeding for buckwheat quality.

Buckwheat is an important crop globally. It has been processed into cereal grain, noodles, confectionery, bread, and fermented foods for many years. Buckwheat production and processing has supported local economies and is deeply related to the culture of some regions. Buckwheat has many unique traits as a food, with a good flavor and color. In addition, buckwheat is also a healthy food because it contains bioactive compounds that have anti-oxidative, anti-hypertensive, and anti-obesity properties. Therefore, breeding of buckwheat for quality is an important issue to be addressed. Compared to other crops, there is still a lack of basic information on quality, including bioactive compounds generation and enhancement. However, some mechanisms for modifying and improving the quality of buckwheat varieties have recently been identified. Further, some varieties with improved quality have recently been developed. In this review, we summarize the issues around buckwheat quality and review the present status and future potential of buckwheat breeding for quality.

Physicochemical properties of potato starches manufactured in Hokkaido factories.

Potato starch is an important agricultural product in Hokkaido, the northernmost island of Japan, with output of around 0.18 million tons/year. The present investigation was conducted to evaluate the physicochemical properties of potato starch samples manufactured in 10 factories in Hokkaido. The starch samples were analyzed for pasting properties by rapid visco analyzer (RVA), gelatinization properties by differential scanning calorimetry (DSC), color components, and minerals, amylose, and resistant starch (RS) contents. The phosphorus and potassium contents of potato starches averaged 746 ppm and 681 ppm, ranging from 669 to 835 ppm and from 481 to 803 ppm, respectively. Relatively wide ranges were noted in the contents of sodium (35-134 ppm), magnesium (50-121 ppm), and calcium (34-164 ppm). RVA analysis revealed clear differences in peak viscosity (PV) and breakdown (BD) among starch samples examined. Higher contents of divalent cations, magnesium, and calcium, were associated with lower values of PV and BD, whereas the phosphorus content did not affect PV and BD. The differences in amylose content, DSC gelatinization properties and color components as well as RS content in raw starch were not large.

Preparation of iron-fortified potato starch and its properties.

Iron fortification was applied to commercial potato starch by immersion in different concentrations of ferrous sulfate (FeSO4) aqueous solutions. To determine the impact of iron fortification on the properties of potato starch, all of the starches obtained through the process mentioned above were analyzed for their pasting properties, color, gelatinization properties, and resistant starch content. Results indicated that the iron content markedly increased from 16 to 890 ppm when the potato starch was treated with a FeSO4 aqueous solution. During iron fortification, pasting properties markedly changed. Peak viscosity and breakdown decreased while peak viscosity temperature increased with iron fortification. Iron fortification caused a little reduced whiteness (slightly lower L*-value) and enhanced yellowish color (higher b*-value). In contrast, iron fortification had little influence on the gelatinization temperature and enthalpy. Moreover, no significant change in the resistant starch content was observed due to iron fortification.

Functional components in sweetpotato and their genetic improvement.

In addition to the nutritionally important components such as starches, vitamins and minerals, storage roots and leaves of sweetpotato (Ipomoea batatas) contains several components with health-promoting functions. Of these, the functionalities of carotenoids, anthocyanins and caffeoylquinic acids have been well established by in vitro and in vivo experiments. Several sweetpotato cultivars containing high levels of these components have been developed in Japan; e.g., 'Ayamurasaki', which has high amounts of anthocyanin in its storage roots. To further improve the content and also to change the composition of these functional components, the identification of the genes involved in their biosynthesis and genetic modification of the biosynthetic pathway has been attempted. In this review, we summarize the present status of the research and breeding for these functional components, and we discuss the future prospects for improving sweetpotato functionality.

Effects of a sweetpotato protein digest on lipid metabolism in mice administered a high-fat diet.

Sweetpotato peptide (SPP) was prepared by enzyme digestion of sweetpotato protein from starch wastewater. Animal experiments assessed the effect of SPP on body weight, abdominal adipose tissue mass, serum lipids and adipocytokines. Body and liver weight and epididymal and mesenteric fat of mice fed a high-fat diet containing 0.5% or 5% SPP for 28 days were significantly lower than control mice. Triglyceride and cholesterol in VLDL and LDL and leptin levels were significantly lower in the serum of SPP-administered mice compared to control mice. Biomarker arrays showed that adiponectin, melanocyte-stimulating-hormone-alpha and neuromedin U were more than 1.5 times higher, while TNF-alpha was about 1.5 times lower in the livers of SPP-administered mice compared to control mice. These results suggest SPP mitigated leptin resistance in mice administered a high-fat diet, and maintained anorexigenic peptide levels. SPP administration may suppress lipogenesis by increasing adiponectin levels and decreasing TNF-alpha levels in adipocytes.

Acute and Subacute Toxicity Studies on Rutin-Rich Tartary Buckwheat Dough in Experimental Animals.

In order to investigate the toxicity of rutin-rich dough from the Tartary buckwheat variety 'Manten-Kirari,' acute and subacute toxicity studies (10,000 and 5,000 mg/kg flour, respectively) were performed using rats. In the acute toxicity study, no toxic symptoms were observed and no rats died during the test. Body weight in the 'Manten-Kirari'-treated group was not significantly different when compared with that of the control group. On pathologico-anatomic observation, no unusual symptoms were observed in the 'Manten-Kirari'-treated group when compared with the control group. In the subacute toxicity study, no toxic symptoms were observed and no rats died during the test. Body weight and food intake in the 'Manten-Kirari'-treated and common buckwheat groups were not significantly different when compared with the control group. However, some investigated properties, such as urine protein and serum albumin, were significantly different in the 'Manten-Kirari' and common buckwheat groups when compared with the control group. However, these changes were not caused by toxicity, but by transient changes. On pathologico-anatomic observation, some abnormalities were observed in the liver, kidneys, heart, lung, bronchi and pituitary gland in some rats. However, the incidental rates in the 'Manten-Kirari' and common buckwheat groups did not differ when compared to controls. Therefore, these abnormalities may be caused by natural generation. Based on these results, we concluded that dough at a dose of 5,000 mg flour/kg is at a non effect level.

Preparation of calcium- and magnesium-fortified potato starches with altered pasting properties.

Calcium- and magnesium-fortified potato starches were prepared by immersion in various concentrations of CaCl2 and MgCl2 aqueous solutions, respectively. The pasting properties, i.e., peak viscosity and breakdown, of all the starches obtained above were analyzed using a Rapid Visco Analyzer. Furthermore, the gelatinization properties and in vitro digestibility of the representative calcium- and magnesium-fortified starches were tested. The maximum calcium content of the fortified potato starches was as high as 686 ppm with the addition of a high-concentration CaCl2 solution, while the calcium content of the control potato starch was 99 ppm. The magnesium content increased from 89 to 421 ppm by treatment of the potato starch with an MgCl2 solution. Markedly lower values of peak viscosity and breakdown were observed in calcium- and magnesium-fortified potato starches than in the control potato starch. However, the gelatinization temperature and enthalpy as well as resistant starch content of calcium- and magnesium-fortified potato starches were similar to those of the control potato starch. It is concluded that potato starches with altered pasting properties can be easily manufactured by the use of solutions containing high levels of calcium and magnesium.

Discovery and genetic analysis of non-bitter Tartary buckwheat (Fagopyrum tataricum Gaertn.) with trace-rutinosidase activity.

In a screening of about 500 lines of Tartary buckwheat, we identified lines that contained no detectable rutinosidase isozymes using an in-gel detection assay. We confirmed that seeds of these individuals had only a trace level of in-vitro rutinosidase activity. To investigate the heritability of the trace-rutinosidase characteristic, we analyzed the progeny of crosses between rutinosidase trace-lines, 'f3g-162', and the 'Hokkai T8'. The F2 progeny clearly divided into two groups: those with rutinosidase activity under 1.5 nkat/g seed (trace-rutinosidase) and those with activity over 400 nkat/g seed (normal rutinosidase). The segregation pattern of this trait in F2 progeny exhibited 1 : 3 ratio (trace-rutinosidase : normal rutinosidase), suggesting that the trace-rutinosidase trait is conferred by a single recessive gene; rutinosidase-trace A (rutA). In addition, sensory panelists evaluated the bitterness of flour from trace-rutinosidase individuals and did not detect bitterness, whereas flour from normal rutinosidase individuals was found to have strong bitterness. Although at least three bitter compounds have been reported in Tartary buckwheat seeds, our present findings indicate that rutin hydrolysis is the major contributing factor to bitterness. In addition, the trace-rutinosidase line identified here, 'f3g-162', is a promising material for generating a non-bitter Tartary buckwheat variety.

Breeding of 'Manten-Kirari', a non-bitter and trace-rutinosidase variety of Tartary buckwheat (Fagopyrum tataricum Gaertn.).

Here, we developed a new Tartary buckwheat cultivar 'Manten-Kirari', whose flour contains only trace amounts of rutinosidase and lacked bitterness. The trace-rutinosidase breeding line 'f3g-162' (seed parent), which was obtained from a Nepalese genetic resource, was crossed with 'Hokkai T8' (pollen parent), the leading variety in Japan, to improve its agronomic characteristics. The obtained progeny were subjected to performance test. 'Manten-Kirari' had no detectable rutinosidase isozymes in an in-gel detection assay and only 1/266 of the rutinosidase activity of 'Hokkai T8'. Dough prepared from 'Manten-Kirari' flour contained almost no hydrolyzed rutin, even 6 h after the addition of water, whereas the rutin in 'Hokkai T8' dough was completely hydrolyzed within 10 min. In a sensory evaluation of the flour from the two varieties, nearly all panelists detected strong bitterness in 'Hokkai T8', whereas no panelists reported bitterness in 'Manten-Kirari'. This is the first report to describe the breeding of a Tartary buckwheat cultivar with reduced rutin hydrolysis and no bitterness in the prepared flour. Notably, the agronomic characteristics of 'Manten-Kirari' were similar to those of 'Hokkai T8', which is the leading variety in Japan. Based on these characteristics, 'Manten-Kirari' is a promising for preparing non-bitter, rutin-rich foods.

Flavone C-glycosides from Lychnis senno and their antioxidative activity.

A new flavone C-glycoside, 5-O-acetyl-2"-alpha-rhamnopyranosylisovitexin (1), was isolated from the aerial parts of Lychnis senno Siebold et Zucc. (Family Caryophyllaceae), along with 2"-alpha-rhamnopyranosylisovitexin (2), 2"-a-rhamnopyranosylisoorientin (3) and isoorientin 3'-mehyl ether (4). All these compounds were isolated for the first time from L. senno and their antioxidative activity was analyzed by the 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical-scavenging method. Compound 3 showed moderate antioxidative activity.

Changes in polyphenolic content and radical-scavenging activity of sweet potato (Ipomoea batatas L.) during storage at optimal and low temperatures.

Polyphenolic content and radical-scavenging activities (RSA) of four sweet potato (Ipomoea batatas L.) cultivars were characterized after storage at optimal (15 degrees C) or low temperature (5 degrees C) for 0, 13, 26, and 37 days. The polyphenolic content increased during storage in three cultivars but not in 'Murasakimasari'. The change in 1,1-diphenyl-2-picrylhydrazyl radical-scavenging activity (DPPH-RSA) correlated very well with polyphenolic content. The increases in polyphenolics and the RSA in 'Benimasari' were significantly greater during storage at 5 degrees C than at 15 degrees C. The main polyphenolic components in all cultivars were chlorogenic acid (ChA) and 3,5-di-O-caffeoylquinic acid (3,5-diCQA). ChA level increased more at 5 degrees C than at 15 degrees C, whereas that of 3,5-diCQA was greater at 15 degrees C. Caffeoylquinic acids and RSA in 'Murasakimasari', which contains a large amount of anthocyanin in flesh tissue, were extremely high at the beginning of storage and remained nearly constant or decreased over time. A non-caffeoylquinic acid component that increased during storage, especially in 'J-Red' at 15 degrees C, was purified by successive chromatographic steps. The isolate was identified as caffeoyl sucrose [CSu, 6-O-caffeoyl-(beta- d-fructofuranosyl-(2-->1))-alpha-D-glucopyranoside] by fast atom bombardment-mass spectroscopy (FAB-MS), infrared spectroscopy (IR), and nuclear magnetic resonance spectroscopy (NMR). These results suggest that storage under cultivar-dependent, controlled temperature is one approach for increasing desirable physiologic function associated with RSA of polyphenolic compounds in sweet potato roots.

Carotenoids with a 5,6-dihydro-5,6-dihydroxy-beta-end group, from yellow sweet potato "Benimasari", Ipomoea batatas Lam.

A series of carotenoids with a 5,6-dihydro-5,6-dihydroxy-beta-end group, named ipomoeaxanthins A (1), B (2), C1 (3) and C2 (4) were isolated from the flesh of yellow sweet potato "Benimasari", Ipomoea batatas Lam. Their structures were determined to be (5R,6S,3'R)-5,6-dihydro-beta,beta-carotene-5,6,3'-triol (1), (5R,6S,5'R,6'S)-5,6,5',6'-tetrahydro-beta,beta-carotene-5,6,5'6'-tetrol (2), (5R,6S,5'R,8'R)-5',8'-epoxy-5,6,5',8'-tetrahydro-beta,beta-carotene-5,6-diol (3), and (5R,6S,5'R,8'S)-5',8'-epoxy-5,6,5',8'-tetrahydro-beta,beta-carotene-5,6-diol (4) by UV-Vis, NMR, MS and CD data.

[An adult case of bacterial meningitis caused by penicillin-resistant streptococcus pneumoniae].

We report a patient of bacterial meningitis caused by penicillin-resistant streptococcus pneumoniae (PRSP). A 50-year-old Japanese man was admitted after developing a fever and quickly falling into unconsciousness. Neurological examination showed slightly consciousness disturbance and meningeal irritation. A lumbar puncture yielded turbid spinal fluid, with increased cell count (411/mm3), protein (685 mg/dl) and IgG (60.3 mg/dl) but decreased glucose (1 mg/dl). Bacterial meningitis was diagnosed and aminobenzylpenicillin (ABPC) and cefotaxime (CTX) were administered immediately, but they were ineffective. Penicillin-resistant streptcoccus pneumoniae (PRSP) was detected in the blood and spinal fluid, so antibiotics were changed to panipenem/betamipron (PAPM/BP) and vancomycin (VCM) with marked efficacy. With the increase in PRSP patients and documented failure in treatment of pneumococcal meningitis with ABPC and CTX, the need for alternative antibiotic therapy is critical. We emphasize the importance of initial therapy with PAPM/BP and VCM in patients with bacterial meningitis from streptcoccus pneumoniae.

Identification and characterization of foliar polyphenolic composition in sweetpotato (Ipomoea batatas L.) genotypes.

Trials over two years were conducted using 1389 sweetpotato (Ipomoea batatas L.) genotypes collected from all over the world to characterize the polyphenolic composition in sweetpotato leaves. Wide variation was observed in relation to their total and individual leaf polyphenolic constituents. In all genotypes studied, the total polyphenol contents of sweetpotato leaf ranged from 1.42 to 17.1 g/100 g dry weight. The six different polyphenolic compounds were identified and quantified by NMR, FABMS, and RPHPLC analysis procedures. This is the first report of polyphenolic compositions in sweetpotato leaves. The relative levels of polyphenolic acids in sweetpotato leaves were as follows: 3,5-di-O-caffeoylquinic acid > 4,5-di-O-caffeoylquinic acid > chlorogenic acid (3-O-caffeoylquinic acid) > 3,4-di-O-caffeoylquinic acid > 3,4,5-tri-O-caffeoylquinic acid > caffeic acid. The highest 3,4,5-tri-O-caffeoylquinic acid and 4,5-di-O-caffeoylquinic acid occurred at 221 and 1183.30 mg/100 g dry weight, respectively.

Cerebrospinal fluid tau in dementia disorders: a large scale multicenter study by a Japanese study group.

A large scale multicenter study of cerebrospinal fluid (CSF) tau levels was conducted to determine the cut-off value, sensitivity and specificity for clinical usage as a biomarker of Alzheimer's disease (AD). Its use for early and differential diagnosis and the factors that increase CSF tau levels were also examined. CSF samples from a total of 1,031 subjects including 366 patients with AD, 168 patients with non-Alzheimer type dementia (NA), 316 patients with non-dementia neurological diseases (ND) and 181 normal controls (NC) were measured using ELISA for tau. The cut-off value of tau, 375 pg/ml, showed 59.1% sensitivity and 89.5% specificity for diagnosis of AD compared with the other groups. The tau levels were increased from the early to late stages of AD. Elevation of CSF tau in the non-tauopathy and tauopathy dementia groups, chronic and acute damage to the cerebrum, and meningeal disturbance were other factors that required attention for clinical practice. Measurement of CSF tau was useful as a biomarker for early and differential diagnosis of AD.