Effects of Growth Conditions and Cultivar on the Content and Physiochemical Properties of Arabinoxylan in Barley.

The present study aims to evaluate the effect of the growth conditions and the cultivar on the total and water-extractable (W-E) arabinoxylan (AX) in barley. For this purpose, nine barley varieties from two different years were analyzed. The total AX content ranged from 5.97 to 8.98 wt % d.m., while the W-E AX ranged from 0.06 to 0.35 wt % d.m. The W-E AX molecular properties were characterized by high-pressure size exclusion chromatography (HPSEC)-triple detector array (TDA). The molecular weight was between 2.3 × 105 and 12.6 × 105 Da, the polydispersity was between moderate and broad (1.1 < Mw/Mn < 4.3), and the conformation was a stiff semiflexible coil (0.5 < α < 1.3). The results indicate that the year influences the content of total AX and W-E AX and some molecular characteristics of W-E AX, such as its polydispersity and its conformation. Finally, the results demonstrated that the W-E AX can be used as an index of the malting attitude of barley because it positively correlates with germinative energy and kernel dimension.

Free and Bound Phenolic Compound Content and Antioxidant Activity of Different Cultivated Blue Highland Barley Varieties from the Qinghai-Tibet Plateau.

In this study, the polyphenols composition and antioxidant properties of 12 blue highland barley varieties planted on the Qinghai-Tibet Plateau area were measured. The contents of the free, bound and total phenolic acids varied between 166.20-237.60, 170.10-240.75 and 336.29-453.94 mg of gallic acid equivalents per 100 g of dry weight (DW) blue highland barley grains, while the free and bound phenolic acids accounted for 50.09% and 49.91% of the total phenolic acids, respectively. The contents of the free, bound and total flavones varied among 20.61-25.59, 14.91-22.38 and 37.91-47.98 mg of catechin equivalents per 100 g of dry weight (DW) of blue highland barley grains, while the free and bound flavones accounted for 55.90% and 44.10% of the total flavones, respectively. The prominent phenolic compounds in the blue hulless barley grains were gallic acid, benzoic acid, syringic acid, 4-coumaric acid, naringenin, hesperidin, rutin, (+)-catechin and quercetin. Among these, protocatechuic acid, chlorogenic acid and (+)-catechin were the major phenolic compounds in the free phenolics extract. The most abundant bound phenolics were gallic acid, benzoic acid, syringic acid, 4-coumaric acid, benzoic acid, dimethoxybenzoic acid, naringenin, hesperidin, quercetin and rutin. The average contribution of the bound phenolic extract to the DPPH• free radical scavenging capacity was higher than 86%, that of free phenolic extract to the ABTS•+ free radical scavenging capacity was higher than 79%, and that of free phenolic (53%) to the FRAP antioxidant activity was equivalent to that of the bound phenol extract (47%). In addition, the planting environment exerts a very important influence on the polyphenol composition, content and antioxidant activity of blue highland barley. The correlation analysis showed that 2,4-hydroxybenzoic acid and protocatechuic acid were the main contributors to the DPPH• and ABTS•+ free radical scavenging capacity in the free phenolic extract, while chlorogenic acid, vanillic acid, ferulic acid and quercetin were the main contributors to the free radical scavenging capacity in the bound phenol extract. The study results show that the blue highland barley grains have rich phenolic compounds and high antioxidant activity, as well as significant varietal differences. The free and bound phenolic extracts in the blue hulless barley grains have an equivalent proportion in the total phenol, and co-exist in two forms. They can be used as a potential valuable source of natural antioxidants, and can aid in enhancing the development and daily consumption of foods relating to blue highland barley.

Genetic Diversity of Individual Phenolic Acids in Barley and Their Correlation with Barley Malt Quality.

Phenolic acids have been quite extensively studied in food science research because of their antioxidative effect. In this study, the genotypic difference and genetic control of phenolic acids, and their correlation with malt quality, were investigated in barley. Ferulic acid (FA) and p-coumaric acid (p-CA) were identified as two main phenolic acids, showing wide variations among 68 barley genotypes. The mean content of FA and p-CA were 2.15 µg g(-1) and 1.10 µg g(-1) in grains and 4.07 µg g(-1) and 1.44 µg g(-1) in malt, respectively. After malting, FA and p-CA were increased significantly in 55 and 37 genotypes and were reduced in 2 and 14 genotypes, respectively. Both malt FA and p-CA were positively correlated with soluble N content and Kolbach index and negatively correlated with malt extract and viscosity. The results indicated that the effect of malting on the change of an individual phenolic acid is genotype independent. Association mapping identified that 8 markers on Chromosomes 1H, 2H, 4H, and 7H are associated with grain p-CA and 4 markers on Chromosomes 3H and 7H are linked with grain FA. However, only a single marker on Chromosome 3H was found to be associated with malt FA. Moreover, a lack of overlapping markers between grain and malt indicated the genetic diversity of phenolic acids in barley grain and malt. Our results strengthen the understanding of phenolic acids in barley and their responses to the malting process.

Analysis of oligomer proanthocyanidins in different barley genotypes using high-performance liquid chromatography-fluorescence detection-mass spectrometry and near-infrared methodologies.

Proanthocyanidins are a class of polyphenols present in many foodstuffs (i.e., tea, cocoa, berries, etc.) that may reduce the risk of several chronic diseases. Barley, with sorghum, rice, and wheat, are the only cereals that contain these compounds. Because of that, two barley genotypes, named waxy and non-waxy, were analyzed by normal-phase high-performance liquid chromatography-fluorescence detection-mass spectrometry (NP-HPLC-FLD-MS). Total proanthocyanidin content ranged between 293.2 and 652.6 µg/g of flour. Waxy samples reported the highest content (p < 0.05) of proanthocyanidins. Dimer compounds were the principal proanthocyanidin constituents of barley samples. Moreover, the possibility to use near-infrared (NIR) spectroscopy as a rapid method to discriminate between waxy and non-waxy samples and to predict quantitatively proanthocyanidins in barley samples was evaluated. Partial least squares (PLS) models were built to predict the proanthocyanidin constituent, obtaining determination coefficients (R(2)) ranging from 0.92 to 0.97, in test set validation. Because of that, this study highlights that NIR spectroscopy technology with multivariate calibration analysis could be successfully applied as a rapid method to determine proanthocyanidin content in barley.

[Determination of the content of the main components of flavonoids compounds in raw malt, torrefied malt and ustulate malt].

OBJECTIVE: To determine the content of Catechin, Myricetin, Quercetin and Kaempferol in barley grain, raw malt, torrefied malt and ustulate malt based on different barley cultivars. METHODS: HPLC method was used. Analysis was performed on Agilent ZORBAXSB-C18 (150 mm x 4. 6 mm, 3.5 microm) column with acetonitrile-0.1% acetic acid as mobile phase. The detection wavelength was 280 nm, flow rate was 0.8 mL/min, and the column temperature was 30 degrees C. RESULTS: Catechin was the main component of barley seeds and its processed products. Slight reduction of catechin was observed in processed and sprouting seeds. Sprouting significantly increased the content of myricetin. Both barley seeds and the processed products were lack of quercetin. The amounts of kaempferol in seed were higher than that in barley grain, but similar to that in ustulate malt. CONCLUSION: The content of flavonoids in raw malt and torrefied malt are significantly affected by sprouting and processing, and significance differences are presented among different varieties.

Microspore embryogenesis: assignment of genes to embryo formation and green vs. albino plant production.

Plant microspores can be reprogrammed from their normal pollen development to an embryogenic route in a process termed microspore embryogenesis or androgenesis. Stress treatment has a critical role in this process, inducing the dedifferentiation of microspores and conditioning the following androgenic response. In this study, we have used three barley doubled haploid lines with similar genetic background but different androgenic response. The Barley1 GeneChip was used for transcriptome comparison of these lines after mannitol stress treatment, allowing the identification of 213 differentially expressed genes. Most of these genes belong to the functional categories "cell rescue, defense, and virulence"; "metabolism"; "transcription"; and "transport". These genes were grouped into clusters according to their expression profiles among lines. A principal component analysis allowed us to associate specific gene expression clusters to phenotypic variables. Genes associated with the ability of microspores to divide and form embryos were mainly involved in changes in the structure and function of membranes, efficient use of available energy sources, and cell fate. Genes related to stress response, transcription and translation regulation, and degradation of pollen-specific proteins were associated with green plant production, while expression of genes related to plastid development was associated with albino plant regeneration.

An aluminum-activated citrate transporter in barley.

Soluble ionic aluminum (Al) inhibits root growth and reduces crop production on acid soils. Al-resistant cultivars of barley (Hordeum vulgare L.) detoxify Al by secreting citrate from the roots, but the responsible gene has not been identified yet. Here, we identified a gene (HvAACT1) responsible for the Al-activated citrate secretion by fine mapping combined with microarray analysis, using an Al-resistant cultivar, Murasakimochi, and an Al-sensitive cultivar, Morex. This gene belongs to the multidrug and toxic compound extrusion (MATE) family and was constitutively expressed mainly in the roots of the Al-resistant barley cultivar. Heterologous expression of HvAACT1 in Xenopus oocytes showed efflux activity for (14)C-labeled citrate, but not for malate. Two-electrode voltage clamp analysis also showed transport activity of citrate in the HvAACT1-expressing oocytes in the presence of Al. Overexpression of this gene in tobacco enhanced citrate secretion and Al resistance compared with the wild-type plants. Transiently expressed green fluorescent protein-tagged HvAACT1 was localized at the plasma membrane of the onion epidermal cells, and immunostaining showed that HvAACT1 was localized in the epidermal cells of the barley root tips. A good correlation was found between the expression of HvAACT1 and citrate secretion in 10 barley cultivars differing in Al resistance. Taken together, our results demonstrate that HvAACT1 is an Al-activated citrate transporter responsible for Al resistance in barley.

Wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) multiple inositol polyphosphate phosphatases (MINPPs) are phytases expressed during grain filling and germination.

At present, little is known about the phytases of plant seeds in spite of the fact that this group of enzymes is the primary determinant for the utilization of the major phosphate storage compound in seeds, phytic acid. We report the cloning and characterization of complementary DNAs (cDNAs) encoding one of the groups of enzymes with phytase activity, the multiple inositol phosphate phosphatases (MINPPs). Four wheat cDNAs (TaPhyIIa1, TaPhyIIa2, TaPhyIIb and TaPhyIIc) and three barley cDNAs (HvPhyIIa1, HvPhyIIa2 and HvPhyIIb) were isolated. The open reading frames ranged from 1548 to 1554 bp and the level of homology between the barley and wheat proteins ranged from 90.5% to 91.9%. All cDNAs contained an N-terminal signal peptide encoding sequence, and a KDEL-like sequence, KTEL, was present at the C-terminal, indicating that the enzyme was targeted to and retained within the endoplasmic reticulum. Expression of TaPhyIIa2 and HvPhyIIb in Escherichia coli revealed that the MINPPs possessed a significant phytase activity with narrow substrate specificity for phytate. The pH and temperature optima for both enzymes were pH 4.5 and 65 degrees C, respectively, and the K(m) values for phytate were 246 and 334 microm for the wheat and barley recombinant enzymes, respectively. The enzymes were inhibited by several metal ions, in particular copper and zinc. The cDNAs showed significantly different temporal and tissue-specific expression patterns during seed development and germination. With the exception of TaPhyIIb, the cDNAs were present during late seed development and germination. We conclude that MINPPs constitute a significant part of the endogenous phytase potential of the developing and germinating barley and wheat seeds.

Elemental fingerprint analysis of barley (Hordeum vulgare) using inductively coupled plasma mass spectrometry, isotope-ratio mass spectrometry, and multivariate statistics.

Inductively coupled plasma mass spectrometry (ICP-MS) and isotope-ratio mass spectrometry (IR-MS) have been used to examine the multi-elemental composition and (15)N/(14)N and (13)C/(12)C isotope ratios of three spring barley (Hordeum vulgare) genotypes (Orthega, Barke, and Bartok) grown in three typical Danish agricultural soils (North Jutland, West Jutland, and East Zealand) differing in soil fertility. The aim of the study was to examine whether it was possible to generate a unique elemental fingerprint of individual barley genotypes irrespective of the elemental imprint plants had received from soils differing in fertility and agricultural practice. Multivariate statistics were used to analyze the elemental fingerprints of the barley genotypes at different times during a full growing season from early tillering to full maturity of the barley grains. Initially, 36 elements were analyzed in the plant samples but this number was subsequently reduced to 15 elements: B, Ba, C, Ca, Cu, Fe, K, Mg, Mn, N, Na, P, S, Sr, and Zn. These elements exceeded the limit of detection ( LOD) for all genotypes, soil types, and plant growth stages and for these elements the accuracy was better than 90% compared with apple leaf certified reference material (CRM). Principal component analysis (PCA) separated multi-elemental data in accordance with soil type when plants of similar physiological age were compared, whereas this separation disappeared if plants of all ages were compared simultaneously. Isotope ratios (delta(15)N) of plants also proved to be a highly accurate property for classification of samples according to soil type. In contrast, the differences in delta(13)C were too small to enable such classification. The differences in delta(15)N among soils were so pronounced that separation of samples according to the physiological age of plants became redundant. However, delta(15)N and the multi-elemental analysis revealed no differences between the three barley genotypes, indicating that the influence of soil chemistry and possibly also climate and agricultural practice was too large to allow an unique elemental fingerprint for the genotypes. This finding was substantiated by analyzing the multi-elemental composition of grain from two additional genotypes (Otira and Barthos) grown at the north and east locations, respectively. PCA showed not only that the elemental fingerprints of these two genotypes were similar to those of the others, but also that the soil in which the plant had been growing could be accurately predicted on the basis of the PCA scores from the genotypes Orthega, Barke, and Bartok. Similar conclusions could be drawn using delta(15)N data.

[Effect of zinc fertilization on cadmium uptake and accumulation in two barley (Hordeum vulgare) cultivars].

A pot experiment was carried out in a greenhouse to investigate the interactive effects of Zn-Cd on the growth and the uptake of Cd and Zn by two barley genotypes (Sahara and Clipper). The results showed that under the conditions of this experiment, adding Cd and Zn had no significant effect on the shoot biomass of either cultivars, but applying Zn tended to reduce the root biomass of both cultivars. With the amount of less than 20 mg.kg-1, Zn addition did not affect Cd concentration in plant tissues; while at 40 mg.kg-1, it decrease Cd concentrations significantly in plant tissues of both cultivars. Total Cd uptake by both cultivars decreased with increasing in Zn application, mainly due to the decrease in root biomass. The two genotypes were significantly different in Zn uptake, but this difference did not affect Cd uptake. Cd concentration in roots of Zn-efficient cultivar Sahara was lower than that of Zn-inefficient cultivar Clipper.