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

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

Determination of phytic acid and inositolphosphates in barley.

Phytic acid (PA) and lower inositolphosphates (InsP(n) ) is the main storage form of phosphorus in grains or seeds. The content of PA and InsP(n) in different varieties of barley was analyzed by capillary isotachophoresis and online-coupled capillary isotachophoresis with CZE. The electrolytes (in demineralized water) for the isotachophoretic analysis consisted of 10 mM HCl, 14 mM glycylglycine, and 0.1% 2-hydroxyethylcellulose (leading) and 10 mM citric acid (terminating). The optimized electrolytes for the online coupling isotachophoresis with zone electrophoresis analysis were mixtures of 5 mM HCl, 7 mM glycylglycine, and 0.1% 2-hydroxyethylcellulose (leading), 20 mM citric acid, 10 mM glycylglycine, and 0.1% 2-hydroxyethylcellulose (background) and 10 mM citric acid (terminating). PA and all studied InsP(n) were separated within 25 min and detected by a conductivity detector. Simple sample preparation (acidic extraction), sufficient sensitivity, speed of analysis, and low running cost are important attributes of the electrophoretic methods. The method was used for the determination of PA and InsP(n) in barley varieties within an ongoing research project.

Fusarium mycotoxins in various barley cultivars and their transfer into malt.

BACKGROUND: Fusarium toxins, secondary metabolites of toxinogenic Fusarium species, are found in a range of cereal grains. In this study the occurrence of the most commonest Fusarium toxins, namely nivalenol (NIV), deoxynivalenol (DON), deoxynivalenol-3-glucoside, fusarenon-X, 3- and 15-acetyldeoxynivalenol, HT-2 and T-2 toxins and zearalenone, in various barley cultivars harvested in 2005-2008 was monitored. The impact of weather, locality, fungicide treatment and barley cultivar (hulless or covered) on contamination was evaluated. The transfer of these mycotoxins into malt was assessed. RESULTS: The most prevalent toxin was DON, which was found in 83% of samples (maximum level 180 µg kg(-1)), while HT-2 was detected in 62% of samples (maximum level 716 µg kg(-1)). Using analysis of covariance, weather was found to be the key factor in all years (P < 0.001). A relationship between cultivar and contamination was confirmed only for HT-2 (P < 0.001) and T-2 (P = 0.037), with higher levels of these toxins being observed in hulless cultivars. With the exception of NIV (P = 0.008), no significant relationship was found between fungicide treatment and contamination. No distinct trend regarding DON levels in malt was found, with both decreases and increases occurring. CONCLUSION: The results show an inter-annual variation in mycotoxin occurrence in barley cultivars as well as differences in contamination of malt produced from fungicide-treated and untreated barley.

Fusarium Mycotoxins in Two Hulless Oat and Barley Cultivars Used for Food Purposes.

Hulless oats and hulless barley are highly valued for their excellent nutritional attributes and are increasingly being promoted in human nutrition. However, special attention should be paid to the risk of their contamination by Fusarium mycotoxins, as the rate of mycotoxin reduction during processing could be much lower than that for hulled cereals. In the present study, mycotoxin contamination of two cultivars, each of hulless oats and barley suitable for food purposes were studied in a 3-year field trial established in two contrasting environments. The contents of the mycotoxins regulated by law (deoxynivalenol and zearalenone) were low, and the present legal limits for their maximum content in unprocessed cereals were far from being exceeded. The mycotoxins most frequently occurring in hulless barley were enniatins (enniatin B, enniatin B1 and enniatin A1), beauvericin and nivalenol; hulless oats most frequently contained the HT-2 and T-2 toxins, beauvericin and enniatin B. The contents of enniatins and nivalenol were higher in barley than in oats. Close, positive relationships between the contents of the individual enniatins and between enniatins, beauvericin and nivalenol were observed, which implies that co-exposure could enhance the toxic potential of these mycotoxins through synergistic effects. The results highlight the need to pay more attention to the occurrence of enniatins, beauvericine and nivalenol in hulless oats and barley used for food purposes.

Phytochemical composition and ß-glucan content of barley genotypes from two different geographic origins for human health food production.

In the present study, 27 barley genotypes (Hordeum vulgare L.) grown in two geographic origins (Czech Republic and Spain) were analysed for their contents of ß-glucan, tocols and phenolic compounds (free and bound). The samples included hulled, hull-less and coloured genotypes. The results showed that concentrations of ß-glucan range from 2.40 to 7.42g/100g. Total tocol content of the barley samples ranged between 39.9 and 81.6µg/g. A total of 64 compounds were identified in the barley samples. These included 19 phenolic acids and aldehydes, 9 flavan 3-ols, 9 flavone glycosides, and 27 anthocyanins. The results showed a wide range of phenolic concentrations in the barley samples, highlighting the presence of considerable amounts of anthocyanins in purple barley genotypes. In synthesis, barley should be considered a good source of bioactive components, especially because of the broad spectrum of phytochemicals with potential health benefits besides the soluble fibre (ß-glucan).

Characterization and mapping of a putative laccase-like multicopper oxidase gene in the barley (Hordeum vulgare L.).

Laccases constitute a multi-gene family of multi-copper glycoproteins. The barley laccase-like multicopper oxidase (LMCO) gene structure, the DNA sequence polymorphism and putative protein have not yet been described. As part of the study of LMCO in cereals, we have characterized the genomic structure of the putative LMCO gene HvLac1 from the barley variety 'Morex' and mapped HvLac1 on chromosome 4H. The genomic sequence of the HvLac1 gene is 2646 bp long and covers 100% of the coding region. It contains four exons and three introns. In this study, we have described the HvLac1 gene nucleotide polymorphisms (In/Del) in 134 barley varieties. Initial characterization of the barley and rice LMCO and the phylogeny analysis indicate that a monocot LMCO family is composed of five members. There are two high pI isoforms of putative HvLac1 protein derived from two in frame translation start codons with 602aa or 592aa residues. Isoforms differ in their predicted subcellular localization and both isoforms are characterized on C-terminus by the presence of the KDEL-like motif, which contributes to the accumulation of soluble proteins in the endoplasmic reticulum. Our results suggest that this unique feature of HvLac1 could be important for their role in physiological processes.

Validation of the ß-amy1 transcription profiling assay and selection of reference genes suited for a RT-qPCR assay in developing barley caryopsis.

Reverse transcription coupled with real-time quantitative PCR (RT-qPCR) is a frequently used method for gene expression profiling. Reference genes (RGs) are commonly employed to normalize gene expression data. A limited information exist on the gene expression and profiling in developing barley caryopsis. Expression stability was assessed by measuring the cycle threshold (Ct) range and applying both the GeNorm (pair-wise comparison of geometric means) and Normfinder (model-based approach) principles for the calculation. Here, we have identified a set of four RGs suitable for studying gene expression in the developing barley caryopsis. These encode the proteins GAPDH, HSP90, HSP70 and ubiquitin. We found a correlation between the frequency of occurrence of a transcript in silico and its suitability as an RG. This set of RGs was tested by comparing the normalized level of ß-amylase (ß-amy1) transcript with directly measured quantities of the BMY1 gene product in the developing barley caryopsis. This panel of genes could be used for other gene expression studies, as well as to optimize ß-amy1 analysis for study of the impact of ß-amy1 expression upon barley end-use quality.

Antioxidant vitamins in barley green biomass.

Two malting hulled varieties (Sebastian, Malz) and one nonmalting hull-less variety (AF Lucius) were used to assess vitamins C and E in the green biomass of young plants of spring barley ( Hordeum vulgare L.) in three stages of growth and development (BBCH 29, 31, 32-33). The samples from sampling I (BBCH 29) had statistically significantly higher vitamin C content and vitamin E activity compared to sampling I (BBCH 31). The highest average vitamin content was determined in the malting variety Sebastian (vitamin C, 520 mg 100 g(-1) DM; vitamin E, 73.06 mg kg(-1) DM) compared to the varieties Malz (501 mg 100 g(-1) DM; 61.84 mg kg(-1) DM) and AF Lucius (508 mg 100 g(-1) DM; 67.81 mg 100 g(-1) DM). The locality Kromeríz (Czech Republic, CR), with vitamin C and E contents of 524 mg 100 g(-1) DM and 68.74 mg kg(-1) DM, respectively, proved to be more suitable for growing green biomass compared to the locality Zabcice (CR) (content of vitamins C and E, 477 mg 100 g(-1) DM and 66.39 mg kg(-1) DM, respectively). During the research period (2005-2007), it was determined that the green mass of young plants of spring barley was a significant source of vitamins C and E in the growth stage BBCH 29; in later samplings (BBCH 32-33) the vitamin levels dropped (by as much as 48%). These vitamins are important antioxidants for human health. Therefore, "green barley" can be recommended for the preparation of natural dietary supplements and is preferred to synthetic vitamin preparations.