The combined use of hull-less barley flour and xylanase as a strategy for wheat/hull-less barley flour breads with increased arabinoxylan and (1→3,1→4)-β-D-glucan levels

Bread-making with a composite flour (CF) consisting of 60% wheat flour (WF) and 40% hull-less barley flour, increased the total and soluble (1→3,1→4)-β-D-glucan and total arabinoxylan (AX) contents of dough and bread samples, but decreased the specific bread loaf volume. A xylanase insensitive to inhibition by Triticum aestivum L. xylanase inhibitor (TAXI) and xylanase inhibiting protein (XIP), increased loaf volume by 8.8 and 20.1% for WF and CF breads, respectively. Xylanase addition not only markedly improved loaf volume of CF bread, but also increased the soluble AX content of the WF and CF dough and bread samples because of conversion of water-unextractable AX into soluble AX. The xylanase had no impact on the extractability and molecular weight of (1→3,1→4)-β-D-glucan, but (1→3,1→4)-β-D-glucan was degraded during bread-making probably because of endogenous β-glucanase activity. Taken together, the results clearly show that the combined use of hull-less barley flour and a xylanase active during bread making, lead to palatable breads with high total and soluble AX and (1→3,1→4)-β-D-glucan contents. The sum of total AX and (1→3,1→4)-β-D-glucan was 1.70% for WF bread and 3.06% for CF bread, while the sum of soluble AX and (1→3,1→4)-β-D-glucan was 0.49 and 1.41% for control WF and CF xylanase supplemented breads, respectively.     

Distribution of (1-3)(1-4)-β-d-glucans in kernels of selected cultivars of naked and hulled barley

The objective of this study was to determine the distribution of (1-3)(1-4)-β-d-glucans in the kernels of three high-glucan lines of naked barley (STH 4561, STH 4671 and STH 4676), a low-glucan line (STH 4572), and two low-glucan comparative cultivars (naked – Rastik, and hulled – Stratus). The content of (1-3)(1-4)-β-d-glucans assayed with the enzymatic method varied within the range from 4.04 to 5.71% dry matter basis. Microspectrophotometric analysis revealed significant differentiation in the structure of the kernels and in the distribution of (1-3)(1-4)-β-d-glucans; it also indicated a necessity of applying such processing methods as are appropriate to the distribution of functional components. The distribution of functional components in the high-glucan lines of naked barley makes them ideal for utilization both in the milling technology and in the production of grits and flakes.     

Influence of growth temperature on content,viscosity and relative molecular weight of water-soluble β-glucans in barley (Hordeum vulgare L.)

β-Glucan content and viscosity of water-soluble β-glucans have a considerable impact on the digestion of barley. Eight different 2-row barley (Hordeum vulgare L.) cultivars were grown in controlled environment chambers at five different temperatures until maturity. The samples were pearled, milled and analysed for their content of total, insoluble and soluble β-glucan. The water-soluble fraction was extracted at 37 °C, subjected to amylase treatment and freeze-dried. Water-soluble crude β-glucans were solubilised in distilled water, analysed for viscosity and their purity was checked by nuclear magnetic resonance. Molecular weights were profiled by size exclusion chromatography with RI detection. The content of total β-glucan varied from 4.0% to 7.4%, and was significantly affected by the growth temperature. An interaction between cultivar and growth temperature was observed for the total β-glucan content. The extractability was significantly affected by growth temperature, as there was recorded an increasing amount of water-soluble β-glucan with increasing growth temperature. Both the viscosity and the molecular weight of the water-soluble β-glucans increased with the growth temperature.     

Do barley and wheat (bread and durum) differ in grain weight stability through seasons and water-nitrogen treatments in a Mediterranean location?

Under Mediterranean environments, farmers usually prefer to sow barley rather than wheat as it is generally believed that barley yields more under stressful conditions. As terminal stresses such as high temperature and water are common constraints in Mediterranean regions, higher grain weight stability may confer a clear advantage in order to maintain higher yields. The objective of the present study was to compare the stability in terms of grain weight and its components for barley, bread wheat, and durum wheat, exploring a wide range of nitrogen and water availabilities in experiments conducted in a Mediterranean region. Grain weight ranged from 23.8 to 47.7 mg grain⁻¹, being higher for durum wheat than barley and bread wheat. Durum wheat presented higher variability both in maximum grain filling rate and duration of grain filling period than bread wheat or barley. The three species responded similarly in terms of grain nitrogen content to changes in the environmental conditions explored. It is concluded that in terms of grain weight barley is as stable as bread wheat. However, durum wheat presented a lower stability than barley and bread wheat.     

Determination of (1→3),(1→4)-β-D-Glucanase Activity by a Calcofluor-Flow Injection Analysis Method

A new methodology for the determination of (1→3),(1→4)-β-d-glucanase activity has been developed. The concentration decay curves corresponding to the depolymerisation of high molecular weight barley (1→3),(1→4)-β-d-glucan by pure (1→3),(1→4)-β-d-glucanase (E.C. 3.2.1.73) fromBacillus subtilisand by crude (1→3),(1→4)-β-d-glucanase from different malts were monitored by the Calcofluor-FIA method. In all cases, the high molecular weight (17Instituto de Agroquı́mica y Tecnologı́a de Alimentos (CSIC)rarr;3),(1→4)-β-d-glucan decay curves fitted very well to an empirical formula describing the change in substrate concentration with time. The curves possess an inflexion point at which the depolymerisation rate of the substrate reaches a maximum. This maximum depolymerisation rate correlates with the initial concentrations of enzyme and substrate,E_oandS_o, and the enzyme kinetic constantsV_mandK_mthrough a hyperbola similar to that of Michaelis-Menten. TheK_mdetermined forB. subtilisβ-glucanase was rather low, about 0·99 g β-glucan/l, when compared with those corresponding to (1→3),(1→4)-β-d-glucanase from different malts, which were, in turn, practically identical at about 2·92 g β-glucan/l. Experiments with barley (1→3),(1→4)-β-d-glucans of different high initial molecular weights showed that initial molecular weight had no influence on the kinetics. Thus, this new methodology permits the determination of (1→3),(1→4)-β-d-glucanase activity in a direct way, i.e. the amount of (1→3),(1→4)-β-d-glucan degraded per amount of enzyme (or malt) per unit of time. Moreover, since it is insensitive to the initial molecular weight of the substrate, it seems to be well-suited for inter-laboratory comparisons of (1→3),(1→4)-β-d-glucanase activities.     

High (1→3,1→4)-β-Glucan Barley Fractions in Bread Making and their Effects on Human Glycemic Response

Barley flour (BF) from whole naked grain and two (1→3,1→4)-β-glucan-enriched fractions, a sieved fraction (SF) and a water-extracted fraction (WF), were produced and mixed with bread wheat flour (BW), for bread-making quality evaluation. Bread was baked in a pilot plant and analysed for sensory properties, proximate composition and (1→3,1→4)-β-glucan content. Four kinds of bread were produced from different mixtures of barley ingredients and bread wheat flour: a 100% BW ((1→3,1→4)-β-glucan content: total, 0·1%; soluble, 0·1%); a 50% BW and 50% BF (2·4%; 2·0%); a 50% BW and 50% SF (4·2%; 2·8%); an 80% BW and 20% WF (6·3%; 5·7%). Eight adults were fed test meals of each of the four breads, containing the same amount (50 g) of available carbohydrate, and glycemic indices calculated from finger-prick capillary blood samples. A linear decrease in glycemic index was found for increasing (1→3,1→4)-β-glucan content. The 20% WF bread had a 28% lower glycemic index than the plain BW and also showed the best scores for sensory attributes. This research confirms the effectiveness of viscous (1→3,1→4)-β-glucan in reducing postprandial blood glucose levels, even in foods with a high glycemic index. The enrichment technique, and water extraction/freeze-drying technique, could enable the use of barley as a source of a high-value fibre for reducing the glycemic index of traditional wheat-based foods such as bread, without negatively affecting their sensory characteristics.     

Decomposition of (1–3,1–4)-β-Glucan and Expression of the (1–3,1–4) -β-Glucanase Gene in Rice Stems during Ripening

Abstract

To elucidate the possible participation of hemicellulose decomposition in lodging resistance, we studied the change of hemicellulose and cellulose content in the stems of rice during the ripening stage by methylation analysis and the expression of related genes by Northern blotting. In the rice stem in ripening stage, content of (1-3,1-4)-β-glucan, a component of hemicellulose, decreased markedly although the content of arabinoxylan, a major component of hemicellulose, and cellulose showed little change during the same growth period. On the other hand, expression of the Gns 1 gene, which may encode (1-3,1-4) -β-glucanase that catalyzes the degradation of (1-3,14) -β-glucan, increased sharply in the stem. The mechanism of decomposition of (1-3,1-4) -β-glucan in rice stem and the possible association with lodging resistance is discussed.     

Varietal Differences in Cell Wall β-(1→3),(1→4)-Glucan and Nonstructural Carbohydrate in Rice Stems during the Grain Filling Stage

Abstract

The contribution of cell wall components and nonstructural carbohydrate (NSC) to grain filling in rice (Oryza sativa L.) was clarified by investigating the differences in the dynamics of hemicellulose, sugar composition of hemicellulose, β-(1→3),(1→4)-glucan, and NSC among cultivars with different grain filling capacities. This investigation was performed using the stems of standard, high yield and low harvest index (HI) cultivars. Hemicellulose concentration in stems tended to decrease slightly during the grain filling stage. This decrease was attributed to a decrease in β-(1→3),(1→4)-glucan concentration, which was detected as a decrease in glucose composition of hemicellulose in the stems during the grain filling stage. The rate of decrease and decrease in the amount of β-(1→3),(1→4)-glucan in the stems differed among the cultivars. These were higher in high yield and high HI cultivars than in relatively low yield and low HI cultivars. Moreover, a positive correlation was observed between the rate of decrease in β-(1→3),(1→4)-glucan and NSC, indicating similarities in the dynamics of β-(1→3),(1→4)-glucan and NSC among the cultivars. When the top half of panicle was removed, β-(1→3),(1→4)-glucan and NSC concentrations in the culm and leaf sheath did not decrease during the grain filling stage. Therefore, the β-(1→3),(1→4)-glucan in stems might be one of the sources that supply substrate to panicle as well as NSC.     

In vitro fermentation kinetics and end-products of cereal arabinoxylans and (1,3;1,4)-β-glucans by porcine faeces

Purified and semi-purified polysaccharides characteristic of cereals were fermented in vitro with a pig faecal inoculum, using the cumulative gas production technique, to examine the kinetics and end-products of fermentation after 48 h. It was shown that arabinoxylan and mixed linkage (1,3;1,4) β-glucan were rapidly fermented if soluble, while less soluble substrates (insoluble arabinoxylan, maize and wheat starch granules, and bacterial cellulose) were more slowly fermented. Relevant monosaccharides were fermented at very similar rates to soluble polymeric arabinoxylan and β-glucan, showing that depolymerisation was not a limiting step, in contrast to some previous studies. Bacterial cellulose is shown to be a useful model substrate for fermentation of plant cellulose which is difficult to obtain without harsh chemical treatments. Fermentation end-products were related to kinetics, with slow carbohydrate fermentation resulting in increased protein fermentation. Ratios of short-chain fatty acid products were similar for all arabinoxylan and β-glucan substrates.     

Synthesis of (3S,3′S)- and meso-Stereoisomers of Alloxanthin and Determination of Absolute Configuration of Alloxanthin Isolated from Aquatic Animals

In order to determine the absolute configuration of naturally occurring alloxanthin, a HPLC analytical method for three stereoisomers 1a–c was established by using a chiral column. Two authentic samples, (3S,3′S)- and meso-stereoisomers 1b and 1c, were chemically synthesized according to the method previously developed for (3R,3′R)-alloxanthin (1a). Application of this method to various alloxanthin specimens of aquatic animals demonstrated that those isolated from shellfishes, tunicates, and crucian carp are identical with (3R,3′R)-stereoisomer 1a, and unexpectedly those from lake shrimp, catfish, biwa goby, and biwa trout are mixtures of three stereoisomers of 1a–c.     

The Effect of Sulfated (1→3)-α-L-Fucan from the Brown Alga Saccharina cichorioides Miyabe on Resveratrol-Induced Apoptosis in Colon Carcinoma Cells

Accumulating data clearly indicate that the induction of apoptosis by nontoxic natural compounds is a potent defense against the development and progression of many malignancies, including colon cancer. Resveratrol and the fucoidans have been shown to possess potent anti-tumor activity in vitro and in vivo. The aim of the present study was to examine whether the combination of a fucoidan from the brown alga Saccharina cichorioides Miyabe and resveratrol would be an effective preventive and/or therapeutic strategy against colon cancer. Based on NMR spectroscopy and MALDI-TOF analysis, the fucoidan isolated and purified from Saccharina cichorioides Miyabe was (1→3)-α-L-fucan with sulfate groups at C2 and C4 of the α-L-fucopyranose residues. The fucoidan enhanced the antiproliferative activity of resveratrol at nontoxic doses and facilitated resveratrol-induced apoptosis in the HCT 116 human colon cancer cell line. Apoptosis was realized by the activation of initiator caspase-9 and effector caspase-7 and -3, followed by the cleavage of PARP. Furthermore, significant inhibition of HCT 116 colony formation was associated with the sensitization of cells to resveratrol by the fucoidan. Taken together, these results demonstrate that the combination of the algal fucoidan with resveratrol may provide a potential therapy against human colon cancer.     

Accumulation of mixed linkage (1 → 3) (1 → 4)-β-d-glucan during grain filling in barley: A vibrational spectroscopy study

The accumulation of mixed linkage barley (1 → 3) (1 → 4)-β-d-glucan (BG) during grain filling at eight stages was studied using standard reference methods and infrared spectroscopy. Two mutant barley genotypes having higher (starch mutant lys5f) and lower (high lysine mutant lys3a) BG content than the normal control Cork were studied. The Cork and lys3a genotypes showed a linear BG accumulation throughout the grain filling to reach a maximum of approximately 6 and 4% BG (w/w) dry matter, respectively. However, lys5f mutant exhibited an exponential increase in BG synthesis to a maximum of approximately 18% BG (w/w) dry matter 30 days after flowering (DAF), seemingly compensating for a decreased synthesis of starch.     

Inheritance of C3―C4 Intermediate Photosynthesis in Reciprocal Hybrids Between Moricandia Arvensis (C3―C4) and Brassica Oleracea (C3) That Differ in Their Genome Constitution

Abstract

To Elucidate The Genetic Mechanisms Underlying C₃―C₄ intermediate Photosynthesis, We investigated The Structural and Photosynthetic Characteristics of Leaves of Reciprocal Hybrids Between The C₃―C₄ intermediate Species Moricandia Arvensis (L.) Dc. (Mama) and The C₃ Species Brassica Oleracea L. (Cabbage; Cc), Which Differ in Genome Constitution. Moricandia Arvensis Bundle Sheath (Bs) Cells included Many Centripetally Located Chloroplasts and Mitochondria, Whereas Those of Cabbage Had Few Organelles. Hybrid Leaves Were Structurally intermediate Between Those of The Parents and Showed Stronger intermediate C₃―C₄ Features As The Proportion of The Ma Genome increased. The P-Protein of Glycine Decarboxylase (Gdc) Was Confined Mainly To Bs Mitochondria in M. Arvensis, But Accumulated More in The Mesophyll (M) of Cabbage. in The Hybrids, The Accumulation of Gdc in Bs Cells increased With An increasing Ma:C Ratio. Hybrids Exhibited Gradients in Structural and Biochemical Features, Even in Reciprocal Crosses. The Co₂ Compensation Point of Reciprocal Hybrids With High Ma:C Ratios Was Lower Than That of Cabbage But Higher Than That of M. Arvensis. Thus, The Structural and Biochemical Features in Hybrid Leaves Reduced Photorespiration. Moricandia Arvensis Had A Higher Photosynthetic Rate Than Cabbage, But The Photosynthetic Rates of Hybrids Were intermediate Between Those of The Parents Or Comparable To That of M. Arvensis. Our Results Demonstrate That The C₃―C₄ intermediate Characteristics Are inherited Based On The Ratio of The Parent Genomes, and That There Is No Evidence of Cytoplasmic inheritance in These Characteristics.     

A nucleotide substitution at the 5′ splice site of intron 1 of rice HEADING DATE 1(HD1) gene homolog in foxtail millet,broadly found in landraces from Europe and Asia

We investigated genetic variation of a rice HEADING DATE 1(HD1) homolog in foxtail millet.First, we searched for a rice HD1 homolog in a foxtail millet genome sequence and designed primers to amplify the entire coding sequence of the gene. We compared full HD1 gene sequences of 11 accessions(including Yugu 1, a Chinese cultivar used for genome sequencing) from various regions in Europe and Asia, found a nucleotide substitution at a putative splice site of intron 1, and designated the accessions with the nucleotide substitution as carrying a splicing variant. We verified by RT-PCR that this single nucleotide substitution causes aberrant splicing of intron 1. We investigated the geographical distribution of the splicing variant in 480 accessions of foxtail millet from various regions of Europe and Asia and part of Africa by d CAPS and found that the splicing variant is broadly distributed in Europe and Asia. Differences of heading times between accessions with wild type allele of the HD1 gene and those with the splicing variant allele were unclear. We also investigated variation in 13 accessions of ssp. viridis, the wild ancestor, and the results suggested that the wild type is predominant in the wild ancestor.     

pH-, Temperature- and Time-dependent Activities of Endogenous Endo-β-D-Xylanase, β-D-Xylosidase and α-L-Arabinofuranosidase in Extracts from Ungerminated Rye (Secale cereale L.) Grain

Activities of endogenous β-D-xylosidase (EC.3.2.1.37), α-L-arabinofuranosidase (EC. 3.2.1.55) and endo-β-D-xylanase (EC.3.2.1.8) were quantified in extracts from ungerminated rye (Secale cereale Lvar. Amando) grain. pH- and temperature optimum and stability of the unpurified enzymes were examined. The activity of β-xylosidase and α-arabinofuranosidase against p-nitrophenyl-glycosides was 180 and 346 pkatal/g grain, respectively (pH 4·5; 30 °C) and that of the endo-xylanase against RBB-xylan was 11 pkatal/g grain (pH 4·5; 40 °C). The pH optimum of each of the enzymes was 4·5, which is similar to the pH of a rye dough. The temperature optima for the enzymes were 40 °C (endo-xylanase), 70 °C (β-xylosidase) and 60 °C (α-arabinofuranosidase), respectively. Sodium chloride (0·5–3·0%, w/v) had no effect on enzyme activities. The enzymes were relatively stable at pH 4·5 and room temperature for at least 24 h. The enzymes showed no significant decrease in activity when extracts were incubated at pH 4·5 and 30–40 °C for 80–120 min. Incubation at temperatures higher than 40 °C resulted in a significant decrease in activity. The rate of hydrolysis of the respective p -nitrophenyl glycosides and RBB-xylan was high under conditions typical for the rye dough production stages but decreased at temperatures typically encountered in the baking process.