Browsing by Subject "BARLEY"

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  • Chang, Wei; Jääskeläinen, Marko; Li, Song-ping; Schulman, Alan H. (2013)
  • Wang, Yu-Jie; Yang, Lingxi; Sontag-Strohm, Tuula (2020)
    This study investigated the mechanisms of the co-migration of phytic acid during beta-glucan isolation and its contribution to the retardation of starch hydrolysis in vitro. During the isolation, phytic acid precipitated together with beta-glucan when ethanol was added as the precipitation solvent. The precipitation of phytic acid was reduced by lowering the pH or the ethanol concentration. When 20% (NH4)(2)SO4 was used as the precipitation solvent, only minor phytic acid was found in isolated beta-glucan, because phytic acid did not precipitate by this solvent. In the in vitro starch hydrolysis test, the isolated oat beta-glucan (OBG) containing 3.9% co-migrated phytic acid showed better retardation effect than OBG containing 0.6% phytic acid. Therefore, we concluded that the co-migration of phytic acid was dependent on the chosen isolation procedure and conditions, and both intrinsic phytic acid and viscosity contributed to the retardation of starch hydrolysis.
  • Bublyk, Olena M.; Andreev, Igor O.; Kalendar, Ruslan; Spiridonova, Kateryna V.; Kunakh, Viktor A. (2013)
  • Mäkelä, Noora; Maina, Ndegwa H.; Vikgren, Päivi; Sontag-Strohm, Tuula (2017)
    Viscosity of cereal beta-glucan during digestion is considered to be a vital factor for its health effects. Thus, studies on solution properties and gelation are essential for understanding the mechanisms of the beta-glucan functionality. The aim of this study was to investigate the effect of the dissolution temperature on gelation of cereal beta-glucan at low concentrations that are relevant for food products. The rheological properties of oat and barley beta-glucans (OBG and BBG) using three dissolution temperatures (37 degrees C, 57 degrees C and 85 degrees C) at low concentration (1.5% and 1%, respectively) were studied for 7 days. Additionally, the beta-glucans were oxidised with 70 mM H2O2 and 1 mM FeSO4 x 7H(2)O as a catalyst, to evaluate the consequence of oxidative degradation on the gelation properties. The study showed that dissolution at 85 degrees C did not result in gelation. The optimal dissolution temperature for gelation of OBG was 37 degrees C and for gelation of BBG 57 degrees C. At these temperatures, also the oxidised OBG and BBG gelled, although the gel strength was somewhat lower than in the non-oxidised ones. Gelation was suggested to require partial dissolution of beta-glucan, which depended on the molar mass and aggregation state of the beta-glucan molecule. Therefore, the state of beta-glucan in solution and its thermal treatment history may affect its technological and physiological functionality. (C) 2017 Elsevier Ltd. All rights reserved.
  • Turzhanova, Ainur; Khapilina, Oxana; Tumenbayeva, A; Shevtsov, Vladislav; Raiser, Olesya; Kalendar, Ruslan (2020)
    The genus Alternaria is a widely distributed major plant pathogen that can act as a saprophyte in plant debris. Fungi of this genus frequently infect cereal crops and cause such diseases as black point and wheat leaf blight, which decrease the yield and quality of cereal products. A total of 25 Alternaria sp. isolates were collected from germ grains of various wheat cultivars from different geographic regions in Kazakhstan. We investigated the genetic relationships of the main Alternaria species related to black point disease of wheat in Kazakhstan, using the inter-primer binding site (iPBS) DNA profiling technique. We used 25 retrotransposon-based iPBS primers to identify the differences among and within Alternaria species populations, and analyzed the variation using clustering (UPGMA) and statistical approaches (AMOVA). Isolates of Alternaria species clustered into two main genetic groups, with species of A.alternata and A.tennuissima forming one cluster, and isolates of A. infectoria forming another. The genetic diversity found using retrotransposon profiles was strongly correlated with geographic data. Overall, the iPBS fingerprinting technique is highly informative and useful for the evaluation of genetic diversity and relationships of Alternaria species.
  • Ghonaim, Marwa; Kalendar, Ruslan; Barakat, Hoda; Elsherif, Nahla; Ashry, Naglaa; Schulman, Alan (2020)
    Maize is one of the world’s most important crops and a model for grass genome research. Long terminal repeat (LTR) retrotransposons comprise most of the maize genome; their ability to produce new copies makes them efficient high-throughput genetic markers. Inter-Retrotransposon-Amplified Polymorphisms (IRAPs) were used to study the genetic diversity of maize germplasm. Five LTR retrotransposons (Huck, Tekay, Opie, Ji, and Grande) were chosen, based on their large number of copies in the maize genome, whereas polymerase chain reaction primers were designed based on consensus LTR sequences. The LTR primers showed high quality and reproducible DNA fingerprints, with a total of 677 bands including 392 polymorphic bands showing 58% polymorphism between maize hybrid lines. These markers were used to identify genetic similarities among all lines of maize. Analysis of genetic similarity was carried out based on polymorphic amplicon profiles and genetic similarity phylogeny analysis. This diversity was expected to display ecogeographical patterns of variation and local adaptation. The clustering method showed that the varieties were grouped into three clusters differing in ecogeographical origin. Each of these clusters comprised divergent hybrids with convergent characters. The clusters reflected the differences among maize hybrids and were in accordance with their pedigree. The IRAP technique is an efficient high-throughput genetic marker-generating method.
  • Rosa-Sibakov, Natalia; Mäkelä, Noora; Aura, Anna-Marja; Sontag-Strohm, Tuula; Nordlund, Emilia (2020)
    The objective of this work was to evaluate the role of beta-glucan molecular weight (M-w) and the presence of other carbohydrates on the physiological functionality of oat branviaanin vitrodigestion study. A complete approach using three differentin vitrodigestion models (viscosity of the small intestine digest, reduction of bile acids and on-line measurement of gas evolution) was used to predict the physiological functionality of enzymatically modified oat bran concentrate (OBC). OBC was enzymatically treated with two beta-glucanase preparations at three different levels in order to specifically decrease beta-glucanM(w)(Pure: purified beta-glucanase) or beta-glucan and other cell wall polysaccharides (Mix: commercial food-grade cell wall degrading enzyme preparation). TheM(w)of beta-glucan in OBC was tailored to high (1000 kDa), medium (200-500 kDa) and low (
  • Kalendar, Ruslan; Raskina, Olga; Belyayev, Alexander; Schulman, Alan (2020)
    Retrotransposable elements are widely distributed and diverse in eukaryotes. Their copy number increases through reverse-transcription-mediated propagation, while they can be lost through recombinational processes, generating genomic rearrangements. We previously identified extensive, structurally uniform retrotransposon groups in which no member contains the gag, pol, or env internal domains. Because of the lack of protein-coding capacity, these groups are non-autonomous in replication, even if transcriptionally active. The Cassandra element belongs to the non-autonomous group called terminal-repeat retrotransposons in miniature (TRIM). It carries 5S RNA sequences with conserved RNA polymerase (pol) III promoters and terminators in its long terminal repeats (LTRs). Here, we identified multiple extended tandem arrays of Cassandra retrotransposons within different plant species, including ferns. At least 12 copies of repeated LTRs (as the tandem unit) and internal domain (as a spacer), giving a pattern that resembles the cellular 5S rRNA genes, were identified. Cytogenetic analysis revealed the specific chromosomal pattern of the Cassandra retrotransposon with prominent clustering at and around 5S rDNA loci. The secondary structure of the Cassandra retroelement RNA is predicted to form super-loops, in which the two LTRs are complementary to each other and can initiate local recombination, leading to the tandem arrays of Cassandra elements. The array structures are conserved for Cassandra retroelements of different species. We speculate that recombination events similar to those of 5S rRNA genes may explain the wide variation in Cassandra copy number. Likewise, the organization of 5S rRNA gene sequences is very variable in flowering plants; part of what is taken for 5S gene copy variation may be variation in Cassandra number. The role of the Cassandra 5S sequences remains to be established.
  • Mäkelä, Noora; Brinck, Outi; Sontag-Strohm, Tuula (2020)
    The physiological functionality of cereal beta-glucan (beta-glucan) has been mainly attributed to its ability to form viscous solutions in the gastrointestinal (GI) tract. The viscosity is dependent on the concentration, extractability and molecular weight of beta-glucan, and to enable maximal functionality, these factors should therefore be acknowledged and their role in the physiological functionality of cereal beta-glucan further studied. An in vitro GI simulation with separate oral, gastric and small intestine phases was used to model the state of beta-glucan from various oat products in the GI tract. A rather large variation (from 26% to 99%) was observed in the extractabilities between product categories, with the highest extractabilities observed in spoonable products. The viscosities also varied highly within categories. When the comparison was done at similar concentration levels, the highest viscosities were observed in the products produced through dry processes, and moisture content during processing was suggested to be essential to the extent of beta-glucan degradation. The viscosity in samples that were likely to exhibit enzymatic activity was shown to be rather low, and thus the physiological functionality of beta-glucan may be threatened if the product also contains grain ingredients other than kiln-dried oat. Clear differences were observed in the functionality of beta-glucan in the GI tract model depending on a product type, and these were explained by differences in ingredients and processes. However, further studies are needed to specify the influence of each factor and to clarify the factors determining the physiological functionality of beta-glucan in food products.