A copolymer analysis approach to estimate the neutral sugar distribution of sugar beet pectin using size exclusion chromatography

Partially degraded sugar beet (Beta vulgaris) pectins were characterised in terms of galacturonic acid, neutral sugar and ferulic acids contents. It was shown that the total neutral sugar content is correlated with the ferulic acid content. One pectin (C) was further characterised by size exclusion chromatography coupled to refractive index and UV detectors (SEC-RI-UV). This gave the opportunity to estimate how the ferulic acid and neutral sugar contents changed with hydrodynamic radius. Pectin C was found to be heterogeneous in composition with neutral sugar-rich fractions of both high and low hydrodynamic radii. A neutral sugar-poor fraction was found at intermediate hydrodynamic radii

Les protéines de pomme de terre : composition, isolement et propriétés fonctionnelles

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Enthalpic studies of xyloglucan-cellulose interactions

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Etudes par RMN à bas champ des propriétés physico-chimiques du mucilage interne de graines provenant de 19 acessions d'Arabidopsis

International audienceMucilage is a hydrogel formed from polysaccharides released from imbibed Arabidopsis seeds. These polysaccharides are accumulated in the epidermal cells of the seed coat during seed development. The role of this mucilage remains to be determined, but its absence is not detrimental in laboratory conditions, making it an excellent model for the study of polysaccharide properties. We have previously shown that Arabidopsis mucilage is formed of a mixture of polysaccharides in two structurally distinct layers, both of which are mainly composed of the pectin rhamnogalacturonan I. In a previous project, biochemical data were obtained from 301 Arabidopsis natural variants concerning the natural variation in outer mucilage physicochemical properties (Tran et al., unpublished). Low-field NMR spectroscopy was developed for the characterization of water uptake into seeds during imbibition, based on T2 relaxation times assigned to water mobility in the different mucilage layers (Saez-Aguayo et al., 2014). The work presented here will focus on low-field NMR applied to the characterization of the physicochemical properties of the inner layer for 19 selected accessions. Eighteen of these genotypes have particularly divergent characteristics compared to the Col-0 reference accession. For each seed, T2 relaxation times were measured and correlations identified with regard to the sugar composition of the inner and outer layers, and the width of the inner layer

Predicting the influence of climate induced temperature changes on the production of polysaccharides in Arabidopsis seed mucilage

International audienceIn recent years, the climate trend in temperate zones such as Europe and North America has been towards episodes of severe hot weather which are projected to occur more frequently and/or severely over coming decades (IPCC fifth assessment report, 2014). This is predicted to have major effects on ecosystems and the biodiversity of wild species, such as Arabidopsis. Polysaccharides play a key role in plant growth and resistance to stress and how their production will be affected by climate change remains an open question. Mucilage is a hydrogel of polysaccharides formed around imbibed seeds of certain species and is an amenable model system for studying polysaccharide production. We have previously found that natural accessions of Arabidopsis show variation in mucilage production that may be locally adapted to particular climates. To determine how climate change can impact polysaccharide synthesis, we have examined the effect of temperature on the production of seed mucilage polymers. Polysaccharide composition and properties in natural mucilage variants exhibiting divergent traits under standard growth conditions have been compared after seed production at different temperatures. How these are related to the modulation of genes encoding key enzymes in mucilage polysaccharide synthesis will also be presented

Physicochemical changes in dietary fiber of green beans after repeated microwave treatments

The influence of microwave cooking/reheating on dietary fiber in green beans was investigated. The beans were analyzed after blanching and following repeated microwave treatment. Content and composition of dietary fiber as well as molecular weight distribution and viscosity of indigestible water-soluble polysaccharides (WSP) (Mw >1000) were determined. Total fiber content decreased only after the most severe microwave treatment, primarily due to losses of soluble dietary fiber (pectic polymers). Molecular weight and viscosity decreased considerably after the first microwave treatment. Repeated microwave treatments reduced the molecular weight further, but not the viscosity