Production of Oligosaccharides as Promising New Food Additive Generation

Nedavna istraživanja ugljikohidratnih sastojaka hrane potvrdila su djelotvornost uporabe oligosaharida kao prebiotika ili biokonzervansa. Prebiotički oligosaharidi imaju različito podrijetlo i strukturu, a biokonzervansi su uglavnom oligohitozani ili hitozani male molekularne mase. Nova biotehnološka proizvodnja bitno je pridonijela razvoju tih funkcionalnih sastojaka hrane, a njihovu primjenu ograničava specifična glikozidna struktura. Ovaj revijalni prikaz donosi niz spoznaja te popis procesa tvorbe bioaktivnih oligosaharida.Recent research in the area of carbohydrate food ingredients has shown the efficiency of oligosaccharides when they are used as prebiotics or biopreservatives. Considering the former, they have various origins and structures, whereas the latter are described mostly as oligochitosans or as low molecular mass chitosans. If new manufacturing biotechnologies have significantly increased the development of these functional food ingredients, the main drawback limiting their applications is the difficulty to engender specific glycosidic structures. The present review focuses on the knowledge in the area of food bioactive oligosaccharides and catalogues the processes employed to generate them

Antidiabetic potential of mucilage fraction extracted from Astragalus gyzensis seeds

The objective of the current work is to extract a new mucilage fraction from Astragalus gyzensis Bunge. seeds, which are collected from the El-Oued province (septentrional Algerian Sahara) and evaluated for their antidiabetic potential. The mucilage fraction is obtained using hot water extraction followed by alcoholic precipitation of polysaccharides by cold ethanol (96%). The primary investigation was performed by describing the main structural features of the extract through colorimetric assays, Fourier-transform infrared spectroscopy and thin-layer chromatography analysis using two systems. Biological activity was also monitored by antidiabetic activity by testing the inhibition of α-amylase and α-glucosidase enzymes in vitro. The extraction yield was 20.69%. The chemical composition mainly consisted of 78.60±0.29% carbohydrates, among them 63.92±0.67% neutral sugar, 15.78±0.76% uronic acid, 8.08±0.04% proteins and 2.57±0.05% phenolic compounds. The results obtained by thin-layer chromatography analysis showed the dominance of mannose and galactose. Fourier-transform infrared spectrum showed characteristic bands expected galactomannans. The investigations highlighted the antihyperglycemic effect in a dose-dependent manner by the inhibition of the α-amylase enzyme (IC50=0.8±0.005 mg/mL). These factors make it suitable for the industrial application of dietary supplement fiber made for diabetic individuals. DOI: http://dx.doi.org/10.5281/zenodo.761853

Front Microbiol

Brettanomyces bruxellensis is the main spoilage microbial agent in red wines. The use of fungal chitosan has been authorized since 2009 as a curative treatment to eliminate this yeast in conventional wines and in 2018 in organic wines. As this species is known to exhibit great genetic and phenotypic diversity, we examined whether all the strains responded the same way to chitosan treatment. A collection of 53 strains of was used. In the conditions of the reference test, all were at least temporarily affected by the addition of chitosan to wine, with significant decrease of cultivable population. Some (41%) were very sensitive and no cultivable yeast was detected in wine or lees after 3 days of treatment, while others (13%) were tolerant and, after a slight drop in cultivability, resumed growth between 3 and 10 days and remained able to produce spoilage compounds. There were also many strains with intermediate behavior. The strain behavior was only partially linked to the strain genetic group. This behavior was little modulated by the physiological state of the strain or the dose of chitosan used (within the limits of the authorized doses). On the other hand, for a given strain, the sensitivity to chitosan treatment was modulated by the chitosan used and by the properties of the wine in which the treatment was carried out.Recherches sur l’origine et les effets secondaires des propriétés stabilisantes du chitosane fongique dans le vi

Etude de l'observabilité de systèmes de Sturm-Liouville : application aux réacteurs biochimiques à paramètres répartis/

Du fait du manque de capteurs fiables et bon marché, la problématique de la reconstruction d'état est cruciale pour les bioprocédés, particulièrement pour les (bio)réacteurs à paramètres répartis. C'est pourquoi il est essentiel d'étudier leurs propriétés d'observabilité, qui peuvent notamment dépendre des dimensions spatiales des capteurs. Dans cette thèse, on étudie tout d'abord l'observabilité d'une classe de réacteurs tubulaires à lit fixe mettant en oeuvre une seule réaction biochimique, où un substrat est dégradé suivant une cinétique non linéaire. Plus précisément, l'analyse porte sur un modèle linéarisé, consistant notamment en une Équation aux Dérivées Partielles (EDP) parabolique linéaire comportant un coefficient non uniforme (c.-à-d. dépendant de la variable spatiale). Ce modèle entre dans le cadre d'une classe particulière de systèmes : les systèmes de Sturm-Liouville. Il s'en déduit que tout nombre fini de modes dominants du système est observable par un capteur (de concentration en substrat) situé en sortie et de largeur suffisamment petite. En outre, considérant un minorant et un majorant du coefficient non uniforme, on détermine une expression numérique, fonction du nombre de modes à observer, qui minore cette largeur. La pertinence de ce résultat est confirmée par un exemple numérique : un biofiltre de dénitrification. Cette étude est étendue à un procédé-pilote de digestion anaérobie de l'INRA-Narbonne. On montre l'existence d'un état d'équilibre, autour duquel le comportement du système est modélisé par deux EDP linéaires, dont une à coefficient non uniforme. La démarche précédente est généralisée et on calcule des expressions des largeurs de deux capteurs en fonction du nombre de modes dont on veut s'assurer qu'ils sont observables. Ce résultat s'applique notamment à la conception d'un estimateur d'��tat.(FSA 3)--UCL, 200

Current Opinion on Chitosan and its Derivatives: Biological Impact in Antimicrobial Applications From Nature to Chitosan and It Derivatives: How it is Working?

International audienceCurrently, lots of medical applications are investigated by using natural biopolymers such as polysaccharides. In this field chitosan is probablyone of the most employed polysaccharides possessing very high pharmaceutical potential due to its chemo-physical and biological properties.The recent progresses in chemistry and biotechnologies apply to chitosan such as chemical and enzymatic modification allowed us to synthesizelot of biodegradable and biocompatible chitosan derivatives with huge impact in antimicrobial area. This present opinion describes the mostwidely described strategies for generate antimicrobial chitosan and derivatives by chemical/enzymatic structural macromolecular modification

Stratégie d'obtention d'oligosaccharides anioniques par dégradation enzymatique de glucuronanes

AMIENS-BU Sciences (800212103) / SudocSudocFranceF

Conditions for interpolation of stable polynomials

Abstract-This contribution addresses the problem of the interpolation of a set of positive numbers by stable real polynomials. It is shown that the interpolant preserves local positivity, monotonicity, and convexity in order to satisfy stability requirement of the interpolating polynomial. Then this issue is formulated as a nonlinear system carrying on the existence of negative real roots and positive real parameters. By considering an extension of the Farkas's Lemma and the method of FourierMotzkin elimination, conditions are explicitly produced for the existence of an Hurwitz polynomial that passes through all the pairs of values to interpolate

Observability analysis of nonlinear tubular (bio)reactor models: A case study

This paper deals with the observability analysis of nonlinear tubular bioreactor models. Due to the lack of tools for the observability analysis of nonlinear infinite-dimensional systems, the analysis is performed on a linearized version of the model around some steady-state profile, in which coefficients can be functions of the spatial variable. The study starts from an example of tubular bioreactor that will serve as a case study in the present paper. It is shown that such linear models with coefficients dependent on the spatial variable are Sturm-Liouville systems and that the associated linear infinite-dimensional system dynamics are described by a Riesz-spectral operator that generates a C-0 (strongly continuous)-semigroup. The observability analysis based on infinite-dimensional system theory shows that any finite number of dominant modes of the system can be made observable by an approximate point measurement. (C) 2003 Elsevier Ltd. All rights reserved