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1

Optimization of extraction processes of water-soluble polysaccharides under the electric fielda action

Malyushevskaya Antonina, Yushchishina Anna, Mitryasova Olena, Pohrebennyk Volodymyr, Salamon Ivan

Przegląd Elektrotechniczny

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2021

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R. 97, nr 12

73--76

EN

The process of water extraction of polysaccharides was experimentally investigated when pulsed, alternating and direct current passes through the suspension "hyssop grass - water".

PL

Eksperymentalnie zbadano proces ekstrakcji wody polisacharydów, gdy przez zawiesinę „trawa hyzopowa – woda” przepływa prąd pulsacyjny, zmienny i stały.

2

A Morphological Characterization of High Yield Chitin from Periwinkle Shells

Odili Cletus Chiosa, Philips Gbenebor Oluwashina, Adekola Haffner Henry, Oluropo Adeosun Samson

Journal of Casting & Materials Engineering

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2021

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Vol. 5, no. 4

61--65

EN

Research on obtaining chitin from periwinkle shell is scarce due to the very low yield of chitin from this kind of shell. This study reports a method of processing periwinkle shells to obtain high yield, bio-medically suitable chitin. The experiment was designed using IM and 2M concentrations of HCl for demineralization and a 1M NaOH concentration for deproteinization. FTIR, SEM, XRD and DTA analytical tools were used to characterize the extracted chitin. The FTIR spectral, XRD patterns and SEM analysis, revealed the complete removal of calcium carbonate by the acid concentrations used. The particle-like form of periwinkle shell was transformed to sheet-like fiber and globular-like fiber of α-chitin by increasing the concentration of HCl from1M to 2M respectively. The crystal size increased from 11.2Å (1M HCl) to 13.4Å (2M HCl). The yield of chitin from periwinkle shell also increased from 52% to 71% using 1M and 2M HCl respectively. Thus, acid concentrations can be used to alter the structure of chitin with different mechanical properties.

3

Rheological properties of gelatin gels with sodium alginate

Derkatch S. R., Voronko N. G., Izmailova V. N.

International Journal of Applied Mechanics and Engineering

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2001

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Vol. 6, no 3

659-673

EN

The effect of anionic polysaccharide sodium alginate on the rheological properties of gelatin gels at pH values more than isolectric point of gelatin macromolecules has been investigated. The results of rheological measurements within the non-linear viscoelasticity range have been studied using Hershel-Bulkley model and Casson model. The analysis of the rheological curves allows characterizing the gelatin gels of low concentration of sodium alginate as viscoelastic-plastic material. Sodium alginate additions give non-monotonous change of the rheological parameters with clearly expressed extreme points for the multicomponent gels in comparison with the gelatin gels. In the presence of polysaccharide the rate of three-dimensional structure formation increases. A range of sodium alginate/gelatin ratios with extreme values of the rheological characteristics has been discovered.

4

Rheology of ceramic suspensions in aqueous polysaccharide matrices

Lapasin R., Zupancic A.

Applied Mechanics and Engineering

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1999

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Vol. 4, no spec.

357-362

EN

Several polysaccharides exhibit weak gel properties when dissolved in aqueous phases and, hence, they can be profitably used to prepare aqueous matrices suitable to host disperse phases and to improve the stability and workability of the dispersions. Such an application is particularly interesting in the ceramic field, where high concentration levels of the disperse phase must be reached. In the present paper the rheological properties of concentrated dispersions of ceramic powders (alumina and calcium carbonate) in aqueous polysaccharide matrices (welan and rhamsan) are examined under flow conditions as well as in the linear viscoelastic regime. The comparison with the corresponding properties of aqueous suspensions and polysaccharide matrices highlights the beneficial effects of the polymer addition. The results obtained can be considered paradigmatic of the advantages deriving from the usage of such polymers for the rheological and stability properties of many other disperse systems.