scholarly journals Oligochitosan Hydrochloride: Preparation and Characterization

INEOS OPEN ◽  
2021 ◽  
Vol 4 ◽  
Author(s):  
V. E. Tikhonov ◽  
◽  
B. B. Berezin ◽  
I. V. Blagodatskikh ◽  
E. A. Bezrodnykh ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Molecular Weight ◽  
Hydrochloric Acid ◽  
Physicochemical Properties ◽  
High Molecular Weight ◽  
Synthetic Approach ◽  
European Pharmacopoeia ◽  
High Molecular Weight Chitosan ◽  
Analytical Protocols

The methods commonly used for depolymerization of chitosan and preparation of oligochitosan are discussed. A synthetic approach to oligochitosan hydrochloride with a molecular weight below 16 kDa based on the treatment of parent industrial high molecular weight chitosan with a mixture of hydrochloric acid and hydrogen peroxide is described. A series of analytical protocols are used to determine the physicochemical properties and quality of resulting oligochitosan hydrochloride according to the European Pharmacopoeia 4.0.

scholarly journals Catalytic Degradation of Chitosan by Supported Heteropoly Acids in Heterogeneous Systems

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1078
Author(s):  
Hang Zhang ◽  
Zhipeng Ma ◽  
Yunpeng Min ◽  
Huiru Wang ◽  
Ru Zhang ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Molecular Weight ◽  
Catalytic Activity ◽  
Activated Carbon ◽  
Reaction Time ◽  
High Molecular Weight ◽  
Reaction Temperature ◽  
Water Soluble ◽  
High Catalytic Activity ◽  
High Molecular Weight Chitosan

Several kinds of composite materials with phosphotungstic acid (PTA) as the catalyst were prepared with activated carbon as support, and their structures were characterized. According to the Box–Behnken central combination principle, the mathematical model of the heterogeneous system is established. Based on the single-factor experiments, the reaction temperature, the reaction time, the amount of hydrogen peroxide and the loading capacity of PTA were selected as the influencing factors to study the catalyzed oxidation of hydrogen peroxide and degradation of high molecular weight chitosan. The results of IR showed that the catalyst had a Keggin structure. The results of the mercury intrusion test showed that the pore structure of the supported PTA catalyst did not change significantly, and with the increase of PTA loading, the porosity and pore volume decreased regularly, which indicated that PTA molecules had been absorbed and filled into the pore of activated carbon. The results of Response Surface Design (RSD) showed that the optimum reaction conditions of supported PTA catalysts for oxidative degradation of high molecular weight chitosan by hydrogen peroxide were as follows: reaction temperature was 70 ℃, reaction time was 3.0 h, the ratio of hydrogen peroxide to chitosan was 2.4 and the catalyst loading was 30%. Under these conditions, the yield and molecular weight of water-soluble chitosan were 62.8% and 1290 Da, respectively. The supported PTA catalyst maintained high catalytic activity after three reuses, which indicated that the supported PTA catalyst had excellent catalytic activity and stable performance compared with the PTA catalyst.

scholarly journals Changes in the Respiration, Growth, and Vitamin C Content of Soybean Sprouts in Response to Chitosan of Different Molecular Weights

HortScience ◽  
2005 ◽  
Vol 40 (5) ◽  
pp. 1333-1335 ◽  
Author(s):  
Young-Sang Lee ◽  
Yong-Ho Kim ◽  
Sung-Bae Kim
Keyword(s):  
Molecular Weight ◽  
Vitamin C ◽  
High Molecular Weight ◽  
Soybean Seeds ◽  
Hypocotyl Length ◽  
Molecular Weights ◽  
Soybean Sprouts ◽  
High Molecular Weight Chitosan ◽  
Chlorophyll Formation

To study the effects of chitosan on the productivity and nutritional quality of soybean (Glycine max L.) sprouts, soybean seeds were soaked in solutions containing 1,000 ppm chitosan of low (<10 kDa), medium (50 to 100 kDa), or high (>1,000 kDa) molecular weight, and the respiration, growth, and vitamin C content of the sprouts were subsequently evaluated. Sprouts treated with high molecular weight chitosan exhibited a significant increase in respiration, 5%, within 1 day of treatment. Chitosan effectively increased the growth of the sprouts: sprouts treated with high molecular weight chitosan showed increases of 3%, 1%, 3%, 1%, and 12% in the total length, hypocotyl length, root length, hypocotyl thickness, and fresh weight, respectively, as compared to a control. The growth-improving effects of chitosan were proportional to the molecular weight of the molecule used in the treatment. Chitosan treatment did not result in any significant reduction in vitamin C content or postharvest chlorophyll formation, traits that determine the nutritional and marketing values of soybean sprouts. All these results suggest that soaking soybean seeds in a solution of chitosan, especially of high molecular weight, may effectively enhance the productivity of soybean sprouts without adverse effects on the nutritional and postharvest characteristics.

scholarly journals The Effect of Chitosan Type on Biological and Physicochemical Properties of Films with Propolis Extract

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3888
Author(s):  
Karolina Stanicka ◽  
Renata Dobrucka ◽  
Magdalena Woźniak ◽  
Anna Sip ◽  
Jerzy Majka ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Physicochemical Properties ◽  
High Molecular Weight ◽  
Food Packaging ◽  
Transmission Rate ◽  
Antimicrobial Properties ◽  
Propolis Extract ◽  
Oxygen Transmission Rate ◽  
Extract Concentration ◽  
High Molecular Weight Chitosan

The aim of the research was to determine the influence of chitosan type and propolis extract concentration on biological and physicochemical properties of chitosan-propolis films in terms of their applicability in food packaging. The films were prepared using three types of chitosan: from crab shells, medium and high molecular weight and propolis concentration in the range of 0.75–5.0%. The prepared polysaccharide films were tested for antimicrobial properties, oxygen transmission rate (OTR) and water vapor transmission rate (WVTR). Moreover, sorption tests and structural analysis were carried out. Microbiological tests indicated the best antimicrobial activity for the film consisting of high molecular weight chitosan and 5.0% propolis extract. Both the type of chitosan and propolis concentration affected transmission parameters—OTR and WVTR. The best barrier properties were recorded for the film composed of high molecular weight chitosan and 5.0% propolis extract. The results of sorption experiments showed a slight influence of chitosan type and a significant effect of propolis extract concentration on equilibrium moisture content of tested films. Moreover, propolis extract concentration affected monolayer water capacity (Mm) estimated using the Guggenheim, Anderson and de Boer (GAB) sorption model. The obtained results indicate that chitosan films with an addition of propolis extract are promising materials for food packaging applications, including food containing probiotic microorganisms.

scholarly journals Physicochemical and Antifungal Properties of Clotrimazole in Combination with High-Molecular Weight Chitosan as a Multifunctional Excipient

Marine Drugs ◽  
2020 ◽  
Vol 18 (12) ◽  
pp. 591
Author(s):  
Bożena Grimling ◽  
Bożena Karolewicz ◽  
Urszula Nawrot ◽  
Katarzyna Włodarczyk ◽  
Agata Górniak
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Weight Ratio ◽  
Scanning Calorimetry ◽  
Minimal Inhibitory Concentrations ◽  
Dissolution Tests ◽  
Effective Combination ◽  
The Impact ◽  
High Molecular Weight Chitosan

Chitosans represent a group of multifunctional drug excipients. Here, we aimed to estimate the impact of high-molecular weight chitosan on the physicochemical properties of clotrimazole–chitosan solid mixtures (CL–CH), prepared by grinding and kneading methods. We characterised these formulas by infrared spectroscopy, differential scanning calorimetry, and powder X-ray diffractometry, and performed in vitro clotrimazole dissolution tests. Additionally, we examined the antifungal activity of clotrimazole–chitosan mixtures against clinical Candida isolates under neutral and acid conditions. The synergistic effect of clotrimazole and chitosan S combinations was observed in tests carried out at pH 4 on Candida glabrata strains. The inhibition of C. glabrata growth reached at least 90%, regardless of the drug/excipient weight ratio, and even at half of the minimal inhibitory concentrations of clotrimazole. Our results demonstrate that clotrimazole and high-molecular weight chitosan could be an effective combination in a topical antifungal formulation, as chitosan acts synergistically with clotrimazole against non-albicans candida strains.

Modification of a novel x-type high-molecular-weight glutenin subunit gene from Aegilops markgrafii to improve dough strength of wheat flour

2018 ◽  
Vol 69 (9) ◽  
pp. 873
Author(s):  
Xin Ma ◽  
Xuye Du ◽  
Cunyao Bo ◽  
Hongwei Wang ◽  
Anfei Li ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Wheat Flour ◽  
Cysteine Residue ◽  
Site Directed Mutagenesis ◽  
Cysteine Residues ◽  
Dough Strength ◽  
Typical Structure ◽  
Dough Quality

High-molecular-weight glutenin subunits (HMW-GS) in bread wheat are major determinants of dough viscoelastic properties and the end-use quality of wheat flour. Cysteine residues, which form intermolecular disulphide bonds in HMW-GS, could improve the strength of gluten. To our knowledge, the number and position of cysteine residues in HMW-GS are conserved between wheat (Triticum aestivum) and Aegilops markgrafii. In the present study, we modified a gene (1Cx1.1) from Ae. markgrafii for an HMW-GS that possessed the typical structure and conserved number of cysteines. Site-directed mutagenesis was carried out in 1Cx1.1 to investigate how the position of cysteine residues in HMW-GS affects the mixing properties of dough. Six HMW-GS containing an extra cysteine residue were expressed in Escherichia coli, and the proteins were purified at sufficient scale for incorporation into flour to test dough quality. There were large differences in dough property among samples containing different modified subunits. Cysteine substituting in the N-terminal or repetitive-domain of HMW-GS could significantly improve dough quality. The results showed that the strategy was useful for providing genetic resources for gene engineering, and hence could be valuable for improving the processing quality of wheat.

scholarly journals The Influence of the Use of Polymer Lining within the Roller Press Gravity Feeder on Briquette Quality

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2489
Author(s):  
Michał Bembenek
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Material Flow ◽  
Laboratory Tests ◽  
Polymer Materials ◽  
Roller Press ◽  
Fine Grained ◽  
The Impact ◽  
Ultra High Molecular Weight

When considering the operation of roller presses for the consolidation of fine-grained materials, the main problems are disturbances in the proper flow of the material and its bridging in gravity feeders. This is especially true for small and medium capacity presses, where the hoppers for dosing the material are narrow. This article presents innovative laboratory tests of the impact of using a polymer plate lining in the gravity feeder of a roller press. Polymer materials Polyacetal C (POM C) and Ultra-High-Molecular-Weight Polyethylene (UHMW-PE) were used for the tests. The influence of the use of plates on the material flow and quality of briquettes was investigated in comparison with the case where such plates were not used. The research showed an improvement in the flow of fine-grained materials in the feeder and an increase of the briquette strength indexes, as compared to those cases when polymer linings were not used in the feeder.

Sign in / Sign up

Export Citation Format

Share Document