Degree Of Deacetylation Value Research Articles

Solid-state mechanochemical synthesis of chitosan from mud crab (Scylla serrata) chitin

This study presents a method for solvent-free mechanochemical synthesis of chitosan from chitin, sourced from the shells of mud crabs (Scylla serrata). The procedure involves a sequence of demineralization and deproteinization to extract chitin from the crab shells, followed by mechanochemical deacetylation. The chitin was deacetylated by grinding it as a solid blend with sodium hydroxide (NaOH) using a stainless steel mortar and pestle. After grinding, chitosan is isolated from the blend by repetitive washing and centrifugation. The chitosan product is then characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction analysis. These characterization techniques confirm the successful deacetylation of chitin to form chitosan. A high degree of deacetylation (DD) is achieved when the weight ratio of NaOH to chitin is 1:1 or higher, implying that the DD value can be enhanced by increasing this weight ratio. The mechanochemical reaction mechanism involves the hydroxyl groups on the NaOH particles reacting with the acetamide groups of the chitin strands, yielding solid chitosan and sodium acetate. This mechanochemical deacetylation approach is more practical than the conventional heterogeneous deacetylation in strong basic solutions, since it could suppress depolymerization of the resulting chitosan and requires significantly less base. This makes it a promising method for large-scale industrial applications.

Characterisation and Analysis of Chitosan Extract from Artemia franciscana Using SEM, FT-IR and XRD Studies

Introduction: Artemia franciscana is one of the best animal models which is used in various fields. After the hatching of Artemia the shell wastes are used for Chitosan extraction. The extraction process consumes less time when compare with other shells because of its shell size.
 Materials and Methods: The Chitosan extract was prepared using Artemia shells. The Physico-chemical properties were analysed and characterization of Chitosan extract was done using SEM, XRD and FT-IR studies.The physicochemical properties of the extracted chitosan indicate that it has optimum values desirable for wound healing applications. Chitosan has high water and fat binding capacity that can help to maintain a moist environment on the wound surface and control inflammation, respectively. The degree of deacetylation (DD) of chitosan is critical in determining its biological activities. The DD value obtained in this study was 84.77%, indicating that the chitosan sample had a high degree of deacetylation. Outcomes: The morphology of the chitosan membrane is an important factor that influences its properties and potential applications, including wound healing.
 Results: The SEM images obtained in this study revealed that pure chitosan exhibited a nonporous, smooth membranous phase with dome-shaped orifices, microfibrils, and crystallites. The XRD analysis results suggest that the chitosan used in this study is highly crystalline, with both crystalline and amorphous regions enhancing its bioactivity and biocompatibility, making it a promising material for wide range of application in medicine. The crystalline and amorphous structure of Chitosan is analysed by the XRD, SEM and FT-IR reveals its wide range of applications in medicine.

A facile approach for the determination of degree of deacetylation of chitosan using acid-base titration

Several spectroscopic techniques such as nuclear magnetic resonance (NMR), UV-visible, Fourier transform infrared (FT-IR), etc. have been already used for the determination of degree of deacetylation (DD) of chitosan. These techniques involve the interpretation of spectral data apart from sample preparation for obtaining DD of chitosan. In addition, inaccurate interpretation of data sometimes misleads researchers to get an exact value of DD of chitosan. Among them, NMR is an excellent technique for the estimation of DD of chitosan but expensive and not found easily in every research laboratory. On the other hand, titrimetric methods have been employed by many researchers for determining the DD of chitosan but these existing methods involve many complex calculations, which do not always give accurate results. Moreover, few of the acid-base titration methods are little complicated for execution. Therefore, in this present study, we adopted a very handy and simple acid-base titration method with a new approach and proposed a new equation facilitating the ease of calculation that is not reported elsewhere for the determination of DD value by observing the net volume of NaOH consumed for the complete neutralization of protonated amino groups (-NH3+) of chitosan describing the novelty of the work. All the DD values (77.04 ± 1.36; 81.71 ± 1.73; 91.68 ± 1.42 for CS1, CS2, and CS3 respectively) obtained for various chitosan samples were in good agreement with the reported DD values (>75%, >80%, and >85% for CS1, CS2, and CS3 respectively) mentioned in the specifications of chitosan samples supplied by the manufacturer. Finally, the experimental DD values were further validated with the DD values (77.39%, 81.64%, and 90.5% for CS1, CS2, and CS3 respectively) obtained from the interpretation of 13C-NMR spectral data and all the experimental DD values were consistent with the DD values as calculated based on NMR spectra.

Chitosan Synthesis and Optimization of Root Endophytic Fungi

The cell wall component of root endophytic fungi is a main source of chitosan synthesis. This research aimed to optimize chitosan synthesis from three different isolated species of root endophytic fungi in Pulau Dua Nature Reserve, Banten Indonesia. Three species of root endophytic fungi, namely, Aspergillus niger, Aureobasidium sp., Basipetospora sp., were cultured to produce chitosan. To optimize the production of fungal chitosan, cultures were treated with different conditions such as growth medium (Oat Meal broth, Potato Dextrose Broth, CMMY Broth), pH value (4, 5, 6, 7), and temperature (25, 30, 35, 40°C). Chitosan was extracted from dried mycelium after treated on NaOH 10% at 121°C for 2 min. The degree of deacetylation (DD) of chitosan was then examined and compared with the control (shrimp chitosan). The optimum fungal chitosan condition was higher in CMMY medium, pH 5, and 30°C. The DD value of three root endophytic fungi species, Aspergillus niger, Aureobasidium sp., Basipetospora sp. were 88.5, 83.3, 80.8, respectively, which was lower than DD value resulted from control. This study indicates that Aspergillus niger was a potential endophytic fungi for chitosan synthesis.

Optimization conversion of chitosan from Ganoderma lucidum spore powder using ultrasound‐assisted deacetylation: Influence of processing parameters

Chitosan is an extremely valuable polysaccharide and usually obtained from crustacean byproduct. In this work, a new non‐animal source chitosan is obtained from fungal precursors (Ganoderma lucidum spore powders, GLSP) using ultrasound‐assisted deacetylation (USAD), and the effects of processing parameters (irradiation time, solid‐to‐liquid ratio, NaOH concentration, and irradiation power) on the DD (degree of deacetylation) of chitosan were investigated. The highest DD value was obtained at irradiation parameters of 20 min, 10% (g:ml) NaOH, 1:25 (g:ml), and 80 W. In addition, the difference in surface morphology, chemical groups, thermal stability, and crystallinity of the resulting chitosan with the treatment of various irradiation times was examined using the SEM, FTIR, TG, and XRD. The results show a new promising herbal source of edible chitosan and the potential material for biomedical applications. PRACTICAL APPLICATIONS: The chitosan obtained from Ganoderma lucidum spore powders (GLSP) possessed many priorities over the chitosan from shells of crustaceans, which involves a multi‐faceted procedure with several economical and consumer related aspects. In the current work, chitosan is obtained from an herbal source GLSP using ultrasound treatment and the effect of processing parameters on chitosan was investigated. The findings show the development of chitosan from an herbal source with potential in functional food applications.

Rapid determination of degree of deacetylation of chitosan by a headspace analysis based Titrimetric technique

This paper reports on a novel method for rapid determination of the degree of deacetylation (DD) of chitosan samples by headspace gas chromatography (HS-GC). In this method, overdose of an acid is added to protonate the free amino groups in chitosan, which further reacts with bicarbonate (as an alkali titrant) in a close vial. Based on measuring the HS-GC signal for CO2vs. the volume of HCO3− added by a stepwise titration, two transition points can be obtained. The DD value is calculated by net volume of HCO3− consumed, i.e., by the RNH3+ groups in chitosan. The results showed that the present method has a good measurement precision (RSD < 0.82%) and accuracy (relative differences < 6.46% when compared with the results measured by a reference method). Since the HS-GC can perform an automated sample reaction equilibration and measurement, it could be much more efficient than the existing methods in the batch sample analysis.

Application of gamma radiation and physicochemical treatment to improve the bioactive properties of chitosan extracted from shrimp shell

Abstract The aim of this study is to exploit a suitable chitosan extraction method from the chitin of indigenous shrimp shells by employing different physicochemical treatments and to improve different bioactive properties of this extracted chitosan (CS) by applying gamma radiation. Chitin was prepared from shrimp shell by pretreatment (deproteination, demineralization and oxidation). Chitosan was extracted from chitin by eight different methods varying different physicochemical parameters (reagent concentration, temperature and time) and assessed with respect to the degree of deacetylation, requirement of time and reagents. The method where chitin was repeatedly treated with 121°C for 30 min with 20 M NaOH, produced the highest degree of deacetylation (DD) value (92%) as measured by potentiometric titration, with the least consumption of time and chemicals, and thus, selected as the best suitable extraction method. For further quality improvement, chitosan with highest DD value was irradiated with different doses (i.e., 5, 10, 15, 20 and 50 kGy) of gamma radiation from cobalt-60 gamma irradiator. As the radiation dose was increased, the molecular weight of the wet irradiated chitosan, as measured by the viscosimetric method, decreased from 1.16 × 105 to 1.786 × 103, 1.518 × 103, 1.134 × 103, 1.046 × 103 and 8.23 × 102 dalton, respectively. The radiation treatment of chitosan samples increased the antimicrobial activity significantly in concentration dependent manner on both gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria, as determined by the well-diffusion method. Four to five percent wet chitosan treated with a radiation dose range of 5.0–10.0 kGy rendered the highest antimicrobial activity with least energy and time consumption. Solubility, water binding capacity (WBC) and fat binding capacity (FBC) also improved due to irradiation of chitosan.

Microwave-Assisted Hydrolysis of Chitosan from Shrimp Shell Waste for Glucosammine Hydrochlorid Production

Chitin is the most widespread renewable natural sources following cellulose as the main source of chitosan. Chitin is isolated from crustacean waste and shrimp shells. Chitosan is derived from chitin throuhgt demineralisation, deproteination, decolorisation and deacetylation process using chemicals such as sodium hydroxide, hydrogen chloride and acetone. Glucosamine hydrochloride (GlcN-Cl) can be produced by hydrolysis of chitosan by using hydrogen chloride. During deacetylation and hydrolysis the solution is heated by hotplate or furnace. In this paper we use microwave instead of hotplate for production chitosan and GlcN-Cl. The research investigates effect of microwaves to amount of rendemen and their property. The chitosan was characterized its moisture content, solubility, and degree of deacetylation (DDA). Whereas the glucosammine hydrochloride characterized its functional groups using FTIR and crystallization by using X-Ray Difraction (XRD). The experimental results show that the use of microwave energy on deacetilation of chitosan and hydrolisis processes can decrease time consuming and reactant concentration during production. the DDA value obtained was very high from 70 to 85%. The results also show that microwaves meet chitosan and GlcN-Cl standards.

Dependence of corneal keratocyte adhesion, spreading, and integrin β1 expression on deacetylated chitosan coating

This study reports, for the first time, the regulation of corneal keratocyte adhesion, spreading, morphology, and integrin gene expression on chitosan coating due to the effects of deacetylation. The degree of deacetylation (DD) in chitosan materials was confirmed by elemental analysis, gel permeation chromatography, and Fourier transform infrared spectroscopy. In this study, chitosan samples with the same molecular weight level but varying DD (74.1±0.5%, 84.4±0.7%, and 94.2±0.5%) were obtained by heat-alkaline treatment under a nitrogen atmosphere. For higher DD groups, the biopolymer carried abundant amino groups since the deacetylation process removed larger amount of acetyl groups from the chitosan molecules. Results showed that the mechanical stability and crystallinity of the chitosan coatings significantly increased with increasing DD value. Fibronectin adsorption, keratocyte adhesion, and cell spreading exhibited a positive correlation with DD due to the chemical functionality of polysaccharides (bearing acetyl and amino groups) and increase of substrate stiffness and crystallinity. In particular, when adhered to chitosan coatings with a DD value of 74.1%, the keratocytes appeared to be fibroblastic, elongated, and spindle shape, indicating a loss of their characteristic dendritic morphology. Furthermore, the gene expression of integrin β1 (i.e., a cell-matrix adhesion molecule) was significantly up-regulated on the chitosan coatings with higher DD, which supports favorable attachment of corneal keratocytes. Our findings suggest that DD-mediated physicochemical properties of chitosan coatings greatly affect cell-substrate crosstalk during corneal keratocyte cultivation.

The production of fully deacetylated chitosan by compression method

Chitosan’s activities are significantly affected by degree of deacetylation (DDA), while fully deacetylated chitosan is difficult to produce in a large scale. Therefore, this paper introduces a compression method for preparing 100% deacetylated chitosan with less environmental pollution. The product is characterized by XRD, FT-IR, UV and HPLC. The 100% fully deacetylated chitosan is produced in low-concentration alkali and high-pressure conditions, which only requires 15% alkali solution and 1:10 chitosan powder to NaOH solution ratio under 0.11–0.12MPa for 120min. When the alkali concentration varied from 5% to 15%, the chitosan with ultra-high DDA value (up to 95%) is produced.

Extraction and characterization of chitin and chitosan from fishery waste by chemical method

Abstract After cellulose, chitin is the most widespread biopolymer available in nature. Chitin has economic value because of its biological activities, industrial and biomedical applications. There are three sources of chitin, namely crustaceans, insects and microorganism. The commercial sources of chitin are shells of crustaceans such as shrimp, crabs, lobsters and krill. In the present study, chitin has been extracted from locally available fish in Rourkela. The obtained chitin was converted into the more useful chitosan. The obtained chitin and chitosan have been characterized by using different techniques like spectral analysis, X-ray diffraction, Elemental analysis, Fourier transforms infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and Differential scanning calorimetry (DSC). XRD analysis indicated the crystalline nature of the chitin and chitosan. The FTIR patterns displayed the bands corresponding to stretching and vibration of O-H, N-H and CO bonds and conformed the formation of α -chitin. Degree of deacetylation (DD) value was calculated using elemental analysis, potentiometric titration and FTIR. Using FTIR analysis DD value was found to be 61%.

Renin inhibition activity by chitooligosaccharides

Six kinds of chitooligosaccharides (COSs) with different molecular weight (MW) and degree of deacetylation (DD) were prepared using ultrafiltration membrane reactor, and their renin inhibition modes were evaluated. All the COSs showed the renin-inhibitory activities with dose-dependent manner, and 90-COSs had the potent renin-inhibitory activity than that of 50-COSs. Among them, 90-MMWCOS (1000-5000Da) exhibits the highest activity with IC(50) value of 0.51mg/mL and acts as competitive inhibitor with K(i) value of 0.28mg/mL by Lineweaver-Burk and Dixon plots. These results indicated that DD value and MW of COSs are important factors affecting renin-inhibitory activity.

Study on Degradation Characteristics of Chitosan by Pepsin with Piezoelectric Quartz Crystal Impedance Analysis Technique

Piezoelectric quartz crystal impedance analysis technique was applied to study the chitosanolytic activity of pepsin. The method is based on the viscosity-density reduction of chitosan solution during the enzymatic degradation process. Experiments examined the time courses of the variations of motional resistance (deltaR1) for a quartz crystal. By comparing the deltaR1 response curves under different degradation conditions, the effects of pH, temperature, enzyme and substrate concentration on the chitosanolytic activity of pepsin was investigated in detail. The results suggest that the optimum pH and temperature were 4.6 and 55 degrees C, respectively. Increasing aptly the enzyme or substrate concentration was in favor of the degradation of chitosan. Moreover, the influence of the degree of deacetylation (DD) on the enzymatic degradation was studied. The result indicates that chitosan with a lower DD was easier to be degrade compared with chitosan with a higher DD. Also, it was found that there was a good linear relationship between the deltaR1 response and the DD value. The regression equation was deltaR1 = 0.058 x DD-6.795 and the correlation coefficient was 0.987.

Determination of the degree of deacetylation of chitin and chitosan by X-ray powder diffraction

A new method to determine the degree of deacetylation (DD) of α-chitin and chitosan in the range of 17–94% DD using X-ray powder diffraction (XRD) is proposed. The results were calibrated using 1H NMR spectroscopy for chitosan and FTIR for chitin, in comparison with the potentiometric titration method. The results showed a good linear correlation between the CrI 020 from XRD and the calibrated DD value. This method is found to be simple, rapid and nondestructive to the sample.

Synthesis and pH sensitivity of carboxymethyl chitosan-based polyampholyte hydrogels for protein carrier matrices

Novel polyampholyte hydrogels based on carboxymethyl chitosans (CMC) of various degree of deacetylation (DD) and substitution (DS) were prepared by crosslinking with glutaraldehyde. The hydrogel showed typical amphoteric character responding to pH of the external medium. At the isoelectric point (IEP), the hydrogel shrunk most, when the pH deviated from IEP, the swelling degree ( D s) increased. With increasing DD or DS value, the hydrogel changed from polyampholyte into polycations or polyanions, respectively. Osmotic forces and intermolecular interactions among CMC chains regulate the swelling behavior of CMC gel. The carboxymethyl chitin hydrogels were loaded with bovine blood proteins (BSA), and their release studies were performed in both the simulated gastric and intestinal pH conditions. The release was much quicker in pH 7.4 buffer than pH 1.2 solution; the release followed Fickian diffusion in the first 4 h and then steadily increased with the dissolution of the hydrogels.