Water-soluble Chitosan Solution Research Articles

Application of water soluble chitosan for vannamei shrimp (Litopenaeus vannamei) preservation at chilling temperature

Active biomolecules such as chitosan and its derivatives have a role in food products preservation due to its antimicrobial properties. The aim of this study is to determine the ability of water soluble chitosan to extend shelf life of peeled and deveined shrimp stored at the chilling temperature. This study used completely randomized design using three treatments (control, 2% chitosan solution, and 2% water soluble chitosan solution) with six replications. Samples were tested for aerobic plate count, pH, total volatile base nitrogen, and sensory (appearance, odor, and texture). Experiments on water soluble chitosan indicated number of microbes was still within the safe limit until the 6th day. This could be identified from the number of microbes which still could be accepted by consumers (< 5 x 104 colonies/gram) at the 6th day, while in the control treatment the microbial amount within the safe limit until the 3rd day. Total Volatile Base Nitrogen of water soluble chitosan treatment was 3.69 mgN/100 grams. The pH value of shrimp treated with water soluble chitosan was 6.8, while in the organoleptic test, water soluble chitosan treatment had significant difference from control (P <0.05). This research conclude that water soluble chitosan have properties that can preserve food products specially vanamei shrimp.

Study on particle size and size distribution of gold nanoparticles by TEM and SAXS

Particle size and size distribution are two of the most vital parameters of nanomaterials since their physical properties as well as applications are highly dependent on these key factors. The objective of this work is to study the particle size and size distribution of gold nanoparticles (AuNPs), which were synthesized by a simple green synthesis in HAuCl4 and water-soluble chitosan solution (WSCS). Transmission electron microscope (TEM) and small-angle X-ray scattering (SAXS) techniques were carried out to determine the particle size, size distribution and polydispersity of AuNPs. The evidences from TEM and SAXS indicated that AuNPs can be formed in spherical shape with the size in the range of 10–30 nm. From TEM, the particle sizes of the AuNPs prepared in WSC, S at the concentration of 0.02 and 0.05 mg/mL containing 0.1 mM HAuCl4 were 20.5 ± 2.1 and 21.2 ± 1.8 nm, respectively. By increasing the concentration of HAuCl4 precursor up to 0.5 mM, AuNPs exhibited a slightly larger particle size (24.4 ± 2.2 nm). The particle size, size distribution and polydispersity of AuNPs observed by TEM and SAXS were in agreement. However, AuNPs sizes from SAXS were smaller than those from TEM because only the Au core of the AuNPs was detected by X-ray scattering. In addition, the chemical structure and specific surface plasmon resonance (SPR) absorption of AuNPs were well characterized by FTIR and UV-vis spectrophotometer. The FTIR results of AuNPs implied that the stabilization of AuNPs in the WSCS was due to electrostatic interaction and steric hindrance of C=O, C–O–C, –OH, –NH2 groups. By using WSCS at concentration 0.02 and 0.05 mg/mL, the SPR absorption bands were observed at 545 and 535 nm, respectively. The TEM and SAXS results of AuNPs in this study will provide an essential basis for synthesis of metallic nanoparticles for various applications in the future.

Chitosan and water-soluble chitosan effects on refrigerated catfish fillet quality

Chitosan’s water insolubility restricts its use in some food systems. However, when treated with enzymes, a water-soluble chitosan is developed, which overcomes insolubility. The aim of this study was to evaluate the effect of chitosan and water-soluble chitosan applications on refrigerated catfish fillet quality. Fresh catfish fillets were separately vacuum tumbled with distilled water, 1% acetic acid, chitosan (0.5% in acetic acid), and water-soluble chitosan (0.5% in distilled water). Sampling was done at 0, 5, 10, 15, and 20 days. The fillets were analyzed for lipid oxidation, aerobic plate counts, yeast and mold counts, cutting force, color, and pH. Triplicate experiments were done and the data were statistically analyzed at a significance level of 0.05. Water-soluble chitosan had 86 ± 2% water solubility compared to 1.9 ± 0.2% for chitosan. Fillets treated with water-soluble chitosan solution had lipid oxidation reduced by approximately 70% compared to untreated fillets during 20 days of refrigerated storage. Chitosan treated fillets showed the highest inhibition with aerobic plate, yeast and mold counts. Initially, fillets treated with acetic acid and chitosan solutions had a more rapid decrease in hardness than those vacuum tumbled with water-soluble chitosan and distilled water. Therefore, this study showed both the advantages and limitations of applying chitosan or water-soluble chitosan for preserving catfish fillet quality during refrigerated storage.

Development of water-soluble chitosan powder and its antimicrobial effect against inoculated Listeria innocua NRRL B-33016 on shrimp

Abstract The objectives of this study were to produce water-soluble chitosan (WSC) powder and to evaluate the effect of WSC on the survival of Listeria innocua inoculated onto shrimp surfaces. WSC powder was produced using a combination of enzymatic hydrolysis, ultrafiltration, and freeze drying. WSC solutions of 0.5, 1, 3, and 5 g/100 mL concentrations were prepared by dissolving the WSC powder in water. All concentrations of the WSC solutions showed anti-L. innocua activity in vitro, with the 5 g/100 mL WSC solution reducing initial L. innocua counts by 7.43 log CFU/mL. Freshly acquired shrimp were inoculated with L. innocua to an initial concentration of 7.65 log CFU/g. The inoculated shrimp samples were separately dipped in water (control) and in the WSC solutions for 1 min. After dipping in deionized water and 0.5, 1, 3, and 5 g/100 mL WSC solutions, the L. innocua counts were reduced by 1.50, 1.99, 2.25, 3.56, and 5.34 log CFU/g, respectively. For aerobic bacteria loads (8.43 log CFU/g) including L. innocua and natural shrimp microflora, dipping in deionized water and 0.5, 1, 3, and 5 g/100 mL WSC solution resulted in 0, 0.69, 3.21, 3.71, and 4.43 log CFU/g reductions, respectively. This study demonstrated that a low viscosity (0.01–0.29 Pa s) WSC solution could be used as an antimicrobial agent to reduce microbial loads on the surface of shrimp.

Tunable core–shell particles generated from smart water-soluble chitosan seeds

A chain-like route was presented to create various core-shell particles with soft, aqueous or inorganic cores respectively. Water-soluble chitosan (WSC) gel particles were obtained through gelating the aqueous WSC solution of 0.02 g/mL at its isoelectric point. Then, polyelectrolyte complexes were formed and surrounded on the outer surfaces of WSC gel particles by immersing the particles in 2 wt% aqueous sodium alginate. Soft WSC cores in these core-shell particles disappeared after maintaining the particles in 1M HCl for 6h. The cores of obtained particles at this step became aqueous, and could be further transformed into inorganic ones via contacting the particles with copper sulfate and sodium sulfide aqueous solutions successively. The composition of the shell was verified with Fourier transform infrared spectroscopy. The formation of various core-shell particles was confirmed with digital photographic observation, thermogravimetric and fluorescence analyses. The whole process was a chain-like one and was able to stop at any stage to harvest a corresponding target.

Bioaerosol Removal from Outpatient Clinic by Vaporized Water-Soluble Chitosan

Bioaerosol is commonly present indoors, which may affect human health. In this study, the feasibility of water-soluble chitosan as a biochemical environment protestant to remove bioaerosol from the outpatient clinic was evaluated. Results indicated the predominant bacteria existed in the outpatient clinic included Klebsiella pneumoniae, Bacillus amyloliquefaciens, Corynebacterium callunae, Bacillus cereus and Moraxella sp. The minimum inhibitory concentration (MIC) and inhibition zone of water-soluble chitosan against these strains ranged from 3500-6500 ppm and 2-6 mm, respectively. When the vaporized water-soluble chitosan (500-4000 ppm) was applied in removing bioaerosol from the outpatient clinic, >90% efficiency was achieved at 50 ml/h after 4 h treatment. However, the bioaerosol removal was also attained to 90% after 50 h continuous treatment by a diluted water-soluble chitosan solution (100 ppm). Based on the cost and efficiency consideration, the bioaerosol reduction using a diluted water-soluble chitosan solution for a long-term treatment was practical. These results clearly illustrated that water-soluble chitosan has a great potential as a biochemical environment protestant to remove bioaerosol.

Effect of water-soluble chitosan on the osteoblast function in MC3T3-E1 cells

In the present study, water-soluble chitosan (WSC) was prepared by hydrolysis of chitosan with commercial α-amylase, and the effect of WSC on osteoblast function, i.e. alkaline phosphatase activity (ALP), cell viability, mineralization, and reactive oxygen species (ROS) in osteoblastic MC3T3-E1 cells was investigated. Osteoblastic MC3T3-E1 cells were cultured in various concentrations of WSC solutions (1-5 mg/mL) for designated time and then the ALP, cell viability, mineralization, and ROS in the cells were evaluated. Treatments of osteoblastic with WSC caused a significant increase in ALP, cell viability, and mineralization in osteoblastic MC3T3-E1 cells. Moreover, treatments of osteoblastic with WSC decreased ROS level in osteoblastic MC3T3-E1 cells. The results demonstrate that the WSC may reduce or prevent osteoblasts degeneration through antioxidant activity.

Microfluidic wet spinning of chitosan-alginate microfibers and encapsulation of HepG2 cells in fibers.

The successful encapsulation of human hepatocellular carcinoma (HepG2) cells would greatly assist a broad range of applications in tissue engineering. Due to the harsh conditions during standard chitosan fiber fabrication processes, encapsulation of HepG2 cells in chitosan fibers has been challenging. Here, we describe the successful wet-spinning of chitosan-alginate fibers using a coaxial flow microfluidic chip. We determined the optimal mixing conditions for generating chitosan-alginate fibers, including a 1:5 ratio of 2% (w∕w) water-soluble chitosan (WSC) solution to 2% (w∕w) alginate solution. Ratio including higher than 2% (w∕w) WSC solution increased aggregation throughout the mixture. By suspending cells in the WSC-alginate solution, we successfully fabricated HepG2 cell-laden fibers. The encapsulated HepG2 cells in the chitosan-alginate fibers were more viable than cells encapsulated in pure alginate fibers, suggesting that cross-linked chitosan provides a better environment for HepG2 cells than alginate alone. In addition, we found that the adhesion of HepG2 cells on the chitosan-alginate fiber is much better than that on the alginate fibers.

Synthesis and Physicochemical and Dynamic Mechanical Properties of a Water-Soluble Chitosan Derivative as a Biomaterial

The physicochemical and rheological properties of a water-soluble chitosan (WSC) derivative were characterized in order to facilitate its use as a novel material for biomedical applications. The WSC was prepared by conjugating glycidyltrimethylammonium chloride (GTMAC) onto chitosan chains. Varying the molar ratio of GTMAC to chitosan from 3:1 to 6:1 produced WSCs with a degree of substitution (DS) that ranged from 56% to 74%. The WSC with the highest DS was soluble in water up to concentrations of 25 g/dL at room temperature. An increase in the polymer concentration gradually increased both the pH and conductivity of the WSC solutions. The rheological properties of the WSC solutions were found to be dependent on the salt and polymer concentrations as well as the DS value. In the absence of salt, the rheological behavior of the WSC was found to be typical of that for a polyelectrolyte in the dilute solution regime. However, the addition of salt decreased the viscosity of the polymer solution due to the reduction of electrostatic repulsions by the positively charged trimethylated ammonium groups of the WSC. In the concentrated regime, the viscosity of the WSCs was found to follow a power-law expression. The lowest DS WSC had the more favorable viscoelastic properties that were attributed to its high molecular weight, as confirmed by the stress relaxation spectra and intrinsic viscosity measurements. The effect of DS on the degree of interaction between WSC and the lipid egg phosphatidylcholine was investigated by FTIR analysis. Overall, the lower DS WSC had enhanced rheological properties and was capable of engaging in stronger intermolecular physical interactions.