Degree Of Deacetylation Research Articles

Novel bioactive sponge mats composed of oxidized bacterial cellulose and chitosan-gum Arabic microcapsules loaded with cinnamon essential oil for enhancing meat preservation

Meat is prone to microbial contamination during storage, resulting in a shortened shelf life. To address this issue, absorbent preservation mats have been suggested and proven effective in slowing down the spoilage of meat. To this end, this study developed a novel bioactive sponge mat composed of oxidized bacterial cellulose (OBC) and microcapsules loaded with cinnamon essential oil (CGCM) obtained by complex coacervation of chitosan and gum Arabic. The surface charge of such microcapsules was regulated through the use of chitosan obtained from different deacetylation degrees. The physicochemical properties, antioxidant properties, and antibacterial properties of the OBC-CGCM sponge mats were investigated and their effect on meat preservation was assessed. The results concurred that the electrostatic interaction and hydrogen bonding between the CGCM and OBC sponge mat matrix led to improved thermal stability, water absorption, and tensile strength of the sponge mat. Furthermore, it demonstrated high antioxidant (reaching up to 90%) and antibacterial properties, particularly in the gas phase (up to 65%). The application of the prepared sponge mat to the preservation of meat was able to maintain the freshness and extend the shelf life of meat from 4 days to around 10 days under 4 °C, which is significantly better than that shown by commercially available preservation mats. In conclusion, the OBC-CGCM sponge mats are highly promising for meat preservation, thereby offering an attractive universal approach to constructing active biomass packaging materials.

Utilization and Applications of Chitosan Extracted from Solenocera crassicornis Exoskeleton

In marine arthropods, the largest group Crustaceans contains 30,000 species. The shells of marine crustaceans such as shrimp, crab, and lobster, contribute to pollution in coastal areas as biowaste. The crustacean shell wastes consist of approximately 8-10 % chitin, 30-65 % protein, and 10-20 % calcium. Chitosan, a natural biodegradable polymer derived from chitin, finds applications in various fields. In the present paper, the chitosan was extracted from Solenocera crassicornis shrimp shells through a three-step process, which includes demineralization, deproteinization, and deacetylation. The physicochemical properties of chitosan including ash, moisture content, degree of deacetylation, water and fat binding capacity, and solubility were analyzed. This study explored the diverse applications of chitosan, including its antimicrobial, shelf-life enhancement, anticoagulant, and wastewater treatment properties. This study concluded that chitosan can be suitable for application in various fields including medicine, cosmetology, biotechnology, the edible film industry, and water purification.

A New and Rapid HPLC Method to Determine the Degree of Deacetylation of Glutaraldehyde-Cross-Linked Chitosan.

Chitosan is a linear biopolymer composed of D-glucosamine and N-acetylglucosamine units. The percentage of D-glucosamine in the polymeric chain can vary from one sample to another and is expressed as the degree of deacetylation (DDA). Since this parameter has an impact on many properties, its determination is often critical, and potentiometric titration is a common analytical technique to measure the DDA. Cross-linking with glutaraldehyde is one of the most explored modifications of chitosan; however, the determination of the DDA for the resulting reticulated chitosan resins can be challenging. In this paper, we report a new, rapid, and efficient method to determine the DDA of glutaraldehyde-cross-linked chitosan resins via HPLC. This method relies on the use of 2,4-dinitrophenylhydrazine (DNPH) as a derivatizing agent to measure the level of reticulation of the polymer (LR) after the reticulation step. In this study, we prepare three calibration curves (with an R2 value over 0.92) for three series of reticulated polymers covering a large range of reticulation levels to demonstrate that a correlation can be established between the LR established via HPLC and the DDA obtained via titration. The polymers are derived from three different chitosan starting materials. These standard calibration curves are now used on a routine basis in our lab, and the HPLC method has allowed us to change our DDA analysis time from 20 h to 5 min.

The Tissue Browning and Concomitant Toughening of Yellow Flammulina filiformis Stipes Is Caused by Oxidative Damage-Mediated Metabolic Disorder and Cell Wall Glycan Remodeling.

The browning and associated toughening of fruiting body stipes are the main causes of declines in the commercial production of yellow Flammulina filiformis. The dynamic metabolic changes from the top to bottom stipe sections of yellow F. filiformis fruiting bodies were investigated by integrating physiological, transcriptomic, and metabolomic analyses. The results indicated that oxidative stress levels gradually increased accompanying the degree of tissue browning and toughening from the top to bottom sections of F. filiformis stipes. In-depth analysis showed that there were remarkable changes in the expression of genes, and the content of metabolites correlated with the primary and secondary metabolism of F. filiformis stipes. Interestingly, the expression levels of genes participating in chitosan biosynthesis and the degree of deacetylation of chitosan increased from top to bottom in F. filiformis stipes, implying that cell wall glycan remodeling may contribute to concomitant toughening of the browning of F. filiformis stipes.

Comprehensive characterization and evaluation of the process chain and products from Euphausia superba exocuticles to chitosan

AbstractAntarctic krill (Euphausia superba) is a source for compounds of high nutritive value. Within that process of extraction, exocuticles (shells) accumulate which are currently disposed. A valorization of the compounds of the exocuticle such as chitosan would be beneficial to avoid waste and to obtain a versatile polymer at the same time. In contrast to previous investigations focusing on chitosan production from whole krill, we applied and optimized process stages of the chitosan production from the exocuticles, performing a comprehensive analytical evaluation of the whole process, the side streams and the products for the first time. Degreasing was the first step resulting in a krill oil yield of 6.2% using ethanol. The fatty acid profile exhibited high contents of phospholipids (21.2%). Citric acid offered a demineralization efficiency of 93%. Deproteinization investigation revealed 2 M NaOH and 90°C for 2.5 h to be the best parameters, resulting in a deproteinization efficiency of 99.9% and a chitin content of 92.8%. The spectroscopic investigation indicated that the chitin has a crystallinity index of 76% and an acetylation degree of 88%. The deacetylation degrees of the resulting chitosans is determined to be 74%–88%, the molecular weight ranges from 102 to 126 kDa.

Chitosan Decelerates Melanosis in Shrimp: A Novel Technique for Visual Quality Assessment Using Digital Image Analysis

The study aimed to determine the effects of chitosan, sodium metabisulfite, and citric acid against melanosis, which causes significant economic losses during the storage of shrimps. For this purpose, two different types of chitosan were extracted from tiger prawn shell wastes. The extracted chitosan was characterized by viscosity, FT-IR, XRD, SEM imaging, and color analyses. Prevention of melanosis formation was investigated by testing chitosan, sodium metabisulfite, and citric acid. To achieve this, fresh deep-water pink shrimp samples immersed in different solutions were stored for 12 days at 4℃. Melanosis formation in the samples was observed via color measurement, sensory evaluation, and image analysis. According to the results of the research, the deacetylation degrees of chitosans were found to be 99.50 and 89.51% and 76.31 and 78.24% by two different methods, respectively. Viscosities were measured as 0.34 and 4.17 cSt, respectively. Regarding the color parameters, the L* values were 83.68 and 78.94, a* values were 0.55 and 2.71, and b* values were 10.33 and 13.85, respectively. According to the sensory evaluation conducted throughout the study, melanosis formation was observed in all groups starting from the 6th day. On the 8th day, the control groups exceeded the acceptability threshold, and on the 12th day, melanosis formation spread throughout the body in all groups. The sensory evaluation results were supported by the color measurement and image analysis implemented for the first time in this study. The present study’s results showed that chitosan obtained from shellfish wastes decelerates melanosis formation as an alternative to commercially used chemicals.

Curcumin-loaded Pickering emulsion stabilized by pH-induced self-aggregated chitosan particles: Effects of degree of deacetylation and molecular weight

Curcumin, a natural polyphenolic compound, has many health benefits: instabilities and poor solubility limit curcumin's industrial applications. The encapsulation of curcumin in Pickering emulsion can enhance its bioavailability. Developing an efficient and simple method for fabricating a natural emulsifier for Pickering emulsion remains a significant challenge. Chitosan has gained attention for its nontoxicity and excellent emulsifying properties. The purpose of this study was to prepare four different types of self-aggregated chitosan particles using a pH-responsive self-assembling method. The aggregated particle properties are tuned by pH, degree of deacetylation (DDA), and molecular weight (MW) through control of surface charge, size (nano, micro, and floc), and contact angle. Pickering emulsions were prepared using different types of aggregated particles. As MW and pH increase and DDA decreases, aggregated particles networked structures formed, resulting in highly elastic gels more resistant to the breakdown of Pickering emulsion at ambient temperature. When ramped up to higher temperatures, the kinetic energy of aggregated particles increases, disrupting hydrogen bonds and potentially changing the systems from fluids to gels. The aggregated particles-based Pickering emulsion was used as the carrier for curcumin encapsulation. MW and DDA regulate drug loading, encapsulation efficiency, and release profile. It found that DDA and MW were responsible for tuning the properties of Pickering emulsion. This research provides a new perspective on selecting suitable chitosan for controlling the release of bioactive compounds in Pickering emulsions, considering factors such as adjustable rheological properties, microstructure, and macrostructure.

Chitosan coatings with different degrees of deacetylation regulate the postharvest quality of sweet cherry through internal metabolism

In this study, chitosan coatings with different degrees of deacetylation (DD, 88.1 % and 95.2 %) were electrostatically sprayed on sweet cherries to evaluate their impacts on postharvest characteristics and internal metabolism. The results showed that chitosan coating could effectively delay the change of weight, color, firmness, and maintain the content of total phenols, flavonoids and titratable acids, and inhibit the activities of β-galactosidase and polyphenol oxidase during cold storage. The storage qualities and physiological activities of sweet cherry were significantly correlated with the contents of sorbitol, 4-hydroxycinnamic acid, hydrogenated hydroxycinnamic acid, tyrosine, proline, glutamine, phenylalanine, and other metabolites. Chitosan coating may modulate fruit quality by inhibiting the energy metabolism, accelerating the accumulation of carbohydrates, and promoting the metabolism of phenylalanine and flavonoid. Especially, chitosan coating with 88.1 % DD had better wettability on sweet cherry's peel and displayed more obvious preservation effect through stronger metabolic regulation ability.

A novel eco-friendly polymeric photosensitizer based on chitosan and flavin mononucleotide.

Flavin mononucleotide (FMN) is a dye belonging to the flavin family. These dyes produce photosensitized degradation of organic compounds via reaction with the excited states of the dye or with reactive oxygen species photogenerated from the triplet of the dye. This article presents a new polymeric dye (FMN-CS) composed of the photosensitizer FMN covalently bonded to chitosan polysaccharide (CS). FMN-CS obtained has a molecular weight of 230 × 103gmol-1 and a deacetylation degree of 74.8%. The polymeric dye is an environmentally friendly polymer with spectroscopic and physicochemical properties similar to those of FMN and CS, respectively. Moreover, under sunlight, it is capable of generating 1O2 with a quantum yield of 0.31. FMN-CS, like CS, is insoluble in basic media. This allows easy recovery of the polymeric dye once the photosensitized process has been carried out and makes FMN-CS a suitable photosensitizer for the degradation of pollutants in contaminated waters. To evaluate whether FMN-CS may be used for pollutant degradation, the photosensitized degradation of two trihydroxybenzenes by FMN-CS was studied.

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.

An influence of molecular weight, deacetylation degree of chitosan xerogels on their antimicrobial activity and cytotoxicity. Comparison of chitosan materials obtained using lactic acid and CO2 saturation

This paper presents a comparison of the antimicrobial activity and cytotoxicity against L929 cells of chitosan xerogels prepared by dissolving the polymer in a solution of lactic acid (LA) or carbonic acid (CO2) and then freeze-drying. There was no simple relationship between the antimicrobial activity and cytotoxicity of the samples obtained using both techniques (LA and CO2). Chitosan materials obtained by the LA method in a 1:1 dilution were characterized by the highest cytotoxicity against L929 cells (∼20%). For the same diluted samples prepared using the CO2 saturation method, the viability of L929 cells was approximately 2.5 times greater. Some of the tested chitosan materials obtained by the innovative method were characterized by significantly lower antimicrobial activity, for example, reduction of E. coli bacteria for MMW-LA and MMW-CO2 samples by 6.00 and 0.75 logarithmic order, respectively. This clearly indicates that in many applications, the presence of the acid necessary to dissolve chitosan is responsible for the antimicrobial activity of the polymer solution and its products.

Chemical extraction, characterization, and inspection of the antimicrobial and antibiofilm activities of shrimp chitosan against foodborne fungi and bacteria.

Nowadays, the exploitation of biopolymers in the industrial sector has become a trend. Chitosan is considered one of the most investigated biopolymers due to its abundance and antibacterial, antifungal, and antibiofilm activities. In this work, chitosan was chemically extracted from shrimp shells. Solutions of HCl 1M, NaOH 4M, and NaOH 15M were used for the demineralization, deproteinization, and deacetylation process, respectively. The utilized methods of characterization (FTIR, 1H NMR, 13C NMR, and SEC-MALS) revealed that the obtained chitosan has a moderate degree of deacetylation and low molecular weight (DDA = 74% and Mw = 72.14kDa). The microdilution method and inoculation of solid medium were carried out to assess the antibiofilm action of chitosan against Staphylococcus aureus, Pseudomonas aeruginosa, Enterococcus hirae, Escherichia coli, Rhizopus sp., and Aspergillus sp. which are known as foodborne microorganisms. Results showed that the produced chitosan at 1g/L inhibits between 63.44 and 99.75% of the microbial biofilm depending on the tested strains. These promising results confirm the potential deployment of the obtained chitosan in the food industry as a replacement for synthetic antimicrobial agents.

Chitosan Dissolution in [BMIM]Cl Ionic Liquid: An Optimisation and Bacterial Ecotoxicity Study

Chitosan is formed from chitin deacetylation, but its insolubility remains challenging for industrial applications. An alternative would be employing Ionic Liquids (ILs) as a potential green solvent to dissolve chitosan. Hence, this research aims to study the optimum conditions of chitosan-[BMIM]Cl dissolution using Response Surface Methodology (RSM) and evaluate the ecotoxicity of chitosan-[BMIM]Cl mixture against Gram-positive and Gram-negative bacteria. Chitosan was obtained from heterogenous N-deacetylation of chitin using 50% sodium hydroxide solution at 100°C for 2.5 h. Chitosan dissolution in [BMIM]Cl was optimised using Central Composite Design (CCD) via RSM based on three independent factors: temperature, initial chitosan loading and dissolution time. Ecotoxicity of chitosan-[BMIM]Cl was evaluated using broth microdilution test against Escherichia coli and Staphylococcus aureus. Chitosan with a degree of deacetylation (DD) of 83.42% was obtained after three successive alkali treatments. Fourier Transform Infrared Spectroscopy (FTIR) revealed the presence of free hydroxyl groups, additional amino groups, and reduced C=O and C-H stretch intensity, indicating successful chitin deacetylation. The regression model for chitosan dissolution in [BMIM]Cl was significant (p < 0.05) with a non-significant lack of fit (p > 0.05). The optimised conditions to dissolve chitosan in [BMIM]Cl was 130°C, 1 wt. % and 72 h with a mean relative error of 1.78% and RMSE of 5.0496 wt. %. The toxicity of 10 wt. % chitosan-[BMIM]Cl mixture was “relatively harmless” (EC50 > 1000 mg/L) with an EC50 value of 3.1 wt. % for Escherichia coli and 3.2 wt. % for Staphylococcus aureus.

Chitosan-glucose derivative as effective wall material for probiotic yeasts microencapsulation

A chitosan-glucose derivative (ChG) with lower antimicrobial activity against whey native probiotic yeast K. marxianus VM004 was synthesized by the Maillard reaction. The ChG derivative was characterized by FT-IR, 1H NMR, and SLS to determine the structure, deacetylation degree (DD), and molecular weight (Mw). In addition, we evaluated the antioxidant, cytotoxic, and antimicrobial activities of ChG. ChG was then used for microencapsulation of K. marxianus VM004 by spray drying. The microcapsules were characterized by evaluating their encapsulation yield, encapsulation efficiency, morphology, tolerance to the gastrointestinal tract, and viability during storage. The results indicated that a non-cytotoxic product with lower MW and DD and higher antioxidant activity than native chitosan was obtained by the Maillard reaction. The yeast ChG microcapsules exhibited an encapsulation efficiency >57 %, improved resistance to gastrointestinal conditions, and enhanced stability during storage. These results demonstrate that ChG may be a promising wall material for the microencapsulation of probiotic yeasts.

Physicochemical characterization of chitin extracted by different treatment sequences from an edible insect

Chitin present in the shell of edible insects is a potential source of chitin, lipids, and proteins, and it exerts various biological activities. Thus far, only a few studies have focused on the use of chitin as a source of high-protein-diet oligosaccharides. The use of insect chitin for the production of high-protein-diet oligosaccharides can lessen the reliance on diet crops. Moreover, although chitin composition in Tenebrio molitor larva, pupa, and adult has been extensively investigated, chitin extraction from T. molitor larval whole body and exuvium has received poor attention. The present study compared the effectiveness of two techniques for extracting high-protein-diet chitin oligosaccharide from an edible insect (T. molitor). Two different extraction sequences of chitin from the larval stage (molitor stage larvae) and adult stage (molitor stage adult) of edible T. molitor were investigated. Two processing steps were employed: (a) deproteinization (DEP) and (b) demineralization (DEM) treatments. Differences in the order, conditions, and period of their application resulted in two different chitin extraction procedures. The viscosity, degree of polymerization, and crystallinity index of the chitin extracted using the two procedures were measured, and its chemical components (chitin, ash, protein, fat, and moisture contents) were determined. T. molitor adults and larvae treated sequentially with DEM-DEP demonstrated the greatest yield of approximately 14.62 % ± 0.15 and 6.096 % ± 0.10 %, respectively. By contrast, when treated sequentially with DEP-DEM, the recorded yields were 10.96 % ± 0.18 and 5.31 % ± 0.38, respectively. Differences in the degree of deacetylation between both methods were observed. Additionally, Fourier transform infrared spectroscopy and X-ray diffractometry of the extracted chitin along with a commercial sample revealed consistent chain conformation, mean hydrogen bonding, and crystallinity index. In this way, residues produced by farmed edible insects can be recovered and used as a novel source of chitin.

Extraction of rare earth elements from monazite leach liquor using functionalized chitosan sorbents derived from shrimp waste

With the growing need for high-purity rare-earth elements (REEs), the separation of these REEs has received much attention recently. The objective of this research is to produce chitosan from shrimp waste, then modify it with different functionality, and investigate the adsorption properties of chitosan adsorbents towards La(III) ions. First, from shrimp waste, chitosan (ch) with a significant degree of deacetylation, purity, and solubility was produced. The purified chitosan was cross-linked with epichlorohydrin (ep), and then, it was modified with 3,6,9,12-tetraazatetradecane-1,14-diamine (HA) to produce polyaminated chitosan (HA@ep@Ch). The polycarboxylated/imine chitosan (CM@HA@ep@Ch) was obtained by treating polyaminated chitosan with chloroacetic acid in isopropyl alcohol. The chitosan adsorbents were characterized and applied for lanthanum recovery from synthetic and monazite leach liquor samples. The factors controlling the recovery process were studied and discussed. The performance of the adsorbents was achieved through equilibrium, dynamic, and isothermal studies. HA@ep@Ch and CM@HA@ep@Ch showed good performance for lanthanum recovery with a maximum capacity of 114.52 and 141.76 mg/g at 330 K, respectively. The isotherm parameters refer to the monolayer of lanthanum adsorbed into the adsorbents through chelation and ion exchange mechanisms. A 0.5-M HCl solution was found effective to elute 95.8% of the adsorbed lanthanum on HA@ep@Ch, and 93.4% of the adsorbed lanthanum on CM@HA@ep@Ch. The adsorbents showed greater selectivity in extracting La, Ce, Pr, Nd, and Sm (62–75%) from REE leach liquid compared to extracting other REEs (20–41%).

Product diversification to boost the sustainability of the shrimp processing industry: The case of shrimp-waste driven chitosan-based food Pickering emulsion stabilizers

Diversifying the product portfolio of the shrimp processing industry using its waste streams could contribute to its environmental sustainability and economic resilience. Considering that this study aimed to increase the commercial value of shrimp shell waste by using chitosan extracted from these wastes as a food emulsion stabilizer. More specifically, chitin was extracted from shrimp shell waste, and chitosan was then prepared from chitin by deacetylation. The findings showed that the extraction efficiency and degree of deacetylation of chitosan were 23% and 83%, respectively. After that, stearic acid was added to chitosan chains to improve its emulsifying properties. Then, the chitosan/stearic acid–stabilized flaxseed oil and olive oil emulsions were prepared in three oil ratios (20, 40 and 60%). The interfacial structure study showed that compared to flaxseed oil droplets, the olive oil droplets’ surface was better covered with the chitosan/stearic acid nanogels. Moreover, the rheological study indicated a stronger gel-like structure in olive oil emulsions than the flaxseed oil emulsions, particularly at 60% oil. The dried emulsions indicated that the olive oil was encapsulated better than flaxseed oil by the chitosan-based particles, and less oil leakage was observed for dried olive oil emulsions. Better encapsulation of olive oil with chitosan/stearic acid nanogels could be attributed to the higher polarity and viscosity of olive oil compared to flaxseed oil and the greater similarity of olive oil fatty acid profile with stearic acid attached to chitosan. In general, these findings showed that the stabilizer developed from shrimp shell waste is suitable for stabilizing emulsions containing more polar oils with less degree of unsaturation. The results obtained could contribute to enhancing the sustainability of the shrimp processing industry by diversifying its product portfolio.

Chitosan Polysaccharides from a Polarizable Multiscale Approach.

We report simulations of chitosan polysaccharides in the aqueous phase, at infinite dilute conditions and zero ionic strength. Those simulations are performed by means of a polarizable multiscale modeling scheme that relies on a polarizable all atom force field to model solutes and on a polarizable solvent coarse grained approach. Force field parameters are assigned only from quantum chemistry ab initio data. We simulate chitosan monomer units, dimers and 50-long chains. Regarding the 50-long chains we simulate three sets of ten randomly built chain replica at three different pH conditions (corresponding to different chain protonation states, the chain degree of deacetylation is 85%). Our simulations show the persistence length of 50-long chitosan chains at strong acidic conditions (pH <5) to be 24 ± 2 nm (at weak/negligible ionic strength conditions), and to be 1 order of magnitude shorter at usual pH conditions. Our simulation data support the most recent simulation and experimental studies devoted to chitosan polysaccharides in the aqueous phase.

Porous chitosan membranes by solvent evaporation technique: evaluation of the biopolymer/acetone ratio and potentiality for the membrane distillation process

ABSTRACT Chitosan is a biopolymer and with proper preparation conditions could be promising for membrane distillation. Based on the current environment-based initiatives, in this work, a chitosan porous membrane was synthesized. The effect of chitosan on the presence of acetone at different concentrations was evaluated and FTIR showed acetamido groups and changes in the degree of deacetylation. The membrane was characterized by water uptake, porosity, and microstructure. It presented moderate hydrophobic behavior and porosities (62%−92%) with slit-like pores. The membrane distillation demonstrated the use of membrane produced with permeate flux (16.07–51.62 kg.m−2.h−1).

Evaluation of the Antimicrobial Activity of Chitosan Nanoparticles against Listeria monocytogenes.

Chitosan is obtained from the deacetylation of chitin, and it is known to possess antimicrobial activity. It has attracted attention as it may be used for treating infections caused by different types of microorganisms due to its broad spectrum. Its application in the form of micro- or nanoparticles (CM/CN) has expanded its usage, as in this form, it retains its activity, and remain stable in aqueous solutions. However, inconsistencies in the results reported by different authors have been identified. In this communication, the antimicrobial activity of CN produced from different starting materials was tested against Listeria monocytogenes. It was observed that, even though all the starting materials were reported to have a molecular weight (MW) below 200 kDa and degree of deacetylation (DD) > 75%, the size of the CNs were significantly different (263 nm vs. 607 nm). Furthermore, these differences in sizes exerted a direct effect on the antimicrobial properties of the particles, as when testing the ones with the smallest size, i.e., 263 nm, a lower Minimum Inhibitory Concentration (MIC) was achieved, i.e., 0.04 mg/mL. Even though the largest particles, i.e., 607 nm, in individual experiments were able to achieve an MIC of 0.03 mg/mL, the results with CN presented great variation among replicates and up to 0.2 mg/mL were needed in other replicates. The starting material has a critical impact on the properties of the CN, and it must be carefully characterized and selected for the intended application, and MW and DD solely do not fully account for these properties.