Evaluation of nisin-loaded chitosan-monomethyl fumaric acid nanoparticles as a direct food additive

The Effect of Nanoscale Modification of Nisin by Different Milk-Derived Proteins on Its Physicochemical Properties and Antibacterial Activity

Nisin is used as a natural food preservative because of its broad-spectrum antimicrobial activity against Gram-positive bacteria. However, free nisin is susceptible to various factors that reduce its antimicrobial activity. Milk protein, a protein derived from milk, has self-assembly properties and is a good carrier of bioactive substances. In this study, lactoferrin-nisin nanoparticles (L-N), bovine serum albumin-nisin nanoparticles (B-N), and casein-nisin nanoparticles (C-N) were successfully prepared by a self-assembly technique, and then their properties were investigated. The studies revealed that lactoferrin (LF) and nisin formed L-N mainly through hydrophobic interactions and hydrogen bonding, and L-N had the best performance. The small particle size (29.83 ± 2.42 nm), dense reticular structure, and good thermal stability, storage stability, and emulsification of L-N laid a certain foundation for its application in food. Further bacteriostatic studies showed that L-N enhanced the bacteriostatic activity of nisin, with prominent inhibitory properties against Listeria monocytogenes, Staphylococcus aureus, and Bacillus cereus, which mainly disrupted the cell membrane of the bacteria. The above results broaden our understanding of milk protein-nisin nanoparticles, while the excellent antibacterial activity of L-N makes it promising for application as a novel food preservative, which will help to improve the bioavailability of nisin in food systems.

Multifunctional thiolated chitosan/puerarin composite hydrogels with pH/glutathione dual responsiveness for potential drug carriers

Puerarin (PUE), a natural and biologically active isoflavone extracted from Chinese medicine Pueraria lobata, can self-assemble to form a hydrogel without other chemical modifications. However, although PUE hydrogel has pH responsivity, but it is difficult to adapt to the changeable pathological environment. Therefore, thiolated chitosan (TCS) is synthesized and hybridized with PUE hydrogel to prepare TCS10/PUE composite hydrogel. The results of rheological measurement showed that the resultant composite hydrogels inherited the low loss performance of TCS hydrogel, which means that they have stronger elasticity. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images displayed that TCS10/PUE composite hydrogel has a fibrous-network structure. X-Ray Diffractometer (XRD) and Fourier transform infrared spectroscopy (FT-IR) proved the existence of hydrogen bonds and disulfide bonds in the formation of composite hydrogel. Degradation experiment showed that TCS10/PUE composite hydrogels have pH and glutathione (pH/GSH) dual sensitivity. Furthermore, TCS10/PUE composite hydrogels exhibited multi-functionality including thixotropy, cytocompatibility, antibacterial and anti-inflammatory properties. Berberine chloride hydrate (BCH) was further used as a model drug for in vitro release study. BCH and PUE could be released cooperatively under pH/GSH dual responsivity. These results indicated that the resultant composite hydrogel has eminent pH/GSH dual responsivity and could act as a potential new intelligent drug carrier.

Elaboration and characterization of ε-polylysine‑sodium alginate nanoparticles for sustained antimicrobial activity

The ε-polylysine (ε-PL) is a food-grade antimicrobial substance. The cationic ε-PL molecules may interact with anionic components of food matrix causing turbidity, sedimentation, and hampering the antimicrobial activity. Herein, sodium alginate (SA) was used as wall material to encapsulate ε-PL, thereby to synthesize ε-PL-SA nanoparticles (ε-PL-SA-NPs). Monosaccharide composition and molecular weight of SA were characterized. The synthetic scheme is optimized and physicochemical characteristics and antimicrobial potential was investigated. Findings indicate that SA primarily consisted of mannuronic acid (95.25 %), weight average molecular weight (Mw) of SA was 176.464 kDa, and the molecular configuration of SA was irregular line clusters. The encapsulation efficiency (EE) of ε-PL in ε-PL-SA-NPs made under optimum strategy (at pH 6.0, mass ratio of ε-PL to SA is 0.14, and SA concentration is 6 mg/mL) is about 99.74 %. The particle size of ε-PL-SA-NPs is ∼541.86 nm. The SEM image showed that the ε-PL-SA-NPs had a nearly spherical morphology. Zeta-potential and FTIR data reveal the interaction between ε-PL and SA was electrostatic and the hydrogen bonding. Agar diffusion assay exhibit that ε-PL-SA-NPs had antimicrobial activity against Escherichia coli and Staphylococcus aureus. The salmon preservation experiments reveal sustained antimicrobial efficacy of ε-PL-SA-NPs.

A novel water-soluble chitosan grafted with nerol: Synthesis, characterization and biological activity

In order to improve the antibacterial activity of chitosan and change its solubility, a novel water-soluble chitosan (CS)-nerol (N) derivative (CS-N) was prepared via Schiff base reaction and grafting reaction. FT-IR, NMR, XRD, TGA and SEM were used to characterize the structure and physicochemical properties, and in vitro antibacterial, antioxidant, and cellular assays were used to test for bioactivity and safety. The results revealed that the C6 hydroxyl group of CS was substituted with N, with a degree of substitution of 38 % for CS-N. Furthermore, compared to CS, CS-N demonstrated superior antibacterial activity against Escherichia coli and Staphylococcus aureus, as well as significant DPPH and ABTS free radical scavenging activity. Most importantly, CS-N did not harm HaCaT cells. In conclusion, this study provides a promising strategy for the design of chitosan derivatives with significant potential for application in pharmaceutical, food and cosmetic applications.

Application of functionalized chitosan in food: A review

Environmental and sustainability issues have received increasing attention in recent years. As a natural biopolymer, chitosan has been developed as a sustainable alternative to traditional chemicals such as food preservation, food processing, food packaging, and food additives due to its abundant functional groups and excellent biological functions. This review analyzes and summarizes the unique properties of chitosan, with a particular focus on the mechanism of action for its antibacterial and antioxidant properties. This provides a lot of information for the preparation and application of chitosan-based antibacterial and antioxidant composites. In addition, chitosan is modified by physical, chemical and biological modifications to obtain a variety of functionalized chitosan-based materials. The modification not only improves the physicochemical properties of chitosan, but also enables it to have different functions and effects, showing promising applications in multifunctional fields such as food processing, food packaging, and food ingredients. In the current review, applications, challenges, and future perspectives of functionalized chitosan in food will be discussed.

Composition, Properties, and Utilization of Fumaric Acid Sludge By-Produced from Industrial Phthalic Anhydride Wastewater Treatment

To understand fumaric acid sludge (FAS) systematically and comprehensively and find out how to utilize it, we conducted a series of characterization analyses on FAS. Fourier transform infrared (FT-IR) Spectra shows that the main component of FAS is fumaric acids and also contains a small amount of silicate. The nuclear magnetic resonance hydrogen (¹H-NMR) spectrum also shows that fumaric acid accounted for a large proportion of FAS. The X-ray diffraction (XRD) shows that the main phase in FAS is fumaric acid, and there is also a small amount of Kaliophilite. After gas chromatography and mass spectrometry (GC-MS) and pyrolysis gas chromatography and mass spectrometry (Py-GC-MS) analysis, it indicates that the possible volatiles and pyrolysis products in FAS are fumaric acid, maleic acid, maleic anhydride, phthalic acid, etc. In the test of Liquid chromatography and mass spectrometry (LC-MS), we determined the contents of phthalic acid, fumaric acid, and maleic acid in FAS. The detailed mass content of each component in FAS is as follows: phthalic acid is about 0.10-0.15%; maleic anhydride is about 0.40-0.80%; maleic acid is about 18.40-19.0%; fumaric acid is about 55.00-56.90%; succinic anhydride is about 0.06-0.08%; acrylic acid is about 0.06-0.08%; malic acid is about 0.90-1.00%; acetic acid is about 0.10-0.20%; silicate is about 0.25-0.30%; phthalic anhydride is about 0.20-0.30%; water is about 24.30-24.80%. The filtrate loss reducer (PAAF) used in oilwell drilling fluids synthesized by FAS not only has excellent temperature and complex saline resistance, the API filtration loss (FL) was only 13.2 mL/30 min in the complex saline based mud, but is also cost-effective.

Elaboration of Cationic Soluble Soybean Polysaccharides-Epigallocatechin Gallate Nanoparticles with Sustained Antioxidant and Antimicrobial Activities

Epigallocatechin gallate (EGCG) is easily oxidized by environmental stress elements, including light, heat, and oxygen; thus, its biological activities can be reduced or even lost when exposed to a natural environment. Here, soluble soybean polysaccharide (SSPS) was successfully etherized by 3-chloro-2-hydroxypropyl trimethylammonium chloride (CHPTAC), positively charged to extract cationic SSPS (CSSPS). Nanoparticles based on CSSPS can improve the encapsulation efficiency (EE) and sustained bioactivity of EGCG. The EE of EGCG by CSSPS was improved significantly as compared with that of SSPS due to the electrostatic interactions. Furthermore, the protective and sustained-release effects of CSSPS on EGCG in the EGCG-CSSPS nanoparticles (EGCG-CSSPS-NPs) markedly improved the sustained antioxidant and antimicrobial activities of EGCG, which was confirmed by the results of a salmon-preservation experiment. In addition, cytotoxicity tests showed that EGCG-CSSPS-NPs could effectively inhibit the proliferation of tumor cells but had no obvious toxicity to normal cells.

Matrix Isolation Study of Fumaric and Maleic Acids in Solid Nitrogen

Fumaric and maleic acids ((E)- and (Z)-HOOC-CH═CH-COOH, FA and MA) were studied experimentally by infrared spectroscopy in nitrogen matrixes and theoretically by quantum chemical calculations. The calculations, carried out at the DFT(B3LYP) and MP2 levels of theory, predicted the existence of at least 5 conformers of maleic acid and 10 conformers of fumaric acid. After the deposition of the matrixes, two conformers of maleic acid (I and II) and three conformers (I-III) of fumaric acid were observed and characterized vibrationally. Selective narrowband near-infrared (NIR) excitation of the first OH stretching overtones of the different conformers of maleic and fumaric acids initially present in the matrixes allowed the generation of higher-energy forms, never before observed experimentally. In the case of maleic acid, conformers I (a cis-trans form, where cis and trans designate the conformation of the carboxylic groups of the molecule) and II (cis-cis) were found to generate the novel conformers VI (trans-trans) and VII (cis-trans), respectively. The conversion of conformer II into the most stable conformer I was also observed. For fumaric acid, the cis-cis conformers I-III were found to give rise to the new cis-trans conformers IV-VII, respectively. The tunneling decay of the new conformers produced upon NIR excitation of the lowest-energy conformers initially trapped in the matrixes was observed, and their lifetimes in solid N₂ were determined. The increased stability of all of the observed high-energy conformers of the studied acids in the N₂ matrix, compared to the argon matrix, where they could not be observed experimentally, demonstrates the stabilizing effect of the interaction between the OH groups of the acids with the matrix N₂ molecules, in line with previous observations for other carboxylic acids. In addition, the photochemistry of matrix-isolated maleic and fumaric acids upon broad-band UV irradiation (λ > 235 nm) was also investigated. UV-induced isomerization of both acids around the C═C double bond was observed, together with their decarboxylation to acrylic acid.

Synthesis and Weak Hydrogelling Properties of a Salt Resistance Copolymer Based on Fumaric Acid Sludge and Its Application in Oil Well Drilling Fluids

Fumaric acid sludge (FAS) by-produced from phthalic anhydride production wastewater treatment contains a large amount of refractory organic compounds with a complex composition, which will cause environmental pollution unless it is treated in a deep, harmless manner. FAS included saturated carboxylic acid, more than 60%, and unsaturated carboxylic acid, close to 30%, which accounted for the total mass of dry sludge. A new oil well drilling fluid filtrate loss reducer, poly(AM-AMPS-FAS) (PAAF), was synthesized by copolymerizing FAS with acrylamide (AM) and 2-acrylamide-2-methyl propane sulfonic acid (AMPS). Without a refining requirement for FAS, it can be used as a polymerizable free radical monomer for the synthesis of PAAF after a simple drying process. The copolymer PAAF synthesis process was studied, and the optimal monomer mass ratio was determined to be AM:AMPS:FAS = 1:1:1. The temperature resistance of the synthesized PAAF was significantly improved when 5% sodium silicate was added as a cross-linking agent. The structural characterization and evaluation of temperature and complex saline resistance performance of PAAF were carried out. The FT-IR results show that the structure of PAAF contained amide groups and sulfonic acid groups. The TGA results show that PAAF has good temperature resistance. As an oilfield filtrate loss reducer, the cost-effective copolymer PAAF not only has excellent temperature and complex saline resistance, the API filtration loss (FL) was only 13.2 mL/30 min after 16 h of hot rolling and aging at 150 °C in the complex saline-based mud, which is smaller compared with other filtrate loss reducer copolymers, but it also has little effect on the rheological properties of drilling fluid.

Poloxamer188-based nanoparticles improve the anti-oxidation and anti-degradation of curcumin

Curcumin (CUR) is a food additive approved by World Health Organization. But the shortcomings, such as poor water solubility, easy oxidation and degradation, limit its application. In this study, the CUR-loaded poloxamer₁₈₈-based nanoparticles (CUR/PTT NPs) were fabricated to improve the stability and water solubility of CUR. Studies found the spherical CUR/PTT NPs had an average size of 98.71 ± 0.64 nm. Stability experiments displayed CUR/PTT NPs were extremely stable in different conditions. XRD analysis indicated the changes of crystal structures of CUR might be the main cause of the improved water solubility. Reducing power and anti-degradation tests suggested CUR/PTT NPs could improve the anti-oxidation and anti-degradation of CUR. Additionally, the results of body weight gains, hematological examination, organ coefficients, hematoxylin and eosin staining demonstrated CUR/PTT NPs bearing the excellent in vivo bio-security. Therefore, this study may provide a new idea for the combination of food industry and nanoparticles.

A Systematic Review on Nanoencapsulation Natural Antimicrobials in Foods: In Vitro versus In Situ Evaluation, Mechanisms of Action and Implications on Physical-Chemical Quality

Natural antimicrobials (NA) have stood out in the last decade due to the growing demand for reducing chemical preservatives in food. Once solubility, stability, and changes in sensory attributes could limit their applications in foods, several studies were published suggesting micro-/nanoencapsulation to overcome such challenges. Thus, for our systematic review the Science Direct, Web of Science, Scopus, and Pub Med databases were chosen to recover papers published from 2010 to 2020. After reviewing all titles/abstracts and keywords for the full-text papers, key data were extracted and synthesized. The systematic review proposed to compare the antimicrobial efficacy between nanoencapsulated NA (nNA) and its free form in vitro and in situ studies, since although in vitro studies are often used in studies, they present characteristics and properties that are different from those found in foods; providing a comprehensive understanding of primary mechanisms of action of the nNA in foods; and analyzing the effects on quality parameters of foods. Essential oils and nanoemulsions (10.9–100 nm) have received significant attention and showed higher antimicrobial efficacy without sensory impairments compared to free NA. Regarding nNA mechanisms: (i) nanoencapsulation provides a slow-prolonged release to promote antimicrobial action over time, and (ii) prevents interactions with food constituents that in turn impair antimicrobial action. Besides in vitro antifungal and antibacterial, nNA also demonstrated antioxidant activity—potential to shelf life extension in food. However, of the studies involving nanoencapsulated natural antimicrobials used in this review, little attention was placed on proximate composition, sensory, and rheological evaluation. We encourage further in situ studies once data differ from in vitro assay, suggesting food matrix greatly influences NA mechanisms.

Fish Loss/Waste and Low-Value Fish Challenges: State of Art, Advances, and Perspectives

The sustainability of fishery is a global challenge due to overfishing and reduced stocks all over the world; one of the leading factors of this threat is fish loss/waste. As a contribution to the global efforts towards a sustainable world, this review addresses the topic from different sides and proposes an overview of biorefinery approaches by discussing bioactive compounds that could be produced from fish loss (nitrogen compounds, lipids, minerals and pigments, and fish-based compounds such as chitosan). The second part of this review reports on the possibility of using loss or unwanted fish to design products for human consumption or for animal feeding, with a focus on economic criteria, consumers’ segmentation, and some examples of products. The final focus is on Food and Agriculture Organization FAO guidelines as a roadmap for the future with respect to solving this threat by addressing the problem from different sides (technology, skills, market, policy, social and gender equity, and infrastructures).

Chlorin e6 conjugated chitosan as an efficient photoantimicrobial agent

The development of antibacterial agents with high bacteria-binding capability and antibacterial efficiency is highly desirable. Herein, cationic polysaccharide chitosan (CS) was combined with photosensitizer Chlorin e6 (Ce6) to construct a novel photodynamic antibacterial agent (CS-Ce6 conjugates) for combating gram-positive bacteria Staphylococcus aureus (S. aureus) and gram-negative bacteria Escherichia coli (E. coli). CS-Ce6 conjugates with different degrees of substitution (DS) were synthesized and characterized by a spectroscopic method and organic elemental analysis to understand the relationship between structure and antibacterial effect. CS-Ce6 conjugates revealed good reactive oxygen species (ROS) generation ability and photodynamic antibacterial effect. Meanwhile, they both were positively correlated with DS in the range of 4.81% ~ 11.56% resulting in stronger photodynamic antibacterial ability. These findings highlight that CS-Ce6 conjugates have the potential as an effective photodynamic bactericidal agent in the antibacterial field.

Elaboration and characterization of curcumin-loaded soy soluble polysaccharide (SSPS)-based nanocarriers mediated by antimicrobial peptide nisin

Curcumin was recently attracted great interest owing to its multiple bioactivities; however, the use of curcumin was hindered by its poor solubility and stability. In this study, curcumin-nisin-soy soluble polysaccharide nanoparticles (Cur-Nisin-SSPS-NPs, size = 118.76 nm) have been successfully elaborated to improve the application of curcumin. The formation of Cur-Nisin-SSPS-NPs was mediated by amphiphilic and positively charged nisin: SSPS encapsulated nisin, which was mainly driven by electrostatic attraction. And nisin-SSPS complex encapsulated curcumin mainly through hydrophobic interactions between nisin and curcumin. The encapsulation efficiency of curcumin (91.66%) in this novel nanocarriers was significantly higher than that in nanoparticles prepared by a single SSPS (31.82%) or nisin (41.69%), most likely because more hydrophobic regions of nisin were exposed after interacting with SSPS through electrostatic interaction. Consequently, this facile and green nanocarriers improved the solubility/dispersibility and stability of curcumin and nisin, as well as endowed SSPS-based nanoparticles with antioxidant and antimicrobial activities.

Potential Novel Food-Related and Biomedical Applications of Nanomaterials Combined with Bacteriocins

Bacteriocins are antimicrobial peptides or proteinaceous materials produced by bacteria against pathogens. These molecules have high efficiency and specificity and are equipped with many properties useful in food-related applications, such as food preservatives and additives, as well as biomedical applications, such as serving as alternatives to current antibacterial, antiviral, anticancer, and antibiofilm agents. Despite their advantages as alternative therapeutics over existing strategies, several limitations of bacteriocins, such as the high cost of isolation and purification, narrow spectrum of activity, low stability and solubility, and easy enzymatic degradation, need to be improved. Nanomaterials are promising agents in many biological applications. They are widely used in the conjugation or decoration of bacteriocins to augment the activity of bacteriocins or reduce problems related to their use in biomedical applications. Therefore, bacteriocins combined with nanomaterials have emerged as promising molecules that can be used in various biomedical applications. This review highlights the features of bacteriocins and their limitations in biomedical applications and provides a detailed overview of the uses of different nanomaterials in improving the limitations. Our review focuses on the potential applications of nanomaterials combined with bacteriocins as new designer molecules for use in future therapeutic strategies.

Agricultural and Biomedical Applications of Chitosan-Based Nanomaterials

Chitosan has emerged as a biodegradable, nontoxic polymer with multiple beneficial applications in the agricultural and biomedical sectors. As nanotechnology has evolved as a promising field, researchers have incorporated chitosan-based nanomaterials in a variety of products to enhance their efficacy and biocompatibility. Moreover, due to its inherent antimicrobial and chelating properties, and the availability of modifiable functional groups, chitosan nanoparticles were also directly used in a variety of applications. In this review, the use of chitosan-based nanomaterials in agricultural and biomedical fields related to the management of abiotic stress in plants, water availability for crops, controlling foodborne pathogens, and cancer photothermal therapy is discussed, with some insights into the possible mechanisms of action. Additionally, the toxicity arising from the accumulation of these nanomaterials in biological systems and future research avenues that had gained limited attention from the scientific community are discussed here. Overall, chitosan-based nanomaterials show promising characteristics for sustainable agricultural practices and effective healthcare in an eco-friendly manner.

Chitosan: Structural modification, biological activity and application

Many by-products that are harmful to the environment and human health are generated during food processing. However, these wastes are often potential resources with high-added value. For example, crustacean waste contains large amounts of chitin. Chitin is one of the most abundant polysaccharides in natural macromolecules, and is a typical component of crustaceans, mollusks, insect exoskeleton and fungal cell walls. Chitosan is prepared by deacetylation of chitin and a copolymer of D-glucosamine and N-acetyl-D-glucosamine through β-(1 → 4)-glycosidic bonds. Chitosan has better solubility, biocompatibility and degradability compared with chitin. This review introduces the preparation, physicochemical properties, chemical and physical modification methods of chitosan, which could help us understand its biological activities and applications. According to the latest reports, the antibacterial activity, antioxidant, immune and antitumor activities of chitosan and its derivatives are summarized. Simultaneously, the various applications of chitosan and its derivatives are reviewed, including food, chemical, textile, medical and health, and functional materials. Finally, some insights into its future potential are provided, including novel modification methods, directional modification according to structure-activity relationship, activity and application development direction, etc.

Designing soluble soybean polysaccharides-based nanoparticles to improve sustained antimicrobial activity of nisin

Nisin is a natural antimicrobial agent and food-grade material, while the poor stability and short duration of antimicrobial activity limit its widespread use in the food industry. In the present work, soluble soybean polysaccharide (SSPS)-based nanoparticles have been developed to improve the stability and sustained antimicrobial activity of nisin. The encapsulation efficiency (EE) of nisin-loaded SSPS nanoparticles (Nisin-SSPS-NPs) prepared under the optimized conditions can be up to 99.8%, and the particle size is about 112 nm. The formation of Nisin-SSPS-NPs was mainly mediated by the electrostatic interactions and hydrogen bonding, which was evidenced by the results of zeta potential and Fourier Transform infrared spectroscopy (FTIR). Agar diffusion assay exhibited that Nisin-SSPS-NPs had confirmed antimicrobial activity against Gram-positive bacteria, such as Listeria monocytogenes, Bacillus subtilis, and Staphylococcus aureus. The sustained release of nisin in Nisin-SSPS-NPs endows nisin with a long-lasting antimicrobial activity, which increases the shelf-life of the fresh tomato juice.

Organic acids as antimicrobial food agents: applications and microbial productions

Food safety is a global health and socioeconomic concern since many people still suffer from various acute and life-long diseases, which are caused by consumption of unsafe food. Therefore, ensuring safety of the food is one of the most essential issues in the food industry, which needs to be considered during not only food composition formulation but also handling and storage. For safety purpose, various chemical preservatives have been used so far in the foods. Recently, there has been renewed interest in replacing chemically originated food safety compounds with natural ones in the industry, which can also serve as antimicrobial agents. Among these natural compounds, organic acids possess the major portion. Therefore, in this paper, it is aimed to review and compile the applications, effectiveness, and microbial productions of various widely used organic acids as antimicrobial agents in the food industry.

Influence of Chitosan Addition on Resorcinol–Formaldehyde Xerogel Structure

Gels are usually not environment-friendly due to their difficult biodegradability. Therefore, the addition of chitosan, even in small amounts, will make such gels biodegradable and thus can be useful in many applications that require environment-friendly materials. The addition of small quantities of chitosan to the reacting solution resorcinol–formaldehyde xerogel was investigated. Different hybrid resorcinol–formaldehyde–chitosan xerogels were characterized by different techniques, including Raman spectra, FTIR, XRD, TGA, SEM, surface area and porosity analyzer, and CHNS/O microanalyzer. It was seen that the addition of chitosan, even in a minor quantity, has a significant influence on the structural features of the resulting xerogels. The lattice order and crystallinity, chemical functions, thermal stability, morphology, elemental ratio, pore structure, and appearance were changed by adding chitosan into the xerogel structure.

Chitin and Chitosans: Characteristics, Eco-Friendly Processes, and Applications in Cosmetic Science

Huge amounts of chitin and chitosans can be found in the biosphere as important constituents of the exoskeleton of many organisms and as waste by worldwide seafood companies. Presently, politicians, environmentalists, and industrialists encourage the use of these marine polysaccharides as a renewable source developed by alternative eco-friendly processes, especially in the production of regular cosmetics. The aim of this review is to outline the physicochemical and biological properties and the different bioextraction methods of chitin and chitosan sources, focusing on enzymatic deproteinization, bacteria fermentation, and enzymatic deacetylation methods. Thanks to their biodegradability, non-toxicity, biocompatibility, and bioactivity, the applications of these marine polymers are widely used in the contemporary manufacturing of biomedical and pharmaceutical products. In the end, advanced cosmetics based on chitin and chitosans are presented, analyzing different therapeutic aspects regarding skin, hair, nail, and oral care. The innovative formulations described can be considered excellent candidates for the prevention and treatment of several diseases associated with different body anatomical sectors.

Development of antimicrobial edible coating based on modified chitosan for the improvement of strawberries shelf life

Edible antimicrobial coating produced from chitosan (CS) and its derivative was applied to improve the shelf life of fresh strawberries at 10 °C. Fruits treated with coating solution was stored at 10 °C and evaluated for weight loss, visual decay and microbiological analysis. Results indicated that the percentage weight loss and the decay were significantly (p < 0.05) lower for chitosan-monomethyl fumaric acid (CS-MFA) than that of CS and control samples. The total aerobic count for CS-MFA was 3.32 log CFU/fruit and was considerably lowered (p < 0.05) than CS (3.83 log CFU/fruit) and control (5.31 log CFU/fruit) at the end of storage. Fruit coated with CS-MFA showed significantly lowered (p < 0.05) count of yeast and molds when compared with CS. In conclusion, the antimicrobial edible coating based on modified CS improved microbiological characteristics and increased the shelf life from 4 (control) to 8 days (coated fruits).

Pharmaceutical applications of chitosan

Chitosan (CS) is a linear polysaccharide which is achieved by deacetylation of chitin, which is the second most plentiful compound in nature, after cellulose. It is a linear copolymer of β-(1 → 4)-linked 2-acetamido-2-deoxy-β-d-glucopyranose and 2-amino-2-deoxy-β-d-glucopyranose. It has appreciated properties such as biocompatibility, biodegradability, hydrophilicity, nontoxicity, high bioavailability, simplicity of modification, favorable permselectivity of water, outstanding chemical resistance, capability to form films, gels, nanoparticles, microparticles and beads as well as affinity to metals, proteins and dyes. Also, the biodegradable CS is broken down in the human body to safe compounds (amino sugars) which are easily absorbed. At present, CS and its derivatives are broadly investigated in numerous pharmaceutical and medical applications including drug/gene delivery, wound dressings, implants, contact lenses, tissue engineering and cell encapsulation. Besides, CS has several OH and NH₂ functional groups which allow protein binding. CS with a deacetylation degree of ~50% is soluble in aqueous acidic environment. While CS is dissolved in acidic medium, its amino groups in the polymeric chains are protonated and it becomes cationic which allows its strong interaction with different kinds of molecules. It is believed that this positive charge is responsible for the antimicrobial activity of CS through the interaction with the negatively charged cell membranes of microorganisms. This review presents properties and numerous applications of chitosan-based compounds in drug delivery, gene delivery, cell encapsulation, protein binding, tissue engineering, preparation of implants and contact lenses, wound healing, bioimaging, antimicrobial food additives, antibacterial food packaging materials and antibacterial textiles. Moreover, some recent molecular dynamics simulations accomplished on the pharmaceutical applications of chitosan were presented.

Evaluation of the efficacy of nisin-loaded chitosan nanoparticles against foodborne pathogens in orange juice

The current study aimed to fabricate nisin-loaded chitosan (N-CS) nanoparticles through ionic interactions between positive amino groups of chitosan and negatively charged tripolyphosphate ions in the presence of nisin and to evaluate their efficacy against foodborne pathogens in orange juice. The synthesized nanoparticles were sphere-shaped and homogenous with an average size of 64.34 ± 2.1 and 147.93 ± 2.9 for chitosan and N-CS nanoparticles, respectively. The encapsulation efficiency of nisin into nanoparticles was 67.32 ± 0.63%. Both chitosan and N-CS nanoparticles showed greater stability, as indicated by a higher zeta potential value of + 49.3 and + 33.4 mV, respectively. The in vitro antibacterial activities of chitosan and N-CS nanoparticles were investigated against the Gram-positive bacteria Staphylococcus aureus and Listeria monocytogenes and the Gram-negative bacteria Escherichia coli O157:H7 and Salmonella Typhimurium. N-CS nanoparticles showed higher activity compared with chitosan nanoparticles. The highest reduction of microorganisms was recorded for S. aureus of 3.82 log CFU/ml and L. monocytogenes of 3.61 log CFU/ml. The antimicrobial activity of N-CS nanoparticles in orange juice for 48 h revealed higher activity compared with the control against all the tested strains. The highest microbial reduction was recorded for N-CS nanoparticles against S. aureus with a 3.84 log CFU/ml reduction. L. monocytogenes and E. coli 0157:H7 were reduced by 3.54 and 3.44 log CFU/ml, respectively. The results showed high potential for the N-CS nanoparticles to be used as potent antibacterial agents in food and other related areas.