Search Results (128)

This study developed chitosan-based active edible coating formulations with antioxidant and antimicrobial properties exhibited by oregano and cinnamon leaf essential oils (EOs) to extend the shelf life of fresh-cut ‘Braeburn’ apples. The primary coating consisted of chitosan (1.5% w/v), ascorbic acid (2% w/v), and citric acid (2% w/v). Oregano (0.06 and 0.15% v/v) and cinnamon leaf (0.06 and 0.1% v/v) EOs were added to the primary coating. The coated apple slices were stored for 9 days at 4 ± 1 °C. Changes in weight loss, water activity, titratable acidity, total soluble solids content, polyphenol oxidase (PPO) activity, firmness, colour, visual appearance, surface morphology, and microbial activity were measured on days 2 and 9. The results revealed that the control samples deteriorated rapidly during storage. However, higher concentrations of EOs reduced moisture loss, water activity, and acid conversion but slightly impacted visual appearance. The coatings effectively inhibited the PPO activity through storage. The formulation with 0.1% cinnamon leaf EO may be considered a viable candidate for application as a coating material, followed by the formulation containing 0.06% oregano EO, maintaining the optimum quality parameters of fresh-cut apples. Chitosan-based coatings with added EOs can be a promising alternative for maintaining fresh-cut apple quality during storage. Full article

Natural organic matter (NOM) in surface waters is a major challenge for drinking water treatment due to its role in the formation of disinfection byproducts (DBPs) during chlorination. This study evaluated the performance of chitosan, a biodegradable coagulant, dissolved in acetic, lactic, and L-ascorbic acids for NOM removal under three turbidity levels (403, 1220, and 5038 NTU). Jar tests were conducted using raw water from the Río Grande de Añasco (Puerto Rico), and TOC, DOC, and UV₂₅₄ were measured at multiple time points. TOC removal ranged from 39.8% to 74.3%, with the highest performance observed in high-turbidity water treated with chitosan–L-ascorbic acid. DOC and UV₂₅₄ reductions followed similar trends, with maximum removals of 76.4% and 76.2%, respectively. Estimated THM formation potential (THMFP) was reduced by up to 81.6%. Across all acids, flocculation efficiencies exceeded 95%. Compared to conventional aluminum-based coagulants, chitosan demonstrated comparable performance, while offering environmental benefits. These results confirm the potential of chitosan–acid systems for effective organic matter removal and DBP control, supporting their application as sustainable alternatives in drinking water treatment. Full article

The BRCA-1 protein, recognized for its diagnostic relevance in a wide spectrum of malignancies, has been the focus of extensive investigation. In this study, an electrochemical immunosensor specifically designed for BRCA-1 detection was fabricated. The sensing platform utilizes disposable pencil graphite electrodes modified with a nanocomposite composed of gold nanoparticles (AuNPs), molybdenum disulfide (MoS₂), and chitosan (CS). This multifunctional nanostructure significantly promotes electron transfer efficiency and supports the effective immobilization of antibodies. The constructed immunosensor exhibited excellent analytical performance, with a linear detection range between 0.05 and 20 ng/mL for BRCA-1 and a notably low limit of detection at 0.04 ng/mL. The device maintained a relative standard deviation of 3.59% (n = 3), indicating strong reproducibility. In addition, a high recovery rate of 98 ± 3% was achieved in spiked serum samples, even in the presence of common electroactive interferents such as dopamine and ascorbic acid. These findings highlight the sensor’s promising applicability for the clinical detection of BRCA-1 and potentially other cancer-related biomarkers. Full article

The Miradero Water Treatment Plant (MWTP) in Mayagüez, Puerto Rico, uses sodium hypochlorite (SH) as a disinfectant. However, SH reacts with humic substances present in surface water, forming disinfection by-products (DBPs) regulated by the U.S. EPA. This study evaluated whether chitosan, a biopolymer with known bactericidal properties, could reduce chlorine demand and improve disinfection. Chitosan, with a 75% degree of deacetylation and a molecular weight of 460 kDa, was solubilized in four acids (acetic, citric, hydrochloric, and L-ascorbic) and tested under two turbidity ranges (236.0 and 2556 NTU). Chlorine demand curves were generated, and coliform presence–absence (P–A) tests were performed to assess bactericidal effects. Results showed that chitosan-treated samples achieved disinfection at the breakpoint with lower SH doses. For water with a turbidity of 236.0 NTU, all chitosan-acid solutions reached the breakpoint at 3.60 mg/L of SH. At 2556 NTU, three solutions required 4.20 mg/L SH, while hydrochloric acid–chitosan required only 3.60 mg/L. All chitosan-treated samples tested negative for coliforms, while controls treated with SH alone tested positive. These findings demonstrate that chitosan enhances bacterial removal and reduces chlorine demand, potentially lowering DBP formation in water treatment. Full article

Background/Objectives: The objective of this study was to develop chitosan films plasticized with glycerol for the topical delivery of ascorbic acid and metronidazole. Methods: The films were prepared using a casting technique in which an aqueous ascorbic acid solution served as the solvent, eliminating the need for additional mineral or organic acids. The influence of compositions on film characteristics—specifically mechanical properties and surface pH—was examined, and an optimized formulation was identified using a Box-Behnken design-response surface methodology. Relevant characterization techniques and in vitro evaluations were conducted to assess the properties and performance of the optimized film formulation. Results: Results showed that both glycerol and ascorbic acid contributed to the plasticization of the films. Fourier-transform infrared spectroscopic analysis of the optimized film revealed the formation of chitosan ascorbate and interactions between chitosan and glycerol. In addition, the thermogram and powder X-ray diffractogram demonstrated alterations in the thermal behavior and crystallinity of the embedded bioactive compounds. The developed film possessed the preferred swelling capacity. Moreover, in vitro release studies revealed a co-release pattern, delivering both bioactive compounds simultaneously. Conclusions: These findings suggest that the prepared chitosan-based film could serve as a promising platform for topical delivery. Full article

Plastic pollution and environmental degradation necessitate the development of natural, biodegradable food preservation materials. This study examined chitosan-based film-forming solutions using kombucha derived from black tea, lemon balm, and chamomile as natural solvents rich in bioactive compounds. Lemon balm kombucha solutions were used to create chitosan films and coat red peppers. The study assessed the mechanical properties of the films and the effects of chitosan coating on peppers, including texture, ascorbic acid content, sensory attributes, and antioxidant activity. Microbiological tests showed that a chitosan–lemon balm kombucha solution acted against Escherichia coli, Pseudomonas aeruginosa and Salmonella enterica. Lemon balm kombucha had high total phenolic (381.67 µg GAeq/mL) and flavonoid (21.05 µg Qeq/mL) contents. The chitosan film exhibited a tensile strength of 11.08 MPa and an elongation at break of 53.45%. The water vapor transmission rate of the obtained chitosan film was 131.84 g/m²·24 h. Coated peppers showed a 32% increase in skin strength and retained 11% more ascorbic acid after 15 days. Sensory evaluation revealed no significant differences from controls. These results highlight lemon balm kombucha as a promising natural solvent for chitosan coatings, which have the potential to extend red pepper shelf life and to support food preservation. Full article

Background: Captopril (CAP), an angiotensin-converting enzyme inhibitor (ACEI), is widely prescribed for managing hypertension, heart failure, and related conditions. When administered orally, CAP undergoes hepatic metabolism, resulting in a bioavailability of 60–75%. However, to bypass the first-pass metabolism and other limitations of the oral route, mucoadhesive buccal films have gained attention as a promising alternative with several advantages. The aim of this work was the formulation and optimization of chitosan-ascorbate mucoadhesive films for buccal delivery of CAP for the management of a hypertension crisis (10 mg and 20 mg) by employing quality by design (QbD) principles and the design of experiment (DoE) approach. Materials and methods: In the present work, chitosan (CHI) was selected as a film-forming agent due to its permeability-enhancing properties, which could be further improved through salification with ascorbic acid (AA). The polymer films were prepared by the solvent casting method. Results: The optimized CAP-loaded formula showed appropriate in vitro mucoadhesion force (>15 N) and breaking hardness (>14 N). The different CAP-containing films had a high drug content (>95%) with homogeneous drug distribution, thus complying with the requirements of Pharmacopeia. FT-IR and RAMAN spectroscopy analyses demonstrated successful incorporation of the drug, and interaction was observed between the excipients of the films, especially in the form of hydrogen bonds. The dissolution test showed immediate release of the API with a similar release pattern from both concentrations of CAP-loaded films. Conclusions: The properties of the prepared films met the predetermined critical quality attribute requirements. The optimized formula of CHI 1.4%, AA 2.5%, and glycerol 0.3% appears to be a promising buccal drug delivery system for CAP. Full article

In this work, the development of screen-printed electrodes modified with chitosan-coated magnetite nanoparticles (CTS@Fe₃O₄/SPGNE) for the simultaneous determination of nitrite (NO₂⁻) and ascorbic acid (AA⁻) is presented. The study investigated various ratios of graphene to chitosan-coated magnetite nanoparticles (CTS@Fe₃O₄), as well as the optimal pH. These factors were examined due to their impact on the selectivity and sensitivity of the analysis. The results indicated that a graphene paste to CTS@Fe₃O₄ ratio of 16:1.0 g and a pH of 4 were optimal for the analysis of both NO₂⁻ and AA⁻. Additionally, the behavior of the proposed electrode, its analytical performance, and interference studies were thoroughly examined. Furthermore, the CTS@Fe₃O₄/SPGNE electrode shows potential for the simultaneous determination of NO₂⁻ and AA⁻ in hydroponics and fruit juice samples. Full article

Developing biodegradable complex fertilizers is crucial for sustainable agriculture to reduce the environmental impact of mineral fertilizers and enhance soil quality. This study evaluated chitosan-based hydrogel coatings for sodium alginate matrices encapsulating amino acid hydrolysates from mealworm larvae, known for their plant growth-promoting properties. The research aims to identify the potential of biopolymer matrices for producing biodegradable slow-release fertilizers and to outline future development pathways necessary for this technology to be usable in the fertilizer industry. Chitosan coatings prepared with citric acid and crosslinked with ascorbic acid optimized plant growth, while those using acetic acid negatively affected it. Water absorption and nutrient release tests showed that chitosan coatings reduced water uptake and slowed initial nutrient release compared to uncoated samples. Leaching assays confirmed controlled-release behavior, with an initial burst followed by stability, driven by alginate–chitosan interactions and ion exchange. The X-ray diffraction (XRD) analysis revealed that adding hydrolysate and chitosan increased amorphousness and reduced porosity, improving structural properties. Thermogravimetric analysis (TGA) and Fourier-transform infrared (FTIR) spectroscopy demonstrated enhanced homogeneity and the presence of chemical interactions, which led to improvements in the material’s thermal stability and chemical characteristics. Biodegradation tests indicated greater durability of chitosan-coated composites, although hydrolysate incorporation accelerated decomposition due to its acidic pH. Germination tests confirmed no phytotoxicity and highlighted the potential of biopolymeric matrices for slow nutrient release. These findings indicate the possibilities of chitosan-coated alginate matrices as sustainable fertilizers, emphasizing the importance of adjusting coating composition and hydrolysate pH for enhanced efficacy and environmental benefits. The main recommendation for future research focuses on optimizing the chitosan coating process by exploring whether adding hydrolysate to the chitosan solution can reduce diffusional losses. Additionally, investigating the use of glycerol in the alginate matrix to minimize pore size and subsequent losses during coating is suggested. Future studies should prioritize analyzing percentage losses during the crosslinking of the alginate matrix, chitosan coating, and final shell crosslinking. This pioneering research highlights the potential for encapsulating liquid fertilizers in biopolymer matrices, offering promising applications in modern sustainable agriculture, which has not been studied in other publications. Full article

Gerbera (Gerbera hybrida) is a popular cut flower on the market, so extending its vase life (VL) is an important goal in the horticultural industry. The aim of this study was to improve the freshness of gerbera cut flowers through the optimal solution (OS) and to analyze its preservation mechanism. We used chitosan (COS), calcium chloride (CaCl₂), and citric acid (CA) as the main ingredients of the vase solution and determined the OS ratio of 104 mg/L of COS, 92 mg/L of CA, and 93 mg/L of CaCl₂ using the Box–Behnken design-response surface method (BBD-RSM). Gerbera preservation results showed that the VL of the OS was 14.5 days, which was significantly longer than that of flowers maintained in the Basic Vase Solution (BVS) and the Commercial Formulation (CF) and was highly consistent with the theoretical VL of 14.57 d. Transcriptome analysis indicated that the OS might extend VL by regulating phytohormone signaling pathways, such as cytokinin and salicylic acid signaling. The qRT-PCR analysis of key candidate genes supported these findings, with significant upregulation observed in genes related to cytokinin synthesis (e.g., GhIPT1 and GhIPT9), salicylic acid signaling related to pathogen defense (e.g., GhTGA1, GhTGA4, GhNPR1, and GhRBOHA), and plant wax synthesis and stress response (e.g., GhKCS5, GhCUT1, and GhKCS6). Further, transcriptome GO-enrichment and physiological analysis showed that the OS might extend VL of Gerbera cut flowers by scavenging reactive oxygen species, including by activating the expression of genes related to oxidoreductase activity and the activities of antioxidant-system-related enzymes catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), and superoxide dismutase (SOD), while decreasing the malondialdehyde (MDA) content. These results provide valuable insights into the mechanisms underlying the extended VL of gerbera cut flowers and offer a foundation for developing more effective preservation techniques. Full article

Background/Objectives: The development of new materials incorporating bioactive molecules for tissue regeneration is a growing area of interest. The objective of this study was to develop a new complex specifically designed for bone and skin tissue engineering, combining chitosan, ascorbic acid-2-magnesium phosphate (ASAP), and β-tricalcium phosphate (β-TCP). Methods: Chitosan and the complexes chitosan/ASAP and chitosan/ASAP/β-TCP were prepared in membrane form, macerated to a particulate format, and then subjected to characterization through Fourier transform infrared (FTIR) spectroscopy, optical and scanning electron microscopy (SEM), zeta potential, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Cell viability was evaluated through a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and with fluorescein diacetate (FDA) and propidium iodide (PI) staining in stem cells obtained from deciduous teeth. Statistical analyses were performed using analysis of variance (ANOVA), followed by Tukey’s test. Results: The FTIR results indicated the characteristic bands in the chitosan group and the complexation between chitosan, ASAP, and β-TCP. Microscopic characterization revealed a polydisperse distribution of micrometric particles. Zeta potential measurements demonstrated a reduction in surface charge upon the addition of ASAP and β-TCP to the chitosan matrix. TGA and DSC analyses further indicated complexation between the three components and the successful formation of a cross-linked structure in the chitosan matrix. Stem cells cultured with the particulate biomaterials demonstrated their biocompatibility. Statistical analysis revealed a significant increase in cell viability for the chitosan/ASAP and chitosan/ASAP/β-TCP groups compared to the chitosan control. Conclusions: Therefore, the chitosan/ASAP complex demonstrated potential for skin regeneration, while the chitosan/ASAP/β-TCP formulation showed promise as a biomaterial for bone regeneration due to the presence of β-tricalcium phosphate. Full article

This study examines the potential of natural biostimulants to mitigate environmental stress and enhance growth, yield, and quality in eggplant (Solanum melongena L., cv. Black Beauty) grown in loamy sand soil. Eggplants were treated with foliar applications of ascorbic acid (AA) at 300 mg/L, chitosan (Ch) at 200 mg/L, and moringa oil (MO) at 1000 mg/L as natural biostimulants. Results indicated significant increases in plant height, branch number, leaf chlorophyll content, fruit count, and total yield per feddan (0.42 ha) with the AA, Ch, and MO treatments compared to untreated controls. Treated plants also displayed enhanced fruit characteristics, including increased weight, diameter, length, and size. Biochemical analyses revealed elevated levels of fruit dry matter, ascorbic acid content, total phenols, flavonoids, and antioxidant activity. Untreated plants, in contrast, showed significantly lower values across all measured parameters, indicating higher susceptibility to environmental stressors and reduced growth and fruit quality. These findings underscore the effectiveness of AA, Ch, and MO as biostimulants in enhancing eggplant growth, yield, and fruit quality under loamy sand conditions. Furthermore, the use of biostimulants could be extended to other crops, offering a sustainable approach to improving food security and sustainability in agricultural practices. Full article

To enhance the preservation of strawberries, a novel coating formulation was developed using chitosan (CH) and iron oxide (IO) nanoparticles (NPs) supplemented with ginger and garlic extracts and combined with varying concentrations of 1%, 2%, and 3% Fe₃O₄ NPs. The results of XRD revealed an average crystalline size of 48.1 nm for Fe₃O₄ NPs. SEM images identified Fe₃O₄ NPs as bright spots on the surface of the fruit, while FTIR confirmed their presence by detecting specific functional groups. Additional SEM analysis revealed clear visibility of CH coatings on the strawberries. Both uncoated and coated strawberry samples were stored at room temperature (27 °C), and quality parameters were systematically assessed, including weight loss, firmness, pH, titratable acidity (TA), total soluble solids (TSSs), ascorbic acid content, antioxidant activity, total reducing sugars (TRSs), total phenolic compounds (TPCs), and infection rates. The obtained weight loss was 21.6% and 6% for 1.5% CH and 3% IO with 1.5% CH, whereas the obtained infection percentage was 19.65% and 13.68% for 1.5% CH and 3% IO with 1.5% CH. As strawberries are citric fruit, 3% IO with 1.5% CH contains 55.81 mg/100 g ascorbic acid. The antioxidant activity for 1.5% CH coated was around 73.89%, whereas 3% IO with 1.5% CH showed 82.89%. The studies revealed that coated samples showed better results, whereas CH that incorporates Fe₃O₄ NP coatings appears very promising for extending the shelf life of strawberries, preserving their quality and nutritional value during storage and transportation. Full article

A hybrid alginate hydrogel–chitosan nanoparticle system suitable for biomedical applications was prepared. Chitosan (CS) was used as a matrix for the encapsulation of lavender (Lavandula angustifolia) essential oil (LEO) and Mentha (Mentha arvensis) essential oil (MEO). An aqueous solution of an acidic Natural Deep Eutectic Solvent (NADES), namely choline chloride/ascorbic acid in a 2:1 molar ratio, was used to achieve the acidic environment for the dissolution of chitosan and also played the role of the ionic gelator for the preparation of the chitosan nanoparticles (CS-NPs). The hydrodynamic diameter of the CS-MEO NPs was 130.7 nm, and the size of the CS-LEO NPs was 143.4 nm (as determined using Nanoparticle Tracking Analysis). The CS-NPs were incorporated into alginate hydrogels crosslinked with CaCl₂. The hydrogels showed significant water retention capacity (>80%) even after the swollen sample was kept in the aqueous HCl solution (pH 1.2) for 4 h, indicating a good stability of the network. The hydrogels were tested (a) for their ability to absorb dietary lipids and (b) for their antimicrobial activity against Gram-positive and Gram-negative foodborne pathogens. The antimicrobial activity of the hybrid hydrogels was comparable to that of the widely used food preservative sodium benzoate 5% w/v. Full article

Micro- and nanoparticles of chitosan and carboxymethyl chitosan were synthesized, both with and without ascorbic acid. Methods were developed to form complexes between these micro- and nanoparticles and plant proteases—ficin, papain, and bromelain. It was demonstrated that the activity of cysteine protease complexes with carboxymethyl chitosan micro- and nanoparticles was higher compared to those with chitosan micro- and nanoparticles. Additionally, the complexes of ficin, papain, and bromelain with chitosan and carboxymethyl chitosan micro- and nanoparticles synthesized in the presence of ascorbic acid exhibited greater proteolytic activity than those formed with particles prepared without ascorbic acid. Molecular docking studies revealed that the amino acid residues of ficin, papain, and bromelain primarily interact with chitosan and carboxymethyl chitosan through hydrogen bonding and hydrophobic interactions. The amino acid residues in the active sites of these enzymes participate in a complex formation, which likely contributes to the increased activity and stability of cysteine proteases in complexes with chitosan and carboxymethyl chitosan micro- and nanoparticles. Full article