Oligochitosan Research Articles

Study on the impact of chitin derivatives on the quality of pre-cooked wet alkaline noodles and antioxidant browning

In this study, the impact of chitin derivatives such as chito-oligosaccharides (COS), oligo-chitosan (OC) and poly-chitosan (PC) was examined on their ability to enhance pre-cooked wet alkaline noodles (PWAN) quality and their antioxidant browning when added to flour prior to manufacture. It was found that all chitin derivatives could reduce the water migration rate and enhance the hardness and tensile properties of PWAN. Additionally, these chitin derivatives increased α-helical structure and decreased β-turns and random coils (unstructured) components resulting in a continuous and intact gluten network. They also showed good inhibition effects on microorganisms in PWAN. Adding the three chitin derivates increased the total phenol and total flavonoid content in PWAN. COS exhibited superior scavenging activity against DPPH radicals, iron ion reducing capacity and anti-superoxide anion, while PC was more resistant to ABTS radicals. This work can provide a basis for the quality amelioration and antioxidant browning of noodles.

Discarded enoki mushroom root-derived multifunctional chrome-free chitosan-based tanning agent for eco-leathers manufacturing: Tanning-dyeing, non-acid soaking, and non-basifying

The aim of this study was to develop new discarded enoki mushroom root-derived multifunctional chrome-free chitosan-based tanning agents that can be used for eco-leather manufacturing. In this study, oligochitosan (OCS) was prepared from chitosan extracted from the enoki mushrooms and chemically modified using reactive dye R19 and epichlorohydrin (ECH) to prepare chromium-free tanning agent (OCS-R19-ECH) with both tanning and dyeing functions. FT-IR, XRD, and NMR (1H) confirmed the successful synthesis of the product. The molecular weight of OCS-R19-ECH is 6355 g/mol, with an average particle size of 1249.37 nm and an epoxy value of 0.276 mol/100 g. OCS-R19-ECH was used for tanning experiments on bated sheepskin, and the results showed that the leather tanned with OCS-R19-ECH not only exhibited excellent wet-heat stability (shrinkage temperature = 81 °C), but also superior dyeing uniformity, resistance to dry and wet abrasion, mechanical strength (tensile strength = 12.4 MPa, tear strength = 57.3 N/mm), and outstanding antimicrobial properties. Most importantly, compared with traditional tanning agents, OCS-R19-ECH has a higher pH (9.0), tanning-dyeing integration, non-acid soaking, and non-basifying can be achieved in leather making, which can greatly simplify the tanning processes. This new multifunctional chrome-free chitosan-based tanning agent facilitates high-value utilization of waste resources.

One-pot Formulation of Cationic Oligochitosan Coated Nanoparticles via Photo- Polymerization Induced Self-Assembly.

During last few decades, oligochitosan (OCS)-coated nanoparticles have received great interest for nanomedicine, food and environment applications. However, their current formulation techniques are time-consuming with multi-synthesis/purification steps and sometimes require the use of organic solvents, crosslinkers and surfactants. Herein, we report a facile and rapid one-pot synthesis of OCS-based nanoparticles using photo-initiated reversible addition fragmentation chain transfer polymerization-induced self-assembly (Photo-RAFT PISA) under UV-irradiation at room temperature. To achieve this, OCS was first functionalized by a chain transfer agent (CTA) resulting in a macromolecular chain transfer agent (OCS-CTA), which will act as a reactive electrostatic/steric stabilizer. Owing to its UV-sensitivity, OCS-CTA was then used as photo-iniferter to initiate the polymerization of 2-hydroxypropyl methacrylate (HPMA) in aqueous acidic buffer, resulting in OCS-g-PHPMA amphiphilic grafted copolymers which self-assemble into nano-objects. Transmission electron microscopy and light scattering analysis reveal formation of spherical nanostructures.

Irradiation-induced Maillard reaction with glucosamine: an advance strategy to modify chitosan

In this study, Maillard reaction with glucosamine (GA) induced by gamma irradiation was applied for chitosan (CT) and oligochitosan (OC) to improve the solution stability and antibacterial activity under alkaline condition. The mixture solutions of CT and/or OC with GA were irradiated at the dose of 25 kGy to form the Maillard reaction products (MRPs) respectively. The formations of MRPs were determined by spectrophotometric analyses at the wavelength of 284 nm and 420 nm. The improvement effect caused by the Maillard reaction on the stability of CT and OC solutions in alkaline condition was evaluated through the increase of pH value at the precipitation point of the solutions before and after irradiation. The antibacterial activity of the solutions against Escherichia coli was also investigated. The results showed that the CT-GA MRPs and OC-GA MRPs solutions could be remain their stability at pH 7, and the pH values at the precipitation point were 7.4 and 11.5 respectively. Moreover, at pH 7, the MRPs solutions exhibited high antibacterial activity with the reduction of ~ 4 log CFU/ml over control sample. Furthermore, 5-hydroxymethylfurfural (5-HMF), a known cytotoxic product formed by heat-induced Maillard reaction was not detected in both irradiated CT-GA and OC-GA solution. These results prove that the irradiation-induced Maillard reaction is an effective strategy to modify chitosan, and the MPRs of CT/OS with GA had a great potential to replace synthesis additives as a natural preservative for food applications

Binding and Specificity of Ovalbumin with Chitosan Derivatives Varying in Degree of Acetylation

Here is an insight into the interaction and formation of insoluble complexes of ovalbumine (OV) with a series of specific chitosan derivatives (oligochitosan (OCHI)), varying in the degree of acetylation (DA) in acidic, neural and alkaline media. The forces involved in the complexation are determined and discussed. As shown, the interaction is partially electrostatic by nature with the “molar” composition in the insoluble OCHI-25/OV and OCHI-31/OV complexes of 1:2.8 and 1:2.1, respectively. The interaction is also partially hydrophobic and intensified at elevated temperatures. It is found that the binding of OV to OCHI and stability of the complexes depend on the way they are formed, and the affinity of OV to OCHI weakens with the increase in the DA. The complexes formed in a slightly acidic solution are limitedly soluble at a high solution ionic strength, and the aggregative state of the complexes depends on the weight fraction of OCHI in the complexes. The finding can be useful for understanding the complexation processes of chitosan with proteins and can be promising as a platform for the preparation of ovalbumin-based vaccines.

Combined application of oligochitosan and Pichia carrbbica improves the disease resistance of postharvest tomato fruits

Our previous study showed that postharvest treatment of tomato with Pichia caribbica along with oligochitosan (OCH) significantly alleviated postharvest black spot of tomato fruit compared with P. caribbica alone. This study was to explore the effect of combined application of OCH and P. caribbica on disease resistance of tomato fruits through analyzing the activities of disease resistance-related enzymes, as well as transcriptome analysis of the fruit gene expression. Our findings indicated that P. caribbica, together with OCH, improved the activities of key enzymes associated with disease resistance in tomato fruit. Moreover, the combined application further upregulated the expression of genes involved in α-linolenic acid metabolism, the signal transduction pathways such as Ca2+, MAPK and plant hormone signaling pathways, resistant substance synthesis, and ROS metabolism, which improved the fruit disease resistance. Considering the significance of these results, OCH hold great potential for use in microbial biocontrol strategies against postharvest tomato diseases.

Preparation and properties of polyurethane film dressing modified by catechol grafted oligochitosan

In this study, carbon-carbon double bonds and catechol groups modified oligochitosan (OCS)/photocurable polyurethane composite films (OPU) were prepared for wound dressing application. Methacrylic anhydride (MA) was used to modify oligochitosan. The effect of the ratio of amino groups on OCS to MA on the properties of the composite films was investigated. The results showed that the OPU films possessed the best overall performance in hydrophilicity, mechanical strength, adhesion properties, and antibacterial activity when the ratio of amino groups on OCS to MA was 4:2. The prepared films may show potential application as wound dressings.

Effect of Soft Preheating of Bovine Serum Albumin on the Complexation with Oligochitosan: Structure and Conformation of BSA in the Complex.

Phase analysis, spectroscopic and light scattering methods are applied to investigate the peculiarities of the interaction of oligochitosan (OCHI) with native and preheated BSA as well as the conformational and structural changes of BSA in BSA/OCHI complex. As shown, untreated BSA binds with OCHI mainly forming soluble electrostatic nanocomplexes, with the binding causing an increase in BSA helicity without a change in the local tertiary structure and thermal stability of BSA. In contrast, soft preheating at 56°C enhances the complexation of BSA with OCHI and slightly destabilizes the secondary and local tertiary structures of BSA within the complex particles. Preheating at 64°C (below the irreversible stage of BSA thermodenaturation) leads to further enhancement in the complexation and formation of insoluble complexes stabilized by both Coulomb forces and hydrophobic interactions. The finding can be promising for the preparation of biodegradable BSA/chitosan-based drug delivery systems. This article is protected by copyright. All rights reserved.

Dual-crosslinked starch−poly(ester urethane)−oligochitosan films with high starch content: Application as biodegradable food packaging

This work offered a dual-crosslinking strategy to prepare starch−poly(ester urethane)−oligochitosan (SPEO) composites with high starch content (> 46 wt%). The crosslinking agent polycaprolactone-based polyurethane prepolymer (PPUP) with terminal −NCO groups and pendant −CHO groups was first synthesized. Then, the starch was modified by PPUP to form a crosslinked structure linked by urethane bonds. Oligochitosan (OCS) was subsequently introduced to produce another crosslinked structure linked by imine bonds, and the films were fabricated by compression molding. The chemical structures and physical performance of SPEO were characterized. Crystallinity, micromorphology and thermal analysis demonstrated that the dual-crosslinking structures enhanced the composite compatibility, which improved their mechanical properties. The surface hydrophilicity, water absorption, and in vitro degradation rate increased slowly with increasing OCS content, while a high crosslinking density provide a good barrier to water vapor permeation and therefore decreased the water vapor permeability (< 128 g/(m2∙24 h)). Due to the residual −NH2 groups of OCS, the composite film of SPEO-6 exhibited certain bacteriostatic activity against E. coli and S. aureus. Furthermore, the cytotoxicity of the composite films was assayed by the MTT method, and relative growth rates were much higher than 75% after incubation for 72 h, indicating high cytocompatibility and non-toxicity to food. The dual-crosslinked high-starch-content composites possessing high security, superior mechanical properties, good biodegradability, low water vapor permeability, and certain bacteriostatic capacity hold great potential to substitute petroleum-derived plastics for fresh-keeping food packaging applications.

Natural sourced and non-toxic hybrid materials for boosting the growth of lettuce in a hydroponic system

Nanostructured hybrid materials, fabricated by combining nanosilica (n-S) obtained from rice husk and oligochitosan (OC) obtained from the shrimp shell, are environmentally friendly substances that can applied in green agriculture. In this study, 50 mg/L of nanostructured hybrid materials were applied on lettuce (Lactuca sativa L. var. longifolia) at different stages of its growth. Most of the hybrid-material-treated lettuce plants showed better growth than that of the control. The most suitable ages for applying the hybrid material to the lettuce are the ages of three weeks (H3W1) and four weeks (H4W1) to stimulate their growth. The longest leaf of the H3W1-treated lettuce increased by 7.14%, its fresh weight by 8.51%, the numbers of leaves by 4.67%, and the content of total chlorophyll by 24.89% compared with those of the control lettuce. The longest leaf of H4W1 increased by 9.52%, its fresh weight by 26.27%, the number of leaves by 9.52%, and the total chlorophyll content by 52.87% compared with those of the control lettuce. Hence, the hybrid material could be used as a green agrochemical with a great potential in modern agriculture. It can help replace and reduce the use of toxic chemical fertilizers and plant-protection products currently used on the market.

Enhancement of surimi gel properties through the synergetic effect of fucoidan and oligochitosan

For the first time, two common marine-derived dietary fibres (MDFs), fucoidan (FU) and oligochitosan (OCS), were introduced as textural and nutritional enhancers in hairtail surimi gels. The MDFs could assist with inhabiting the endogenous proteolytic enzyme activity, unfolding the myosin to expose more reactive domains, inducing favorable protein conformational transition, and thus, promoting gelation. The highly hydrophilic MDFs rich in –OH groups can bind water molecules via strong hydrogen bonds, facilitating water redistribution within the gel network. Driven by the enhanced chemical forces, a stable protein-FU-OCS gel is obtained, which improves the hardness by almost 100% and the water holding capacity from 86.25% to 92.25%. Collectively, this study demonstrates that MDFs are a group of effective additives to improve gel characteristics and nutritional profiles of surimi-based seafood products. The proposed MDF-protein interaction model would guide the application of MDFs as novel additives in the food industry.

Oligochitosan recovered from shrimp shells through subcritical water hydrolysis: Molecular size reduction and biological activities

Oligochitosan (OC) from shrimp shells derived chitosan was prepared using subcritical water hydrolysis (SWH) and their physicochemical and bio-functional properties were observed in this study. Reaction time of SWH was varied from 15 min to 60 min and the temperature from 140 °C to 170 °C. Gel permeation chromatography (GPC) confirmed that the molecular weight of the chitosan hydrolysate (CH) at 170 °C/15 min was obtained at 3.06 kDa. Fourier transform infrared and X-ray diffraction spectroscopy confirmed the conversion of OC from CH. Bio-functionality of CH was tested on the basis of antioxidant, antimicrobial, and anticancer activities. The ability of OC to act against the pancreatic cancer cell line Panc 1 was analyzed by MTT assay and Syto 9/PI fluorescent techniques. The MTT assay indicated that the maximum cytotoxicity was revealed by OC (170 °C/15 min) at 500 µg/mL. This research revealed that SWH can be an efficient method for the production of OC.

Glycosylated cross-linked ovalbumin by transglutaminase in the presence of oligochitosan: Effect of enzyme action time and enhanced functional properties

This study investigated the effects of enzyme action time (1–5 h) on the physicochemical properties, structure, and functionality of transglutaminase-catalyzed ovalbumin (OVA) in the presence of oligochitosan (OCS). Physically combining OVA and OCS led to a substantial increase in particle size and polydispersity index, rendering the mixed system unstable. With the increase of enzyme action time, the particle size of glycosylated and cross-linked OVA (GC-OVA) decreased first and then increased, reaching a minimum value of 411 nm at 4 h. Moreover, the decrease of free amino groups content at 4 h reflected the occurrence degree of glycosylation and cross-linking reaction, which was close to saturation. Diverse methods were used to analyze variations in the molecular structure of OVA, confirming changes in the primary, secondary, and tertiary structures, and the microstructure. The glycosylation grafting and cross-linking with the appropriate extent of the enzymatic action time is the primary reason for improving the foaming, emulsification properties, and DPPH activity of OVA. Moreover, GC-OVA had greater apparent viscosity, G′ and G″ than the other control systems (the untreated OVA and the physical mixture of OVA and OCS) and significantly affected the hardness and cohesion properties in the gel's texture (5.6 and 2.4-fold that of the untreated OVA, respectively). This study provides information for further understanding the effect of glycosylation grafting caused by enzyme cross-linking time on OVA. The study also demonstrates the possibility of obtaining new protein compositions to expand the applications of food proteins.

Complexation of oligochitosan with sodium caseinate in alkalescent and weakly acidic media

Сomplexation of oligochitosan (OCHI) having the degree of acetylation (DA 26 %) with sodium caseinate (SC) at pH 5.8 and 7.2 is described and compared with the complexation of OCHI (DA 2 %) at pH 5.8. In the alkalescent medium, the complexation of OCHI (DA 26 %) is weaker and dualistic depending on SC concentration in the system. In the diluted alkalescent system, the formation of only soluble complexes is observed at OCHI/SC ratio ≤0.9. In the semi diluted one, the complexation results in the formation of insoluble complexes those composition changes symbatically with the OCHI/SC ratio in the system. At pH 5.8, OCHI/SC ratio in insoluble complexes remains the same regardless of OCHI/SC ratio in the solution. At pH 5.8, the electrostatic complexation weakens with an increase in DA and is completely suppressed at a high ionic strength. These results can be promising for construction of biodegradable protein/chitosan drug delivery systems.

Pichia caribbica combined with oligochitosan controlling black spot of tomatoes and the regulation on ROS metabolism of the fruits

Black spot caused by Alternaria alternata is one of the main postharvest diseases of tomato fruits. This research aimed to investigate biocontrol efficacy of Pichia caribbica combined with oligochitosan (OCH) against black spot of tomato fruits and explore the mechanisms involved in improved disease resistance of the fruits by yeast combined with OCH based on analysis of reactive oxygen species (ROS) metabolism. The results indicated that in comparison with P. caribbica alone, yeast combined with OCH (2000 μg/mL) could further reduce black spot of tomato fruits. P. caribbica combined with OCH increased NADPH oxidase (NOX) activity in the fruits compared with the control and the group treated with yeast alone. The activities of enzymatic system for ROS scavenging including antioxidant enzymes, enzymes involved in ascorbate–glutathione (AsA-GSH) and GPX (glutathione peroxidase) cycles, and glutathione S-transferase (GST) in the fruits were induced by yeast combined with OCH. Additionally, the contents of ascorbic acid (AsA) and glutathione (GSH) belonging to non-enzymatic system for ROS scavenging were enhanced in the fruits. Collectively, the induction of NOX and the improvement of enzymatic and non-enzymatic systems for ROS scavenging resulted in the decrease in O2–·, H2O2 and malondialdehyde (MDA) production in the fruits, thus promoting the disease resistance of tomato fruits. This research will provide new ideas for the control of postharvest diseases of tomato fruits.

Osteogenic and anti-inflammatory potential of oligochitosan nanoparticles in treating osteomyelitis

Osteomyelitis is commonly developed via hematogenous spreading or direct inoculation of bacteria from orthopedics trauma. Pathogens-induced bone destruction impedes the penetration of antibiotics to the infection site, and the severe inflammation further compromises the traditional treatment outcome. In this work, vancomycin-loaded oligochitosan nanoparticles (Van-NPs) with antibacterial, antibiofilm, antioxidant as well as bone regenerative properties are prepared using sodium tripolyphosphate (TPP) as a crosslinker, and employed for the treatment of osteomyelitis. Van-NPs exhibit strong interactions with dissociative S. aureus and biofilms due to the positive zeta potential, the additional effect between vancomycin (Van) and oligochitosan (OCS) further contributes to an enhanced antibacterial and antibiofilm outcome. The in vitro osteogenic differentiation of rBMSCs is facilitated by the antioxidant ability of Van-NPs and the TPP-induced activation of ERK1/2 and p38 signaling pathways. Moreover, the combination of Van-NPs with PLGA-PEG-PLGA gel (Gel/Van-NPs) achieves successful localized treatment of osteomyelitis in terms of enhanced bacteria elimination, inflammatory modulation, and accelerated bone regeneration. Therefore, Gel/Van-NPs may serve as a promising biomaterial for the optimal treatment of osteomyelitis.

Preparation and Effect of Selenium Nanoparticles/Oligochitosan on the White Blood Cell Recovery of Mice Exposed to Gamma-Ray Radiation

Owing to their excellent bioavailability, high bioactivity, and low toxicity, selenium nanoparticles (SeNPs) are emerging nanomaterials. In this study, SeNPs with a size of ∼41.8 nm were synthesised by γ-irradiation using oligochitosan (OCS) as the stabiliser. As-synthesized SeNPs/OCS were characterised by UV-Vis spectroscopy, transmission electron microscopy, and energy-dispersive X-ray (EDX) analysis. Results revealed that the as-obtained SeNP/OCS powder exhibits high purity. The SeNP/OCS solution’s stability test results indicated that the SeNP/OCS solution stored at 4°C exhibits good stability for 60 days. The SeNP/OCS solution was unstable at ambient temperature, and SeNP/OCS exhibited agglomeration after about 15 days. SeNP/OCS products recovered the total white blood cells of γ-ray irradiated mice. The SeNP/OCS product, which was synthesised by a green approach, with high purity and efficient recuperation of white blood cells, can be used potentially as a functional supplement to assist cancer radiotherapy patients.

The effect of the nanosilica/oligochitosan hybrid material on the growth of lettuce (Lactuca sativa L. var. longifolia)

A nanostructured hybrid material prepared from eco-friendly natural materials such as nanosilica (nSiO2) extracted from rice husk and oligochitosan (OS) isolated from shrimp shells is material of high promise with special properties to be applied in various fields, especially in agriculture. In this study, hybrid nanosilica material based on oligochitosan (SOS) with a concentration of 50 mg/L as nutrient source was supplied to the lettuce (Lactuca sativa) at different stages of growth. The two-week-old lettuce (H2W2) supplied with the hybrid material had an increase in leaf length by 17.24% and root length by 5.26% in comparison with those of the control lettuce. Additionally, the fresh weight and leaf number of the hybrid-supplied plant were 20.39% heavier and 9.09% higher than those of the control samples, respectively. Moreover, the chlorophyll measurement indicated that the total chlorophyll content of H2W2 was 7.61% higher than that of the control, and the plant growth characteristics also increased by 20.39% compared with the control plant. The SOS hybrid material could be seen as a green agrochemical with a great promise of being applied in the modern agriculture. This kind of renewable material also contributes to replacing and declining the numbers of the type of toxic chemical fertilizers and plant protection products used on the market today.

OLIGO CHITOSAN TEST IN THE INITIAL BULBIL GROWTH OF ILES-ILES (Amorphophallus muelleri Blume)

Oligo chitosan is a supplement that can increase growth, accelerate flowering, and increase productivity in several types of agricultural crops, rice and horticultural commodities. The findings of this study, encourage the authors, to further test the Oligo chitosan on the initial growth of the bulbs of Iles-iles. It is known, that Iles-iles (Amorphophallus muelleri Blume) or "Porang" is one type of tuber whose life cycle is quite long, has a slow-growing bulbil, especially in the dry season. This growth delay is caused in addition to genetic traits, also dry environmental conditions come into effect, so if entering the rainy season at a certain time span will soon show a good appearance of growth. Bulbil as a planting material, in order to grow immediately, it is necessary to strive to accelerate its growth, one of which is to use Oligo chitosan. In the cultivation of iles-iles the use of Oligo chitosan to accelerate bulbil growth has never been done. Technological innovations produced by BATAN, have the opportunity to be used in the development of crop cultivation made from tubers. This study aims to test Oligo chitosan to encourage the realization of early growth of bulbil, through the treatment of immersion time and the concentration of Oligo chitosan which is higher than previous experiments that the authors have done. The experiment was conducted in the rainy season of 2019/2020 in the experimental farm of the UPN "Veteran" Yogyakarta Wedomartani Faculty of Agriculture under a tree stand, using a Split Plot Randomized Completely Block Design (RCBD) with three replications. As the main plot is the soaking time of Oligo chitosan solution, consisting of three kinds, namely 2.5 hours (L1), 5 hours (L2), and 7.5 Hours (L3), and as a sub plot is the concentration of the solution consists of 3 stages, namely (5.0 ‰ (K1), 10 ‰ (K2), and 15 ‰ (K3) and one control (without Oligo chitosan). The data obtained were analyzed by Variance Analysis with 95% confidence level, and for the difference test the Duncan Multiple Range Test (DMRT) was used at the 5% level and the Orthogonal Contrast Test The results showed that soaking Oligo chitosan for 2.5 hours (L1) was sufficient to provide a better initial growth effect for Ilesiles bulbil, with a fairly high concentration of 15 ‰ (K3).Keywords: Oligochitosan, Iles-iles or Porang, bulbil, soaking and concentration

Study on the preparation of selenium nanoparticles by gamma Co-60 method and investigate the stability

Among nanoparticle materials, selenium nanoparticles (SeNPs) have attracted wide spread attention due to their excellent bioavailability, high bioactivity and low toxicity compared to other ionic selenium compounds. SeNPs with size ~ 41.75 nm were synthesized by γ-irradiation method using oligochitosan (OC) as stabilizer. The prepared SeNPs/OC were characterized by UV-Vis spectroscopy and transmission electron microscope (TEM) images. The SeNPs/OC powder was also prepared by spray drying technique and the purity was verified by energy dispersive X-ray (EDX) analysis. The results of EDX showed that SeNPs/OC solution was of high purity. The stability ofSeNPs/OC solution was investigated. The results indicated that SeNPs/OC solution had good stability after 60 days of storage at 4ºC. At ambient temperature, the SeNPs/OC solution was unstable and agglomerated after about 15 days. The SeNPs/OC synthesized by γ-irradiation with the advantages of environmental friendly and mass production process may be potentially promising for applications in medicines, functional food and in other fields as well.