Formation of low molecular weight oligomers from chitin and chitosan stimulated by plasma-assisted processes

Effects of chemically reactive species generated in plasma treatment on the physico-chemical properties and biological activities of polysaccharides: An overview

Plasma technology as an advanced oxidation technology, has gained increasing interest to generate numerous chemically reactive species during the plasma discharge process. Such chemically reactive species can trigger a chain of chemical reactions leading to the degradation of macromolecules including polysaccharides. This review primarily summarizes the generation of various chemically reactive species during plasma treatment and their effects on the physico-chemical properties and biological activities of polysaccharides. During plasma treatment, the type of chemically reactive species that play a major role is related to equipment, working gases and types of polysaccharides. The primary chain structure of polysaccharides did not changed much during the plasma treatment, other physico-chemical properties might be changed, such as molecular weight, solubility, hydrophilicity, rheological properties, gel properties, crystallinity, elemental composition, glycosidic bonding, and surface morphology. Additionally, the biological activities of plasma-treated polysaccharides including antibacterial, antioxidant, immunological, antidiabetic activities, and seed germination promotion activities in agriculture could be improved. Therefore, plasma treatment has the potential application in preparing polysaccharides with enhanced biological activities.

Ultrasonic-assisted extraction, analysis and properties of purple mangosteen scarfskin polysaccharide and its acetylated derivative

Purple mangosteen scarfskin polysaccharide has many important physiological functions, but its preparation method, structure, and function need further exploration. A polysaccharide was obtained from mangosteen scarfskin by ultrasonic-assisted extraction and purified. On this basis, its structure and physicochemical properties were investigated. The Congo red experiment was used to determine whether it has a triple helix conformation. The structure of purple mangosteen scarfskin polysaccharide was further analyzed by infrared spectroscopy and nuclear magnetic analysis. The antioxidant activities of the above three polysaccharides were studied by related experiments. It was found that the monosaccharide composition of purple mangosteen scarfskin polysaccharide mainly contained a large amount of arabinose, a small amount of rhamnoose and a very small amount of galacturonic acid, and its core main chain was composed of 1,4-α-arabinose. It did not have this spatial configuration. After the acetylation of purple mangosteen scarfskin polysaccharide, the acetylated derivative with a degree of substitution of 0.33 was obtained. It was found that they had certain scavenging and inhibiting effects on hydroxyl radicals and lipid peroxidation, and their activities were related to the concentration of polysaccharides. Meanwhile, the antioxidant activity of the polysaccharide was significantly enhanced after the modified treatment of acetylation, which indicated that chemical modification could effectively improve some activities of polysaccharide. The above studies provided some reference value for the further research and development of purple mangosteen scarfskin polysaccharide.

Plasma-activated water improves the accessibility of chitinase to chitin by decreasing molecular weight and breaking crystal structure

Chitooligosaccharides, the hydrolysis products of chitin, have superior biological activities and application value to those of chitin itself; however, the ordered and highly crystalline structure of chitin renders its degradation by chitinase difficult. Herein, the effects of plasma-activated water (PAW) pre-treatment on the physicochemical properties, crystal structure, and enzymatic hydrolysis of chitin were investigated. The hydrolysis of PAW-pre-treated chitin (PAW activation time of 5 min) using chitinase from Vibrio harveyi (VhChit2) yielded 71 % more reducing sugar, compared with that from untreated chitin, with the degree of chitin hydrolysis increasing from 13 % without pre-treatment to 23 % post-treatment. Moreover, the amount of VhChit2 adsorbed by chitin increased from 41.7 to 58.2 mg/g. Fourier transform infrared spectrometry revealed that PAW could break the β-1,4-glycosidic bonds of chitin (but had no effects on the hydrogen and amido bonds), thereby decreasing the molecular weight and crystallinity of the polysaccharide, which caused its structural damage and enhanced its enzymatic hydrolysis by chitinase. Consequently, PAW pre-treatment can be considered a simple, effective, and environmentally-friendly method for the biotransformation of chitin as its easier hydrolysis yields high-value products.

Effect of in vitro digestion and fermentation of kiwifruit pomace polysaccharides on structural characteristics and human gut microbiota

Kiwifruit pomace is abundant in polysaccharides that exhibit diverse biological activities and prebiotic potential. This study delves into the digestive behavior and fermentation characteristics of kiwifruit pomace polysaccharides (KFP) through an in vitro simulated saliva-gastrointestinal digestion and fecal fermentation. The results reveal that following simulated digestion of KFP, its molecular weight reduced by 4.7%, and the reducing sugar (CR) increased by 9.5%. However, the monosaccharide composition and Fourier transform infrared spectroscopy characteristics showed no significant changes, suggesting that KFP remained undigested. Furthermore, even after saliva-gastrointestinal digestion, KFP retained in vitro hypolipidemic and hypoglycemic activities. Subsequently, fecal fermentation significantly altered the physicochemical properties of indigestible KFP (KFPI), particularly leading to an 89.71% reduction in CR. This indicates that gut microbiota could decompose KFPI and metabolize it into SCFAs. Moreover, after 48 h of KFPI fecal fermentation, it was observed that KFPI contributed to maintaining the balance of gut microbiota by promoting the proliferation of beneficial bacteria like Bacteroides, Lactobacillus, and Bifidobacterium, while inhibiting the unfavorable bacteria like Bilophila. In summary, this study offers a comprehensive exploration of in vitro digestion and fecal fermentation characteristics of KFP, providing valuable insights for potential development of KFP as a prebiotic for promoting intestinal health.

Preparation of water-soluble chitosan oligosaccharides by oxidative hydrolysis of chitosan powder with hydrogen peroxide

Chitosan (CS) is only soluble in weak acid medium, thereby limiting its wide utilisation in the field of biomedicine, food, and agriculture. In this report, we present a method for preparing water-soluble CS oligosaccharides (COSs) at high concentration (∼10%, w/v) via the oxidative hydrolysis of CS powder with molecular weight (Mw) ∼90,000 g/mol) in 2% H2O2 solution at ambient temperature by a two-step process, namely, the heterogeneous hydrolysis step and homogeneous hydrolysis step. The resultant COSs were characterised by gel permeation chromatography (GPC), fourier transforms infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV-Vis), proton nuclear magnetic resonance spectroscopy (1H NMR) and X-ray diffraction (XRD) spectroscopy. The resulting products were composed of COSs (Mw of 2000-6600 g/mol) that were completely soluble in water. The results also indicated that the structure of COSs was almost unchanged compared with the original CS unless Mw was low. Accordingly, COSs with low Mw (∼2000 g/mol) and high concentration (10%, w/v) could be effectively prepared by the oxidative hydrolysis of CS powder using hydrogen peroxide under ambient conditions.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2017-2018

This review is the tenth update of the original article published in 1999 on the application of matrix-assisted laser desorption/ionization mass spectrometry (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2018. Also included are papers that describe methods appropriate to glycan and glycoprotein analysis by MALDI, such as sample preparation techniques, even though the ionization method is not MALDI. Topics covered in the first part of the review include general aspects such as theory of the MALDI process, new methods, matrices, derivatization, MALDI imaging, fragmentation and the use of arrays. The second part of the review is devoted to applications to various structural types such as oligo- and poly-saccharides, glycoproteins, glycolipids, glycosides, and biopharmaceuticals. Most of the applications are presented in tabular form. The third part of the review covers medical and industrial applications of the technique, studies of enzyme reactions, and applications to chemical synthesis. The reported work shows increasing use of combined new techniques such as ion mobility and highlights the impact that MALDI imaging is having across a range of diciplines. MALDI is still an ideal technique for carbohydrate analysis and advancements in the technique and the range of applications continue steady progress.

Antifungal Agent Chitooligosaccharides Derived from Solid-State Fermentation of Shrimp Shell Waste by Pseudonocardia antitumoralis 18D36-A1

Shrimp shell waste is a potential source of the biopolymer chitin. Through fermentation, chitin can be converted into its derivative products. This study aimed to isolate and characterize the products of the biodegradation of chitin from shrimp shell waste through a solid-state fermentation process using actinomycetes. Actinomycete isolates were obtained from tunicate marine biota collected from the waters of Buleleng, Bali, using a dilution technique on 1% chitin colloid agar medium. The isolated actinomycetes were cultivated on a shrimp shell waste medium for 7 days, and then the products of the biodegradation of the oligomers were extracted using water. The extracts of the biodegradation products of the shrimp shells were isolated through several chromatographic steps and analyzed using LC–MS–MS, and the bioactivity of the biodegradation products against fungi was tested. The morphological observations and phylogenetic analysis showed that the isolate 18D36-A1 was a rare actinomycete with the proposed name Pseudonocardia antitumoralis 18D36-A1. The results of the analysis using TLC showed that the solid-state fermented water isolate 18D36-A1 produced several oligomeric components. These results indicate that the isolate 18D36-A1 was able to convert chitin into chitooligosaccharides. Further isolation of the extract produced the active fraction D36A1C38, which can inhibit the growth of fungi by 74% at a concentration of 1 mg/mL. This initial information is very important for further studies related to the development of a solid-state fermentation process for obtaining bioactive compounds from shrimp shell waste.

Extraction, isolation, structural characterization, and antioxidant activity of polysaccharides from elderberry fruit

The isolation, purification, and antioxidant activity of polysaccharides extracted from elderberry fruits were studied. Two neutral polysaccharides (EFP-0 and EFP-1) and three acidic polysaccharides (EFP-2, EFP-3, and EFP-4) were isolated from elderberry. EFP-0, EFP-1, EFP-2, EFP-3, and EFP-4 all contain arabinose, galactose, glucose, and mannose, with molecular weights of 1.7981 × 10⁶, 7.0523 × 10⁶, 7.7638 × 10⁶, 4.3855 × 10⁵, and 7.3173 × 10⁵ Da, respectively. Structural characterization showed that the backbone of EFP-2 consisted of →4)-Manp (1→4)-β-D-Glcp (1→ and →4)-β-D-Glcp (1→5)-α-L-Araf (1→units, and T-α-L-Araf (1→ and T-β-D-Galp (1→ residues were detected by methylation analysis and NMR analysis. In addition, the MTT assay and zebrafish oxidative damage assay showed that EFP-2 had a protective effect on H₂O₂-damaged RAW264.7 cells in a dose-dependent manner, and zebrafish with the addition of EFP-2 would have low levels of ROS in vivo which showed significant antioxidant activity. Therefore, the results showed that the elderberry polysaccharides have antioxidant activity and can be used as potential antioxidants in functional foods.

Ionic liquid-assisted synthesis of chitin-ethylene glycol hydrogels as electrolyte membranes for sustainable electrochemical capacitors

A novel chitin–ethylene glycol hybrid gel was prepared as a hydrogel electrolyte for electrical double-layer capacitors (EDLCs) using 1-butyl-3-methylimidazolium acetate [Bmim][Ac] as a chitin solvent. Examination of the morphology and topography of the chitin–EG membrane showed a homogeneous and smooth surface, while the thickness of the membrane obtained was 27 µm. The electrochemical performance of the chitin–EG hydrogel electrolyte was investigated by cyclic voltammetry and galvanostatic charge/discharge measurements. The specific capacitance value of the EDLC with chitin–EG hydrogel electrolyte was found to be 109 F g⁻¹ in a potential range from 0 to 0.8 V. The tested hydrogel material was electrochemically stable and did not decompose even after 10,000 GCD cycles. Additionally, the EDLC test cell with chitin–EG hydrogel as electrolyte exhibited superior capacitance retention after 10,000 charge/discharge cycles compared with a commercial glass fiber membrane.

Purification, Structural Characterization, and Anti-Inflammatory Effects of a Novel Polysaccharide Isolated from Orostachys fimbriata

The present study elucidated the structural characteristics and anti-inflammatory activity of a novel polysaccharide isolated from Orostachys fimbriata, which is a traditional Chinese medicinal plant. O. fimbriata polysaccharide (OFP) was extracted and subsequently purified by chromatography using a DEAE cellulose-52 and Sephadex G-75 column. The molecular weight was determined as 6.2 kDa. HPGPC and monosaccharide composition analysis revealed a homogeneous polysaccharide containing only Glc. Chromatography and spectral analysis showed that the possible chemical structure consisted of →4)-α-Glcp-(1→ and a small quantity of →4,6)-β-Glcp-(1→ in the main chain and →6)-β-Glcp-(1→, α-Glcp-(1→, and β-Glcp-(1→ in the side chain. Morphological analysis using scanning electron microscopy (SEM) and atomic force microscopy (AFM) indicated that OFP had a multi-branched structure, and the sugar chain molecules of polysaccharide appeared aggregated. OFP was found to exhibit anti-inflammatory activity by reducing the secretion of inflammatory factors in RAW264.7 cells and by decreasing the extent of xylene-induced ear swelling in mice.

Advances in chitooligosaccharides chemical modifications

Chitooligosaccharides (COS) differ from chitosan by their molar mass: those of COS are defined to be lower than 20 kg mol^-1 . Their functionalization is widely described in the literature and leads to the introduction of new properties that broaden their application fields. Like chitosan, COS modification sites are mainly primary amine and hydroxyl groups. Among their chemical modification, one can find amidation or esterification, epoxy-amine/hydroxyl coupling, Schiff base formation, and Michael addition. When depolymerized through nitrous deamination, COS bear an aldehyde at the chain end that can open the way to other chemical reactions and lead to the synthesis of new interesting amphiphilic structures. This article details the recent developments in COS functionalization, primarily focusing on amine and hydroxyl groups and aldehyde-chain end reactions, as well as paying considerable attention to other types of modification. We also describe and compare the different functionalization protocols found in the literature while highlighting potential mistakes made in the chemical structures accompanied with suggestions. Such chemical modification can lead to new materials that are generally nontoxic, biobased, biodegradable, and usable in various applications.

Structural characterization and antioxidant activities of one neutral polysaccharide and three acid polysaccharides from Ziziphus jujuba cv. Hamidazao: A comparison

A neutral polysaccharide (HJP-1a) and three acid polysaccharides (HJP-2, HJP-3 and HJP-4) were obtained from Z. jujuba cv. Hamidazao. HJP-1a was mainly composed of arabinose and galactose in a ratio of 56.9:20.0, with an average molecular weight of 3.115 × 10⁴ g/mol. HJP-2, HJP-3 and HJP-4 were homogeneous heteropolysaccharides mainly containing galacturonic acid, arabinose and galactose, with average molecular weights of 4.590 × 10⁴, 6.986 × 10⁴ and 1.951 × 10⁵ g/mol, respectively. Structural characterization indicated that the backbone of HJP-3 appeared to be mainly composed of →4)-α-d-GalpA (1→ and →2,4)-α-l-Rhap (1→ residues with some branches consisting of →5)-α-l-Araf (1→ residues and terminals of T-α-l-Araf (1→ and T-β-d-Galp residues. The four purified fractions displayed dose-dependent radical scavenging activity on ABTS⁺ radicals and reducing capacity, as well as excellent protective effect on H₂O₂-induced HepG2 cells and metronidazole-damaged zebrafish embryos, especially HJP-2 in vitro and HJP-1a in vivo. Therefore, the polysaccharides from Z. jujuba cv. Hamidazao could be used as a potential antioxidant in functional foods.

Characterization of Different Salt Forms of Chitooligosaccharides and Their Effects on Nitric Oxide Secretion by Macrophages

In this paper, chitooligosaccharides in different salt forms, such as chitooligosaccharide lactate, citrate, adipate, etc., were prepared by the microwave method. They were characterized by SEM, FTIR, NMR, etc., and the nitric oxide (NO) expression was determined in RAW 264.7 cells. The results showed that pure chitooligosaccharide was an irregular spherical shape with rough surface, and its different salt type products are amorphous solid with different honeycomb sizes. In addition to the characteristic absorption peaks of chitooligosaccharides, in FTIR, the characteristic absorption of carboxyl group, methylene group, and aromatic group in corresponding acid appeared. The characteristic absorption peaks of carbon in carboxyl group, hydrogen and carbon in methyl, methylene group, and aromatic group in corresponding acid also appeared in NMR. Therefore, the sugar ring structure and linking mode of chitooligosaccharides did not change after salt formation of chitooligosaccharides. Different salt chitooligosaccharides are completely different in promoting NO secretion by macrophages, and pure chitooligosaccharides are the best.

Chitosan Plasma Chemical Processing in Beam-Plasma Reactors as a Way of Environmentally Friendly Phytostimulants Production

A novel technique of phytoactive water-soluble chitooligosaccharide (COS) production in low-temperature plasma is described. Design, operation, and control of plasma chemical reactors used to produce COS from the powder of high molecular weight chitosan are presented. The electron beam plasma is strongly non-equilibrium and chemically active; plasma was excited by injecting the scanning electron beam into reaction volume filled with aerosol, containing oxygen and chitosan powder. Plasma chemical processes, responsible for the raw chitosan destruction and techniques of these processes to obtain control of products of optimal molecular weight, are considered. COS, in amounts sufficient for laboratory tests with some plants, were produced. Tests showed that the addition of COS into the liquid growing medium at 0.25 and 1 mg/mL stimulates root growth in Arabidopsis thaliana seedlings (Col-0) by up to 40%, with respect to control plants. Foliar application of these COS formulations at 0.25 mg/mL on tomato plants (cv. Micro-Tom) also resulted in increases between 11.9% and 36% in two important plant productivity indicators (flower and fruit numbers) compared to the control plants. Being environmentally friendly (and resource saving) the electron beam plasma technology of renewable natural biopolymer processing can be considered as a competitive way to produce biostimulants for commercial agriculture.