Application of Vibrational Spectroscopic Techniques in the Study of the Natural Polysaccharides and Their Cross-Linking Process

Synthesis and characterization of chitosan for medical applications: A review

Chitosan has gained considerable recognition within the field of medical applications due to its exceptional biocompatibility and diverse range of properties. Nevertheless, prior reviews have primarily focused on its applications, offering limited insights into its source materials. Hence, there arises a compelling need for a comprehensive review that encompasses the entire chitin and chitosan life cycle: from the source of chitin and chitosan, extraction methods, and specific medical applications, to the various techniques employed in evaluating chitosan's properties. This all-encompassing review delves into the critical aspects of chitin and chitosan extraction, with a strong emphasis on the utilization of natural raw materials. It elucidates the various sources of these raw materials, highlighting their abundance and accessibility. Furthermore, a meticulous examination of extraction methods reveals the prevalent use of hydrochloric acid (HCl) in the demineralization process, alongside citric, formic, and phosphoric acids. Based on current review information, these acids constitute a substantial 69.2% of utilization, surpassing other mentioned acids. Of notable importance, the review underscores the essential parameters for medical-grade chitosan. It advocates for a degree of deacetylation (DDA) falling within the range of 85%-95%, minimal protein content <1%, ash content <2%, and moisture content <10%. In conclusion, these crucial factors contribute to the understanding of Chitosan's production for medical applications, paving the way for advancements in biomedical research and development.

Phytochemical Profile and Bioactivity of Bound Polyphenols Released from Rosa roxburghii Fruit Pomace Dietary Fiber by Solid-State Fermentation with Aspergillus niger

This study aimed to investigate the phytochemical profile, bioactivity, and release mechanism of bound polyphenols (BPs) released from Rosa roxburghii fruit pomace insoluble dietary fiber (RPDF) through solid-state fermentation (SSF) with Aspergillus niger. The results indicated that the amount of BPs released from RPDF through SSF was 17.22 mg GAE/g DW, which was significantly higher than that achieved through alkaline hydrolysis extraction (5.33 mg GAE/g DW). The BPs released through SSF exhibited superior antioxidant and α-glucosidase inhibitory activities compared to that released through alkaline hydrolysis. Chemical composition analysis revealed that SSF released several main compounds, including ellagic acid, epigallocatechin, p-hydroxybenzoic acid, quercetin, and 3,4-dihydroxyphenylpropionic acid. Mechanism analysis indicated that the disruption of tight structure, chemical bonds, and hemicellulose was crucial for the release of BPs from RPDF. This study provides valuable information on the potential application of SSF for the efficient release of BPs from RPDF, contributing to the utilization of RPDF as a functional food ingredient.

Influence of cellulose viscosity on the physical, mechanical, and barrier properties of the chitosan-based films

This research paper presents a comprehensive investigation into developing biodegradable films for food packaging applications using chitosan (CN) in conjunction with three distinct types of cellulose (CE), each characterized by varying viscosities. The primary objective was to assess the influence of cellulose viscosity on the physical, mechanical, and barrier properties of the resulting films. The medium-viscosity cellulose imparted numerous advantageous qualities to the biodegradable films. These films exhibited optimal thickness (31 μm), ensuring versatility in food packaging while maintaining favorable mechanical properties, blending strength, and flexibility. Also, medium-viscosity cellulose significantly improved the films' barrier performance, particularly regarding oxygen permeability [1.80 × 10-6 (g.mm.m-2. s-1)]. Furthermore, the medium-viscosity cellulose contributed to superior moisture-related properties, including reduced water vapor permeability [14.80 × 10-9 (g.mm.m-2. s-1. Pa-1)], moisture content (13.22 %), and water solubility (22.87 %), while maintaining an appropriate degree of swelling (41.88 %). Moreover, the study employed advanced analytical techniques, including FTIR, XRD, and TGA, to provide critical insights into the films' chemical, structural, and thermal aspects. This research underscored the importance of the viscosity of film formulation materials as a crucial element in designing and efficiently producing films for food packaging.

Polysaccharides from Radix Peucedani: Extraction, Structural Characterization and Antioxidant Activity

In this study, an ultrasound-assisted green extraction method was applied for the extraction of polysaccharides from Radix Peucedani based on deep eutectic solvents (DESs), and the result showed that a DES system composed of betaine and 1,2-propylene glycol with a molar ratio of 1:2 possessed the optimal extraction efficiency for polysaccharides. Single-factor and Box-Behnken designs were used to determine the optimum extraction conditions for the maximum yields of polysaccharides from Radix Peucedani by using DESs. The maximum yields of polysaccharides attained 11.372% within a DES water content of 19%, an extraction time of 36 min, an extraction temperature of 54 °C, a solid-liquid ratio of 1:30 and an ultrasonic irradiation power of 420 W. The physicochemical properties of polysaccharides were analyzed using ICS and FT-IR, and the structure morphology was observed by SEM. The polysaccharides extracted from Radix Peucedani exhibited general antioxidant activities in vitro including DPPH, Hydroxyl and ABTS+ radical-scavenging activity. The antioxidant mechanism of Radix Peucedani polysaccharides was investigated using network pharmacology and molecular docking methods. The result showed that the high binding activity of glucose and IL1B, galactose and CASP3 was recognized as a potential mechanism for the antioxidant effects of Radix Peucedani polysaccharides.

Physicochemical characterization, antioxidative and immunoregulatory activity of polysaccharides from the flower of Hylocereus undatus (Haw.) Britton et Rose

The flower of Hylocereus undatus (Haw.) Britton et Rose is widely recognized as a kind of medicine-food homologous resource due to its high nutritional value. However, there is a lack of in-depth studies on the purification, structure, antioxidative and immunoregulatory activities of polysaccharides from H. undatus flowers (FHRP). The objective of this study was to investigate the primary structure, antioxidative and immunoregulatory activities of the polysaccharides extracted from Hylocereus undatus flower using water extraction and chromatogram purification. Three polysaccharide fractions named FHRP-1, FHRP-2 and FHRP-3 were obtained. The results showed that FHRP-1, FHRP-2 and FHRP-3 (200-800 μg/mL) treatment for 24 h significantly increased the activities of superoxide dismutase (SOD) and catalase (CAT), and reduced the malondialdehyde (MDA) production in RAW 246.7 cells under H2O2-induced oxidative stress. Additionally, all three fractions exhibited immunoregulatory activities by enhancing the pinocytosis of RAW 264.7 cells and promoting the production of nitric oxide (NO), interleukin 6 (IL-6), and tumor necrosis factor α (TNF-α). Among three polysaccharide fractions, FHRP-3 exhibited the most promising antioxidative and immunoregulatory properties, which was attributed to its higher content of uronic acid, moderate molecular weight, and triple-helix conformation. These findings provide preliminary insights into the primary structural information and biological activities of FHRP.

Gold Nanoparticles-Functionalized Cotton as Promising Flexible and Green Substrate for Impedometric VOC Detection

This work focuses on the possible application of gold nanoparticles on flexible cotton fabric as acetone- and ethanol-sensitive substrates by means of impedance measurements. Specifically, citrate- and polyvinylpyrrolidone (PVP)-functionalized gold nanoparticles (Au NPs) were synthesized using green and well-established procedures and deposited on cotton fabric. A complete structural and morphological characterization was conducted using UV-VIS and Fourier transform infrared (FT-IR) spectroscopy, atomic force microscopy (AFM), and scanning electron microscopy (SEM). A detailed dielectric characterization of the blank substrate revealed interfacial polarization effects related to both Au NPs and their specific surface functionalization. For instance, by entirely coating the cotton fabric (i.e., by creating a more insulating matrix), PVP was found to increase the sample resistance, i.e., to decrease the electrical interconnection of Au NPs with respect to citrate functionalized sample. However, it was observed that citrate functionalization provided a uniform distribution of Au NPs, which reduced their spacing and, therefore, facilitated electron transport. Regarding the detection of volatile organic compounds (VOCs), electrochemical impedance spectroscopy (EIS) measurements showed that hydrogen bonding and the resulting proton migration impedance are instrumental in distinguishing ethanol and acetone. Such findings can pave the way for the development of VOC sensors integrated into personal protective equipment and wearable telemedicine devices. This approach may be crucial for early disease diagnosis based on nanomaterials to attain low-cost/low-end and easy-to-use detectors of breath volatiles as disease markers.