Design of renewable poly(amidoamine)/hemicellulose hydrogels for heavy metal adsorption

Synthesis of xylan and lignin based hydrogels and their use as growth media for rice (Oryza sativa)

Different hydrogels were synthesised using lignin and xylan (extracted from rice straw) as the raw material, PVA as matrix template, citric acid, and succinic acid as crosslinkers and were structurally characterised by FT-IR and SEM analysis. Citric acid cross-linked hydrogels caused loose bonding between polymers and resulted in formation of large pores whereas succinic acid cross-linked hydrogels were observed to have less porosity and tight bonding network. The swelling ratio and reswelling capacity of hydrogels revealed that lignin hydrogels outperformed all other hydrogels. All the synthesised hydrogels were tested for their use as soil culture media ingredient for the germination of rice seedlings. All the hydrogels performed well in stress conditions as compared to normal conditions. Xylan/lignin hydrogel and lignin hydrogels performed best under stress conditions. These hydrogels could be used effectively as an ingredient of soil culture media owing to their tendency to absorb and retain water properly.

Plant Polysaccharides in Engineered Pharmaceutical Gels

Hydrogels are a great ally in the pharmaceutical and biomedical areas. They have a three-dimensional polymeric structure that allows the swelling of aqueous fluids, acting as an absorbent, or encapsulating bioactive agents for controlled drug release. Interestingly, plants are a source of biogels, specifically polysaccharides, composed of sugar monomers. The crosslinking of these polymeric chains forms an architecture similar to the extracellular matrix, enhancing the biocompatibility of such materials. Moreover, the rich hydroxyl monomers promote a hydrophilic behavior for these plant-derived polysaccharide gels, enabling their biodegradability and antimicrobial effects. From an economic point of view, such biogels help the circular economy, as a green material can be obtained with a low cost of production. As regards the bio aspect, it is astonishingly attractive since the raw materials (polysaccharides from plants-cellulose, hemicelluloses, lignin, inulin, pectin, starch, guar, and cashew gums, etc.) might be produced sustainably. Such properties make viable the applications of these biogels in contact with the human body, especially incorporating drugs for controlled release. In this context, this review describes some sources of plant-derived polysaccharide gels, their biological function, main methods for extraction, remarkable applications, and properties in the health field.

Changes of High-Purity Insoluble Fiber from Soybean Dregs (Okara) after Being Fermented by Colonic Flora and Its Adsorption Capacity

In order to explore the changes and properties of high-purity insoluble dietary fiber from okara (HPIDF) after entering the colon and be fermented by colonic flora, fermented high-purity insoluble dietary fiber (F-HPIDF) was obtained by simulated fermentation in vitro by HPIDF and colonic flora from C57BL/6 mice. For exploring the differences of HPIDF and F-HPIDF, the changes of structure (SEM. FTIR, XRD, particle size, specific surface area, monosaccharide composition) and adsorption properties (water, oil, heavy metal irons, harmful substances) of HPIDF/F-HPIDF were explored. The results showed that F-HPIDF had a higher water-holding capacity (19.17 g/g), water-swelling capacity (24.83 mL/g), heavy metals-adsorption capacity (Cd²⁺: 1.82 μmol/g; Pb²⁺: 1.91 μmol/g; Zn²⁺: 1.30 μmol/g; Cu²⁺: 0.68 μmol/g), and harmful substances-adsorption capacity (GAC: 0.23 g/g; CAC: 14.80 mg/g; SCAC: 0.49 g/g) than HPIDF due to the changes of structure caused by fermentation. In addition, with the fermentation of HPIDF, some beneficial substances were produced, which might be potential intestinal prebiotics. The study of F-HPIDF strengthens the speculation that HPIDF may have potential bioactivities after entering the colon, which proved that okara-HPIDF may have potential functionality.