Here, we describe and assess a method for reusing specific food waste to make hydrogels, which can be employed to improve the efficacy of agrochemicals and water. It represents an approach for tackling current challenges, such as food waste, water management, and pesticide optimization. Depending on the formulation, the hydrogels were created by crosslinking pectin and starch with CaCl₂ or sodium trimetaphosphate. FTIR and SEM were employed to investigate the methylation degree of the extracted pectin, as well as the surface morphology and interior structure of the hydrogels. The swelling behavior and water retention in sandy soil have been investigated. In addition to the hydrogels’ potential to control and reduce pesticide loss, the herbicide Picloram is a model compound. The results show that the hydrogels have important swelling, up to 300%, and a capacity to retain water, preserve, and increase the water content in sandy soil up to 12 days. Picloram experiments show that hydrogels can limit herbicide mobility for up to 30 days under controlled conditions. The conversion of food wastes to highly valuable materials is a promising approach to optimize the water consumption and the loss of agrochemicals regarding sustainable agriculture.

Исследование влияния способа получения комплексов включения грамицидина С и β-циклодекстрина на их технологические показатели

Low biodegradability of several dyes leads to their accumulation in water, causing ecological and health damage. The adsorption and, in particular, biosorption processes are widely applied for the wastewater treatment. This article presents the first comparative study of the Allura red dye removal under neutral pH at 25 oC applying novel biosorbents: carboxyethyl chitosan hydrogel (CEC) and cryogel of carboxyethyl chitosan cross-linked with butanediol-1,4 diglycidyl ether (DEB-CEC). The gels were synthesized in “green” manner, and the characterization revealed porous structure and high swelling for both biopolymer compositions, which are the properties important for adsorption. The kinetic studies demonstrated that the adsorption rate for DEB-CEC is better represented by pseudo-second-order, while CEC followed better pseudo-first-order kinetics. The adsorption isotherm of Allura Red suited the Temkin model for both samples, with the maximum adsorption capacity of 22.523 mg/g (45.4 μmol/g) and 10.482 mg/g (21.1 μmol/g) for CEC and DEB-CEC, respectively. The results demonstrated that CEC and DEB-CEC polymers can be used as biodegradable and eco-friendly biosorbents for Allura Red dye removal from aqueous solutions, making these biosorbents promising for wastewater treatment and prevention of the azo-dye environmental pollution.

A growing number of alternative agro-industrial waste sources are being considered as possible sources of pectin because of the growing market demand. Pectin's multifunctionality stems from the nature of its molecule, which varies in its chemical structures, physicochemical characteristics, and possible uses based on the extraction methods and sources used. Green methods utilizing microwaves and ultrasound are becoming more popular, in addition to the traditional extraction of pectin, which relies on the use of acids and/or chelators. As a result, this review focuses on patents related to the extraction of pectin from food and food waste using ultrasound assisted technologies. The following patent databases were searched using International Patent Classification (IPC) codes and relevant keywords: PatFT-AppFT, Espace Patent Search, Information Retrieval System, Eurasian Patent Office Search, and Patentscope. Based on the analysis findings, which cover the years 2003 to 2023, 54 pertinent documents—the majority of which were issued in China—were chosen and categorized into multiple groups based on their objectives, methods for extraction intensification, and raw materials. According to the data, 2017 had the greatest number of patent registrations in the industry.

The applicability of native chitosan-based compositions is constrained by their limited solubility in weakly alkaline and neutral media, a consequence of inherent structural features. To overcome this limitation, carboxyalkylation strategies such as the gel-phase Michael synthesis of N-carboxyethylchitosan (N-CEC) were investigated with a focus on optimizing reaction parameters to enhance yield and tailor biopolymer properties. Structural confirmation of the synthesized polymers was performed via FT-IR and SEM, while elemental analysis quantified the degree of substitution (DS), which correlated with temperature in the following way: DS = 0.96–1.10 at 50 °C, 1.07–1.12 at 60 °C and 1.16–1.32 at 70 °C. Porosity measurements indicated pore sizes ranging from 50 to 200 µm in all samples; however, total porosity varied significantly, reaching a maximum of 15 % at 70 °C and decreasing to 4–10 % at lower temperatures. N-CEC exhibited pH‑dependent swelling, with minimal expansion (100–150 %) at low pH and a 2–3-fold increase at pH > 7, which was attributed to COO⁻ group formation. These findings position N-CEC as a promising material for pH-responsive applications.

Sulfoethyl chitosan (SEC) is an anionic chitosan derivative obtained through N‑, O‑, or mixed O, N‑substitution with sulfoethyl groups, which significantly enhances water solubility across a wide pH range, imparts strong polyelectrolyte character, and confers heparin‑mimicking biological properties. This review provides a comprehensive overview of SEC synthesis approaches, chemoselective routes thereof, and the influence of the degree of substitution (DS) and substitution pattern on solubility, swelling, thermal stability, and metal‑ion sorption selectivity. Characterization techniques including ¹H NMR, elemental analysis, FT‑IR, X-ray diffraction and molecular weight determination approaches are discussed with their specific challenges for polyelectrolyte derivatives, including sample purity and aggregation. The impact of sulfoethylation on biological properties including anticoagulant activity, hemocompatibility, cytotoxicity, antimicrobial effect, DNA protective activity was evaluated for sulfoethylated chitosan and its precursors, chitin and chitin‑glucan complex, revealing distinct structure-activity trends governed by the degree of acetylation and substitution pattern. Representative applications include selective solid‑phase extraction of copper from environmental waters, anticoagulant coatings, and macroporous cryogels for long‑term bacterial stabilization at ambient temperatures over 12 months. Despite its versatility, SEC remains under‑patented compared to other chitosan derivatives. Critical knowledge gaps persist, including the absence of systematic DS-bioactivity and regioselectivity-bioactivity relationships and long‑term stability studies, which raises doubts on the industrial demand of the biopolymer. Future perspectives emphasize standardized protocols for characterization and for biological activity assessment, pilot manufacturing with reduced toxic and environmental impact, and interdisciplinary efforts to develop advanced functional materials. With focused attention on these priorities, SEC has potential to transition from a laboratory derivative to a commercially viable biopolymer.