Effects of degree of substitution and irradiation doses on the properties of hydrogel prepared from carboxymethyl-sago starch and polyethylene glycol

Green, tough, and heat-resistant: A GDL-induced strategy for starch-alginate hydrogels

Hydrogels fabricated by non-covalent interaction garnered significant attention for their eco-friendly and robust mechanical attributes, and are often used in food, medicine and other fields. Although starch-alginate hydrogels exhibit high adhesion and are environmentally sustainable, their applications are limited due to their low elasticity and hardness. Addressing this challenge, we introduce a solvent-induced strategy using glucolactone (GDL) to fabricate hydrogels with enhanced strength and thermal resilience. Utilizing corn starch with varying amylose contents, sodium alginate and calcium carbonate to prepare a double network structure. This GDL-induced hydrogel outperforms most previous starch-based hydrogels in mechanical robustness and thermal stability. Typical starch-alginate hydrogel had a homogeneous network structure and exhibited a high tensile stress of 407.57 KPa, and a high enthalpy value of 1857.67 J/g. This investigation furnishes a facile yet effective method for the synthesis of hydrogels with superior mechanical and thermal properties, thereby broadening the design landscape for starch-based hydrogels.

Effect of polyethylene glycol on polysaccharides: From molecular modification, composite matrixes, synergetic properties to embeddable application in food fields

Polyethylene glycol (PEG) is a flexible, water-soluble, non-immunogenic, as well as biocompatible polymer, and it could synergize with polysaccharides for food applications. The molecular modification strategies, including covalent bond interactions (amino groups, carboxyl groups, aldehyde groups, tosylate groups, etc.), and non-covalent bond interactions (hydrogen bonding, electrostatic interactions, etc.) on PEG molecular chains are discussed. Its versatile structure, group modifiability, and amphiphilic block buildability could improve the functions of polysaccharides (e.g., chitosan, cellulose, starch, alginate, etc.) and adjust the properties of combined PEG/polysaccharides with outstanding chain tunability and matrix processability owing to plasticizing effects, compatibilizing effects, steric stabilizing effects and excluded volume effects by PEG, for achieving the diverse performance targets. The synergetic properties of PEG/polysaccharides with remarkable architecture were summarized, including mechanical properties, antibacterial activity, antioxidant performance, self-healing properties, carrier and delivery characteristics. The PEG/polysaccharides with excellent combined properties and embeddable merits illustrate potential applications including food packaging, food intelligent indication/detection, food 3D printing and nutraceutical food absorption. Additionally, prospects (like food innovation and preferable nutrient utilization) and key challenges (like structure-effectiveness-applicability relationship) for PEG/polysaccharides are proposed and addressed for food fields.

Innovations in hydrogel-based manufacturing: A comprehensive review of direct ink writing technique for biomedical applications

Direct ink writing (DIW) stands as a pioneering additive manufacturing technique that holds transformative potential in the field of hydrogel fabrication. This innovative approach allows for the precise deposition of hydrogel inks layer by layer, creating complex three-dimensional structures with tailored shapes, sizes, and functionalities. By harnessing the versatility of hydrogels, DIW opens up possibilities for applications spanning from tissue engineering to soft robotics and wearable devices. This comprehensive review investigates DIW as applied to hydrogels and its multifaceted applications. The paper introduces a diverse range of printing techniques while providing a thorough exploration of DIW for hydrogel-based printing. The investigation aims to explain the progress made, challenges faced, and potential trajectories that lie ahead for DIW in hydrogel-based manufacturing. The fundamental principles underlying DIW are carefully examined, specifically focusing on rheological attributes and printing parameters, prompting a comprehensive survey of the wide variety of hydrogel materials. These encompass both natural and synthetic variations, all of which can be effectively harnessed for this purpose. Furthermore, the review explores the latest applications of DIW for hydrogels in biomedical areas, with a primary focus on tissue engineering, wound dressing, and drug delivery systems. The document not only consolidates the existing state of DIW within the context of hydrogel-based manufacturing but also charts potential avenues for further research and innovative breakthroughs.

Preparation and characterization of particle-filled microgels by chemical cross-linking based on zein and carboxymethyl starch for delivering the quercetin

This work aimed to develop novel particle-filled microgels based on zein and carboxymethyl starch for delivering quercetin (Que). The anti-solvent precipitation and chemical cross-linking methods were combined to produce the zein-carboxymethyl starch particle-filled microgels (SM-Z). The critical finding of the study was that adding zein nanoparticles significantly improved the strength, water holding capacity, and thermal stability of carboxymethyl starch microgel (SM). Besides, SM-Z had good biodegradability, and the particle size was about 44-61 μm. SM-Z successfully encapsulated Que with a high encapsulation efficiency of 86.7 %. Que-loaded SM-Z (Q/SM-Z) significantly enhanced 30 d storage and UV light stability (up to 89.4 % retention rate) of Que than the Que-loaded SM (Q/SM). Q/SM-Z exhibited pH-responsive swelling behavior, and the swelling was greatest in the simulated intestinal fluid (pH = 7). Besides, the Q/SM-Z showed good stability in simulated gastric fluids and sustained release of Que in simulated intestinal fluids, 72.5 % Que was released at 8 h. During Que transport in Caco-2 cell monolayers, Q/SM (5.8 %) and Q/SM-Z (9.7 %) were significantly higher than free Que (1.93 %). Therefore, as an oral delivery system for hydrophobic active substances, SM-Z possesses good biodegradability and pH-responsive intestinal-targeted delivery capability, providing a new strategy for designing starch-based encapsulation materials.

Electron beam irradiation-assisted prepare pea starch nanocrystals and characterization of their molecular structure, physicochemical and rheological properties

Electron beam irradiation (EBI) is an environmentally friendly physical modification technology. In this study, pea starch nanocrystals (SNC) were prepared by EBI-assisted pretreatment, and investigated the effects of EBI on the multiscale structure and physicochemical properties of SNC. EBI-assisted pretreatment didn't change the particle morphology, crystalline type and FT-IR spectra of SNC. However, EBI-SNC's relative crystallinity and short-range orderliness index (R1047/1022) significantly increased with increasing irradiation dose (5 KGy-20 KGy). In addition, EBI-assisted pretreatment caused the long chains of SNC's amylopectin to break into short chains. Moreover, EBI-assisted treatment significantly reduced the mean size, molecular weight, apparent amylose content, swelling power and SDS + RS content of SNC, while increasing the solubility, zeta potential and RDS content. Furthermore, the flow properties of the EBI-SNC samples were increased. The results show that EBI effectively changed the structural and functional properties of SNC, and the excellent functional properties are expected to broaden the application range of SNC.

Enhancement of the carboxymethylation of corn starch via induced electric field

This study aimed to enhance the synthesis of carboxymethyl starch (CMS) by induced electric field (IEF). Corn starch was alkalized, pumped into IEF system, and then reacted with monochloroacetic acid at excitation voltages of 0-400 V. IEF enhanced the carboxymethylation by accelerating the rate of OH- and ClCH2COO- attacking starch particles and slightly intensifying the thermal effect by ~7.1 °C (30 min). Compared with the control (0 V), IEF increased the degree of substitution and reaction efficiency by 0.056-0.148 and 9.37-24.56 %, caused more destruction in starch granular and crystal structure, and thus increased its water solubility, swelling power, and paste transparency. Furthermore, some new crystals were formed during IEF treatment, which enhanced the thermostability of CMS, showing an increase of the maximum decomposition temperature by 16-26 °C. Overall, the results classified that IEF could improve the carboxymethylation and enhance the thermostability of products, which provided guides for the applications of electro-techniques in starch modification involving charged species.

Ionizing and nonionizing radiations can change physicochemical, technofunctional, and nutritional attributes of starch

Challenges for the food/non-food applications of starch mostly arise from its low stability against severe processing conditions (i.e. elevated temperatures, pH variations, intense shear forces), inordinate retrogradability, as well as restricted applicability. These drawbacks have been addressed through the modification of starch. The escalating awareness of individuals toward the presumptive side effects of chemical modification approaches has engrossed the attention of scientists to the development of physical modification procedures. In this regard, starch treatment via ionizing (i.e. gamma, electron beam, and X-rays) and non-ionizing (microwave, radiofrequency, infrared, ultraviolet) radiations has been introduced as a potent physical strategy offering new outstanding attributes to the modified product. Ionizing radiations, through dose-dependent pathways, are able to provoke depolymerization or cross-linking/grafting reactions to the starch medium. While non-ionizing radiations could modify the starch attributes by changing the morphology/architecture of granules and inducing reorientation/rearrangement in the molecular order of starch amorphous/crystalline fractions.

Development of eco-friendly antifungal and antibacterial adhesive derived from modified cassava starch waste/polyvinyl alcohol containing green synthesized nano-silver

Environmentally friendly biopolymer-based wood adhesives are an inevitable trend of wood product development to replace the use of harmful formaldehyde-based adhesives. In this research, a new eco-friendly modified cassava starch waste-based adhesive via carboxymethylation (CMS), and blending with polyvinyl alcohol (PVA), tannic acid (TA) and green synthesized silver nanoparticles (AgNPs) was prepared. The effects of TA content on green synthesis of AgNPs (Ag-TA) and bio-adhesive nanocomposite properties were investigated. The use of 5 wt% TA for AgNPs synthesis (Ag-TA-5) resulted in a uniform particle size distribution. The plywood prepared with Ag-TA-5 provided the highest dry and wet shear strength at 1.95 ± 0.11 MPa and 1.38 ± 0.3 MPa, respectively. The water absorption and thickness swelling of this plywood remarkably decreased up to 10.99% and 6.79%, respectively. More importantly, the presence of Ag-TA in CMS/PVA adhesive successfully inhibited the invasion of mold and bacteria. Based on the cyclic delamination test, the adhesive bond durability of bio-adhesive containing Ag-TA-5 could meet the requirement of the AITC Test T110-2007 and was comparable to commercial adhesives. The added advantage of the prepared bio-adhesive was its synthesis from agro-waste products and possible economically viable production at industrial level.

Competitive adsorption mechanisms of pigments in sugarcane juice on starch-based magnetic nanocomposites

The pigments in sugarcane result the crystallised sucrose appears unsatisfactorily yellow. In this study, cationic tapioca starch (CTS)-functionalized magnetic nanoparticles (CTS@Fe₃O₄) were synthesized and used as adsorbents for the removal of undesirable pigments. The adsorption properties of CTS@Fe₃O₄ were investigated by a sugarcane juice colorant model consisting of caffeic acid (CA), gallic acid (GA) and melanoidin (ME). The equilibrium adsorption capacities of CTS@Fe₃O₄ for CA, GA, and ME were 185, 160 and 580 mg g^-1 at the optimal conditions (60, 60 and 180 mg L^-1 initial concentrations, respectively; 0.3 mg mL^-1 CTS@Fe₃O₄ dosage, 313 K temperature, and pH value of 7). The adsorption process was described well by second-order kinetic and Langmuir isotherm models with a high fitting correlation coefficient approaching 1, suggesting that the pigments formed a surface monolayer with a homogenously distributed adsorption energy and was mainly dominated by chemisorption. The thermodynamic parameters (Gibbs free energy <0, enthalpy >0, and entropy >0) revealed that the adsorption process was endothermic and spontaneous. For the binary system, the competitive adsorption between pigments was primarily antagonistic. The speed of adsorption was the main factor affecting competitive adsorption, and the additional adsorption force reduced the effects of coexisting adsorbates.

Synthesis and Characterization of Gamma Radiation Induced Diallyldimethylammonium Chloride-Acrylic Acid-(3-Acrylamidopropyl) Trimethylammonium Chloride Superabsorbent Hydrogel

The gamma radiation technique is simple and time-saving for the synthesis of pure hydrogels. The present work focuses on synthesizing and characterizing Diallyldimethylammonium Chloride-Acrylic acid-(3-Acrylamidopropyl) trimethylammonium Chloride (DADMAC-AAc-APTAC) superabsorbent hydrogels. The hydrogels were synthesized by applying gamma radiation of different doses (2 kGy to 30 kGy) to two different compositions of monomers. The equilibrium swelling was found to be 33483.48% of dried gel for a 1:0.5:1 composition ratio of monomers at a 2 kGy radiation dose. Therefore, on the basis of equilibrium swelling, 2 kGy is the optimum radiation dose for synthesizing the hydrogel. Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR) spectroscopy, and X-ray diffraction (XRD) characterization techniques were used to analyze and confirm the structure of the hydrogel. Thermogravimetric analysis (TGA) and Scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS) clearly showed the thermal stability and surface morphology of the gel. Therefore, it can be concluded that hydrogels can be used in metal adsorption, drug delivery, and other fields of study.

A Novel Starch from Talisia floresii Standl Seeds: Characterization of Its Physicochemical, Structural and Thermal Properties

Colok seed (Talisia floresii Standl) represents 80% of the total fruit weight and is obtained from trees that grow mainly in Yucatan Peninsula. The aim of this work was the physicochemical characterization from colok starch seeds as an alternative to conventional sources and to identify its characteristics for potential applications in different industrial sectors. Starch yield was 42.1% with low levels of lipids, ashes and fibers. The amylose content was 33.6 ± 1.15%. The gelatinization temperature was 85 ± 0.25 °C. Color analysis resulted in a starch with an intermediate luminosity, reflecting a dark color. Finally, in morphology, starch granule exhibited an average size of 18.7 μm, spherical, uniform and without fractures. Overall results demonstrated that isolated colok starch can be used in food products that require high processing temperatures, such as sauces, cookies, noodles, bread and food packages.

Starch-based magnetic nanocomposite as an efficient absorbent for anticancer drug removal from aqueous solution

In this study, carboxymethyl cassava starch (CMCS)-functionalized magnetic nanoparticles (CMCS@Fe₃O₄) were synthesized via a simple one-pot co-precipitation method using CMCS materials with varying degrees of substitution, and used for the adsorption/removal of doxorubicin hydrochloride (Dox; a clinically available anti-cancer drug) from aqueous solution. The adsorption of Dox was studied using experimental conditions with varied pH, temperature, initial Dox concentration, and CMCS@Fe₃O₄ dosage. The CMCS@Fe₃O₄ adsorbents were characterized by scanning electron microscopy, transmission electron microscopy, infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and vibrating sample magnetometry. Each CMCS@Fe₃O₄ adsorbent exhibited a cubic inverse spinel iron oxide phase, small particle size, favorable magnetic properties, and good thermal stability. Batch adsorption experiments showed that the Dox adsorption efficiency reached 85.46% at a CMCS@Fe₃O₄ concentration of 20 mg mL^-1 at 303 K in pH 7.0. The adsorption experimental results indicated that the adsorption kinetics followed a pseudo-second-order model and the Langmuir equation. Considering the environmentally nontoxic nature of Fe₃O₄ and starch, the CMCS@Fe₃O₄ material demonstrated significant potential for removing Dox from aqueous solution and in magnetic targeted drug delivery systems for synergistic tumor treatments.