Effect of oxidation level on the inclusion capacity and solution stability of oxidized amylose in aqueous solution

Effects of ultrasonic and chemical dual modification treatments on the structural, and properties of cornstarch

This study aimed to explore the changes in the structural and functional properties of cornstarch modified by oxidation, esterification, and cross-linking under ultrasonic pretreatment. FT-IR and XRD characteristic peaks revealed successful access to chemical functional groups. Both ultrasonic and the three chemical treatments eroded the surface of starch granules, reducing their particle size and increasing their RC. Meanwhile, the destruction of the granules was further enhanced by the dual modification treatments. The ultrasonic pretreatment synergized and improved the swelling power, solubility, and translucency of all three chemical treatments. Further, it improved the poorer freeze-thaw stability of cross-linked starch, resulting in a lower water precipitation rate. In addition, both ultrasonic and chemical treatments significantly decreased RDS and SDS, and increased RS content. The ultrasonic-chemical dual modification had a synergistic effect on in vitro digestibility, resulting in a further increase in RS. In conclusion, this study provided ideas for developing new starch modification technology and deep processing of cornstarch, expanding its application areas and thus meeting the different needs of starch-based products.

Tuning a green carboxymethyl cellulose-based pre-tanning agent via peroxide oxidation for high chrome exhaustion in leather industry

The low chrome uptake by collagen in the conventional tanning process leads to the pollution of the wastewater. Due to environmental concerns, leather scientists are already searching for innovative ways to produce pre-tanning agents as a high exhaustion chrome tanning auxiliary. Herein, a novel kind of pre-tanning agent is engineered by converting carboxymethyl cellulose (CMC) to oxidized carboxymethyl cellulose (OCMC) via the hydrogen peroxide process. FT-IR and carboxyl content analysis demonstrated the increase in carboxyl content after oxidation. After that, the obtained OCMC was utilized as a pre-tanning agent, resulting in a high exhaustion of chrome (92.76 %) which is 27.76 % more than conventional chrome tanning (65 %), and the amount of chrome in wastewater reduced to 7.24 %. The hydrothermal stability of wet-blue increased by increasing the uptake of chrome (Ts = 118 °C). The obtained crust leather represented excellent mechanical properties (Tensile strength: 305.68 kg/cm2; tear strength: 50 kg/cm) and desirable organoleptic properties. The environmental analysis signifies a significant step towards a cleaner and sustainable tanning process (COD = 1600, BOD5 = 560 mg/L) compared to the conventional chrome tanning process. Consequently, the obtained results offer a green pre-tanning agent to meet the requirements of the sustainable development of the leather industry.

Emulsion template fabricated gelatin-based scaffold functionalized by dialdehyde starch complex with antibacterial antioxidant properties for accelerated wound healing

Gelatin and starch are considered as promising sustainable materials for their abundant production and good biodegradability. Efforts have been made to explore their medical application. Herein, scaffolds based on gelatin and starch with a preferred microstructure and antibacterial antioxidant property were fabricated by the emulsion template method. The dialdehyde starch was firstly combined with silver nanoparticles and curcumin to carry out the efficient hybrid antibacterial agent. Then, the gelatin microsphere of appropriate size was prepared by emulsification and gathered by the above agent to obtain gelatin-based scaffolds. The prepared scaffolds showed porous microstructures with high porosity of over 74 % and the preferred pore sizes of ∼65 μm, which is conducive to skin regeneration. Moreover, the scaffolds possessed a good swelling ability of over 640 %, good degradability of over 18 days, excellent blood compatibility, and cell compatibility. The promising antibacterial and antioxidant properties came from the hybrid antibacterial agent were affirmed. As expected, the gelatin-based scaffolds fabricated by the emulsion template method with a preferred microstructure can facilitate more adhered fibroblasts. In summary, gelatin-based scaffolds functionalized by starch-based complex expanded the application of abundant sustainable materials in the biomedical field, especially as antibacterial antioxidant wound dressings.

Encapsulation of luteolin using oxidized lotus root starch nanoparticles prepared by anti-solvent precipitation

In this study, luteolin-oxidized lotus root starch (OLRS) nanoparticles (NPs) were developed to improve the stability and antioxidant activity of luteolin. Results showed that a stable luteolin-OLRS NPs was formed using luteolin and OLRS (oxidation degree, 15%) in the weight ratio of 3:1, as well as anti-solvent and solvent in the volume ratio of 10:1. Under this condition, the particle size, polydispersity index and zeta-potential of luteolin-OLRS NPs was 305 nm, 0.173 and -20.8 mV, respectively. The analysis of transmission electron microscopy, X-ray diffractometer and Fourier transform infrared spectroscopy demonstrated that the luteolin was successfully encapsulated in OLRS NPs, giving an encapsulation efficiency of 87.2%. The release characteristic and antioxidant activity of encapsulated luteolin were further investigated. Results exhibited that the OLRS NPs enabled luteolin to be stable in simulated gastric fluid and sustained release in simulated intestinal fluid, leading to the enhancement of antioxidant activity of luteolin.

Rapid Gelling of Guar Gum Hydrogel Stabilized by Copper Hydroxide Nanoclusters for Efficient Removal of Heavy Metal and Supercapacitors

In this paper, guar gum (GG) hydrogel has been successfully prepared by adding GG and Cu2+ mixture into an alkaline medium. The formation mechanism of the hydrogel has been investigated through various techniques. Results reveal GG facilitates the formation of ultrafine copper hydroxide clusters with a diameter of ∼3 nm. Moreover, these nanoclusters bring about a rapid gelling of GG within 10 ms. The synthesized hydrogel is applied to the adsorption of heavy metal ions from wastewater. The hydrogel shows excellent removal efficiency in removing various heavy metal ions. Besides, the hydrogel derived porous carbon exhibits high specific capacitance (281 F/g at 1 A/g) and excellent rate capacity. The high contaminant removal efficiency character and excellent electrochemical performance endow GG hydrogel with potential applications in the environmental and energy storage field.

Preparation of high-strength and high-toughness biomass medical films based on a polydopamine dynamically united calcium alginate/carboxymethyl chitosan dual network

A high-strength and high-toughness biomass medical film was prepared using a polydopamine dynamically united calcium alginate/carboxymethyl chitosan dual network.

Oxidized starch cross-linked porous collagen-based hydrogel for spontaneous agglomeration growth of adipose-derived stem cells

Many strategies have been employed to artificially reconstruct adipose tissue in tissue engineering. The functionalization and survival of reconstructed adipose tissue depend on sufficient angiogenesis. Notably, agglomeration growth of adipose-derived stem cells (ASCs) is beneficial to promoting angiogenesis. Herein, we present a porous collagen-based hydrogel for spontaneous agglomeration growth of ASCs to promote angiogenesis. Oxidized starch with different oxidation degree was prepared and used to cross-link collagen to fabricate the porous hydrogel. The gelation time and pore size of hydrogels can be controlled by adjusting the oxidation degree of starch. Crosslinking enhances the mechanical properties, inhibits the swelling and biodegradation of the hydrogels. The hydrogels possess good blood compatibility and cytocompatibility. Significantly, ASCs tended to adhere to the hydrogels and spontaneously grew into spheres along with time. Effective expression of vascular endothelial growth and fibroblast growth factors were observed. Overall, the hydrogels have application prospects in vascularized adipose tissue engineering.

Improving the properties of straw biomass rattan by corn starch

As a kind of renewable resource and natural biomass, starch has been widely used to substitute plastics in the modern industry and is regarded as one of the most promising biodegradable materials. The newly developmental rattan, straw biomass rattan (SBR) as weaving material, has been exploited as per our previous work, which possessed advantages of both natural rattan and pure plastic rattan. The main objective of the work was to improve the properties of SBR by corn starch (CS). Based on the manufacturing of the above composites, the experiments of SBR that enhanced with CS on mechanical properties, melting performance, hydroscopicity, thermogravimetric analysis, and microstructures were tested in this study. The results revealed that when the content of CS increased gradually within the range of 0, 3, 6, 9 12, and 15 wt.%, the mechanical properties and melt index of the composite both increased first and then decreased, with 6 to 12 wt.% as the optimal dosage range. In contrast, the water absorption of SBR kept increased in this range, indicating an easier biodegradable. With CS added, the microstructure of SBR was examined by scanning electron microscope and found the microscopic surfaces and sections to become smoother, and that could improve the compatibility and tenacity between the materials. As a result, CS in moderation can be used as a supplement to enhance SBR, and improve their characteristics which will enhance the mechanical properties of the composites for future perspectives.

Synthesis of silver nanoparticles using oxidized amylose and combination with curcumin for enhanced antibacterial activity

Many kinds of multi-drug-resistant microorganisms have appeared. Moreover, monotherapy is increasingly no longer adequate for many complicated bacterial infections. Therefore, development of efficient combination antibacterial agent is becoming crucial. Herein, we present a hybrid antibacterial agent with enhanced antibacterial activity and high aqueous dissolubility based on silver nanoparticles and curcumin. The silver nanoparticles were firstly synthesized using oxidized amylose as an environmentally friendly reducing agent and stabilizer. Then, curcumin was added into the above mixture to get the hybrid antibacterial agent. The hybrid antibacterial agent presented high dissolubility in aqueous solution and enhanced antibacterial activity. In addition, the hybrid antibacterial agent presented good antioxidant activity and cell compatibility. Overall, the developed hybrid antibacterial agent has a potential to combat multiple bacteria-induced infections of wound surfaces.

Effects of carboxyl and aldehyde groups on the antibacterial activity of oxidized amylose

Dialdehyde-amyloses, dicarboxyl-amyloses and dialdehyde-carboxyl-amyloses with different oxidation levels were prepared and used to study the effects of aldehyde and carboxyl groups on the antibacterial activity of oxidized amyloses. The results showed that dicarboxyl-amyloses presented antibacterial activity through acidic pH effect produced by carboxyl groups, which was easily reduced or eliminated by adjusting pH. Dialdehyde-amyloses possessed a broad-spectrum antibacterial activity owing to the reactivity of aldehyde groups rather than acidic pH effect. Aldehyde would irreversibly damage bacterial cell wall and cytoplasmic membrane, resulting in decay and death of bacterial cells. It is interesting that the antibacterial properties of dialdehyde-carboxyl-amyloses were improved to some extent compared to dialdehyde-amyloses. The improvement of antibacterial effect of dialdehyde-carboxyl-amyloses may be due to the increasing dispersibility endowed by carboxyl groups, which could effectively enhance the interaction between dialdehyde-carboxyl-amyloses and bacteria. As a result, carboxyl group could act as a promising synergistic group against bacteria with aldehyde group.

Modified Starch-Chitosan Edible Films: Physicochemical and Mechanical Characterization

Starch and chitosan are widely used for preparation of edible films that are of great interest in food preservation. This work was aimed to analyze the relationship between structural and physical properties of edible films based on a mixture of chitosan and modified starches. In addition, films were tested for antimicrobial activity against Listeria innocua. Films were prepared by the casting method using chitosan (CT), waxy (WS), oxidized (OS) and acetylated (AS) corn starches and their mixtures. The CT-starches films showed improved barrier and mechanical properties as compared with those made from individual components, CT-OS film presented the lowest thickness (74 ± 7 µm), water content (11.53% ± 0.85%, w/w), solubility (26.77% ± 1.40%, w/v) and water vapor permeability ((1.18 ± 0.48) × 10−9 g·s−1·m−1·Pa−1). This film showed low hardness (2.30 ± 0.19 MPa), low surface roughness (Rq = 3.20 ± 0.41 nm) and was the most elastic (Young’s modulus = 0.11 ± 0.06 GPa). In addition, films made from CT-starches mixtures reduced CT antimicrobial activity against L. innocua, depending on the type of modified starch. This was attributed to interactions between acetyl groups of AS with the carbonyl and amino groups of CT, leaving CT with less positive charge. Interaction of the pyranose ring of OS with CT led to increased OH groups that upon interaction with amino groups, decreased the positive charge of CT, and this effect is responsible for the reduced antimicrobial activity. It was found that the type of starch modification influenced interactions with chitosan, leading to different films properties.

Synthesis of oxidized β-cyclodextrin with high aqueous solubility and broad-spectrum antimicrobial activity

Oxidized β-cyclodextrins with different oxidation levels were prepared using hydrogen peroxide as the oxidant and copper sulfate as the catalyst. The physicochemical, antimicrobial and antifungal properties of oxidized β-cyclodextrin were systematically studied. The results showed that the oxidation level of oxidized β-cyclodextrin was successfully controlled by adjusting the dosage of hydrogen peroxide. The aqueous solubility of oxidized β-cyclodextrin was highly improved as expected. However, oxidation changed the morphology and partly reduced the crystallinity of oxidized β-cyclodextrin due to the introduced carbonyl and carboxyl groups. It is interesting that oxidized β-cyclodextrin presented a broad-spectrum antimicrobial activity, which was efficiently improved with the increasing oxidation level. Growth of A. niger spores was efficiently inhibited in the presence of oxidized β-cyclodextrin. Moreover, oxidized β-cyclodextrin could effectively extend the storage time of apple. In summary, oxidized β-cyclodextrin shows potential as antimicrobial and antifungal agents in food industry.

Using oxidized amylose as carrier of linalool for the development of antibacterial wound dressing

This study aimed to prepare antibacterial wound dressings based on collagen and linalool/oxidized amylose inclusion complex. Encapsulation with oxidized amylose was used as an effective way to introduce linalool into collagen matrix. Our results showed that the content of linalool in the composite dressings was efficiently increased thanks to the solubilization effect of oxidized amyloses. The developed composite dressings possessed porous structure. They had abilities to keep the wound in moist environment and meanwhile prevent the excess exudates accumulation. The incorporation of linalool conferred the composite dressings with excellent antibacterial activities as expected. Moreover, the composite dressing with the highest content of linalool presented enhanced blood compatibility and good cell biocompatibility. This composite dressing effectively promoted granulation tissue formation and accelerated wound healing. It effectively prevented inflammation in regenerated skin tissue and scar formation too. Overall, the developed antibacterial wound dressings hold great potential for use in wound healing applications.