Low Different Degrees Of Substitution Research Articles

Improving the emulsifying capacity of brewers' spent grain arabinoxylan by carboxymethylation

Arabinoxylan derived from brewers' spent grain was carboxymethylated, and the emulsifying capacity of carboxymethylated arabinoxylans (CMAX) with different degrees of substitution (DS) was investigated. Results showed that carboxymethylation greatly enhanced the emulsifying capacity and emulsion stability of CMAX compared to the initial arabinoxylan. CMAX developed decreased ζ-potential, higher hydrophilicity, and improved interfacial adsorption capacity. Consequently, the denser and stronger interface on the oil droplet was formed, and the stabilizing mechanism was altered. Moreover, CMAX with lower DS could effectively stabilize emulsions during storage at a concentration of 0.5 % and pH between 6 and 7. Higher DS, however, led to poorer emulsion stability and greater flocculation as a result of the fragile interface formed by excess intermolecular ionic force. The research found CMAX potential in emulsion stabilizing and further applications in food processing.

Effects of butyrylated lotus seed starch on small intestinal bacteria and short-chain fatty acid production in mice

With the highest utilization rates of all short-chain fatty acids (SCFAs), butyric acid (BA) is essential for human health. In this study, we investigated butyrylated lotus seed starch (LSB) effects on small intestinal bacteria and SCFA levels in mice. Mouse body weights, after lotus seed resistant starch (RS) and LSB of different degrees of substitution (DS) treatment for 4 weeks, showed no significant difference. LSB of low DS improved small intestine morphology. Relative Lactobacillaceae and Lachnospiraceae abundance was promoted, and several harmful genera e.g., Desulfovibrio were suppressed in LSB groups. From correlation analyses, BA production was negatively related to Bacteroides and Corynebacterium. In this study, we identified butyrylated starch effects on small intestinal bacteria and provided a foundation for designing functional dietary fibers, which induced high BA levels.

Effect of sulfated/carboxylated cellulose nanocrystals with different degrees of substitution on the morphology and electrochemical performance of polypyrrole electrodes

As a result of different extraction methods, CNCs bear different surface groups with different degrees of substitution (DS), which may affect the electrode properties when incorporated as the reinforcing template in conducting polymer electrodes. After depositing polypyrrole (PPy) electrodes with different CNCs as dopants, we found that the PPy/CNCs electrode structure and electrochemical performance were sensitive to the DS of CNCs sulfate groups, while variation in the DS of carboxylates did not have any significant effect. PPy/CNCs electrodes deposited with carboxylated CNCs and a low sulfate group DS showed a porous and interconnected structure, while PPy/CNCs electrodes deposited with carboxylated CNCs with a high sulfate DS had a dense structure. Higher areal capacitance, higher rate capability, and smaller resistance were achieved with PPy/CNCs electrodes deposited using CNCs bearing carboxylates and a low DS of sulfate groups on CNCs. Cycling studies showed that porous electrodes reduced their charge storage capacity over 3000 cycles, however, dense PPy electrodes prepared using high-sulfate DS CNCs increased their charge storage capacity by 715% (from 0.15 to 1.07 F cm−2) over the first 1200 cycles showing opening of the structure and better electrolyte perfusion. This capacitance then stayed constant for at least another 1700 cycles.

Structural changes of butyrylated lotus seed starch and its impact on the gut microbiota of rat in vitro fermentation

Starch acylated with short-chain fatty acids (SCFAs), as type 4 resistant starch, can transport specific SCFAs to the colon and promote intestinal health. The objective was to investigate the effect of butyrylated lotus seed starches (LSBs) with different degrees of substitution (DS) on gut microbiota and butyrate production in vitro fermentation and to construct the relationship with its structural changes. The results of substrate structure change showed that the amorphous region of LSBs hydrolyzed firstly, the content of the subcrystalline region increased, and the molecular weight decreased. LSBs with higher DS had better fermentation characteristics, and more butyric acid production. A certain abundance of beneficial gut microbiota was significantly promoted. The Lotus seed resistant starch (LRS) group produced butyrate mainly by promoting the proliferation of Romboutsia. LSBs with low and medium DS mainly produced butyric acid by promoting Clostridium. LSBs with high DS produced butyric acid by promoting Lactobacillus, and Ruminococcaceae, by inhibiting Enterococcus, and Bacteroides. The study clarified the mechanism of butyric acid production was LSB's targeting the gut microbiota, which provided a scientific basis for the development of new prebiotics with high butyric acid production.

Edible packaging from hydroxypropyl thermoplastic cassava starch, agar and maltodextrin blends produced by cast extrusion

SummaryEdible packaging from hydroxypropyl cassava starch with different degrees of substitution (DS), agar and maltodextrin films was produced by conventional cast extrusion. Microstructures showed hydrophobic agar aggregates (100–200 µm) dispersed in film matrices, giving nonsmooth surfaces that enhanced wettability (17%–31%). Higher DS increased interaction between agar and maltodextrin via hydrogen bonding due to greater plasticisation and enhanced formation of agar networks. Lower DS starch showed instability with lower tensile strength (23% of higher DS), giving poor processability that was greatly improved by agar (20%). Water vapour and oxygen permeability depended on microstructures and hydrophilic–hydrophobic properties of the matrices which were decreased by 25% and 58% with combined agar and maltodextrin, respectively. Crystallinity of the films depended on plasticisation, with enhanced mobility that reduced transparency. Agar and maltodextrin inhibited recrystallisation of starch. Findings suggested that higher DS starch and agar enhanced extrusion processability, while maltodextrin increased plasticisation and reduced network strength.

Nonfouling textiles with tunable antimicrobial activity based on a zwitterionic polyamine finish.

Antimicrobial finishes for textiles and other surfaces that act without the release of biocides to the environment (contact biocides) or by inhibiting microbial adhesion (antifouling action) are viewed as promising and environmentally friendly alternatives to current products. We have used polyvinylamine polymers that were functionalized with zwitterionic sulfobetaine side chains with different degrees of substitution (DS) for the finishing of poly(ethylene terephthalate) (PET) and cotton fabrics in a water-based pad-dry-cure process. After washing with different surfactants, a stable finish with total polymer add-ons of 0.2–0.5 wt% was achieved. The finished textiles efficiently inhibited the adhesion of proteins and bacteria to the surface even with a small DS as low as 20%. Textiles finished with polymers with a low DS also showed significant antibacterial activity, most notably against Staphylococcus aureus. Accordingly, textile finishes with either pure antiadhesive (DS > 50%) or combined antiadhesive and antibacterial properties (DS = 20–50%) are accessible using this approach.

Dissecting the conformational determinants of chitosan and chitlac oligomers.

Chitosan and its highly hydrophilic 1-deoxy-lactit-1-yl derivative (Chitlac) are polysaccharides with increasing biomedical applications. Aimed to unravel their conformational properties we have performed a series of molecular dynamics simulations of Chitosan/Chitlac decamers, exploring different degrees of substitution (DS) of lactitol side chains. At low DS, two conformational regions with different populations are visited, while for DS ≥ 20% the oligomers remain mostly linear and only one main region of the glycosidic angles is sampled. These conformers are (locally) characterized by extended helical "propensities". Helical conformations 32 and 21, by far the most abundant, only develop in the main region. The accessible conformational space is clearly enlarged at high ionic strength, evidencing also a new region accessible to the glycosidic angles, with short and frequent interchange between regions. Simulations of neutral decamers share these features, pointing to a central role of electrostatic repulsion between charged moieties. These interactions seem to determine the conformational behavior of the chitosan backbone, with no evident influence of H-bond interactions. Finally, it is also shown that increasing temperature only slightly enlarges the available conformational space, but certainly without signs of a temperature-induced conformational transition.

Effects of cationization of high amylose maize starch on the performance of starch/montmorillonite nano-biocomposites

In the present study, cationized high amylose maize starches (CS) with different degrees of substitution (DS) were prepared. The physical properties and microstructures of CS/montmorillonite (Mt and D1821Mt) films were investigated. Morphological analysis showed stronger intercalations of CS with hydrophilic montmorillonite (Mt) than with hydrophobic montmorillonite (D1821Mt). For CS/Mt nanocomposite films, an increasing exfoliation trend was detected with the increase in DS. On the whole, the tensile strength of CS/Mt nanocomposite films decreased while water vapor permeability increased with an increase of DS. The CS/Mt film with the DS of 0.04 showed the highest tensile strength (14.01 MPa) and lowest water vapor permeability (1.80 × 10−10 g m/m2 s Pa). Rheological measurements confirmed that the intermolecular forces between CS and Mt decreased with increasing DS. Mt could obviously increase the thermal stability of the films. Overall, CS with lower DS had better compatibility with Mt, which helped improve the properties of CS/Mt nanocomposite films.

N-[4-(N,N,N-trimethylammonium)benzyl]chitosan chloride: Synthesis, interaction with DNA and evaluation of transfection efficiency

А novel cationic chitosan derivative, N-[4-(N,N,N-trimethylammonium)benzyl]chitosan chloride (TMAB-CS), with different degrees of substitution (DS) was synthesized by a chemoselective interaction of 4-formyl-N,N,N-trimethylanilinium iodide with chitosan amino groups using a reductive amination method. Several factors (pH, reactant ratio, reaction time, and chitosan structure) were studied for their effects on the DS of the resulting TMAB-CS. The obtained derivatives were characterized by 1H NMR and FTIR spectroscopy. Turbidimetric titration showed enhanced solubility over a wide pH range even for low-substituted TMAB-CS. TMAB-CS provided strong DS-dependent binding of plasmid DNA. Dynamic light scattering measurements revealed the formation of stable polyplexes with hydrodynamic diameters of 200–300nm and ζ-potential of 20–30mV. TMAB-CS with relatively low DS (25%) demonstrated more pronounced transfection efficiency (up to 2000 cell/cm2) of plasmid DNA into the HEK293 cell line promoted by free TMAB-CS. The positive effects of lower DS can be related to a better polyplex dissociation within the cell. The cytotoxicity of TMAB-CS was comparable to that of the initial chitosan at concentrations up to 300ng/μL, even at high DS.

Molecular dynamics simulations of the characteristics of sodium carboxymethyl cellulose with different degrees of substitution in a salt solution

Sodium carboxymethyl cellulose (SCMC) with different degrees of substitution (DS) possesses structural characteristics and physicochemical properties that are important in broad areas of industrial applications. This reported work investigated the structural characteristics, including the effective length (L ef), the radius of gyration (R g), and the hydrodynamic radius (R H), and the physicochemical properties, including intrinsic viscosity ([η]) and salt tolerance, of SCMC with a DS more than 1.0 in NaCl solution using molecular dynamics (MD) simulations. In the MD simulations, the DS of SCMC varied from 1.2 to 2.8, and the NaCl concentration varied from 0 to 1.4 mol/L. MD simulation results showed that with the increment of NaCl concentration, the L ef (or R g or R H) of SCMC decreased; with the increment of the DS, the L ef of SCMC increased. Also, the variation tendency of [η] in the NaCl solution was consistent with its L ef (or R g or R H). It was noted that the salt tolerance (represented by D) of SCMC increased as the DS increased. In addition, the sharp variation of the D value of SCMC occurred in the range of DS of 1.6 to 2.0, which agreed with the reported experimental results. Radial distribution function analyses showed that the Na+ cations had a stronger interaction with the carboxyl groups in SCMC with lower DS when it was present in a salt solution of higher concentration, which also reasonably explained the variation of L ef, R g, R H, [η], and D of SCMC in NaCl solution.

Curcumin encapsulated in the complex of lysozyme/carboxymethylcellulose and implications for the antioxidant activity of curcumin

A facile approach was investigated to encapsulate and protect curcumin (Cur) by self-assembly of lysozyme (Ly) and carboxymethylcellulose (CMC) of different degrees of substitution (DSs). This work studied the influence of Ly–CMC coacervates on the binding, solubility and stability of Cur. The interactions of Cur with Ly–CMC coacervates were researched by UV–vis, steady-state fluorescence, synchronous fluorescence and circular dichroism spectra. These results were explained in terms of the formation of Ly–CMC coacervates with electrostatic interaction, which led to unfold the structure of Ly for providing Cur with more hydrophobic microenvironment than free Ly. Meanwhile, the CMC of higher DS provide more negative charges, and produce more attraction to Ly than that of lower DS values. Moreover, the coacervates of Ly–CMC of higher DS are found to be superior for enhancing the stability of Cur. Our work provided a new insight for understanding the biomolecule protective system based on protein/polysaccharide complexes.

Study on effects of carboxymethyl cellulose lithium (CMC-Li) synthesis and electrospinning on high-rate lithium ion batteries

This study, for the first time, synthesized carboxymethyl cellulose lithium (CMC-Li) by a two-step method and applied it to modified electrode material by electrospinning and as a binder on a lithium ion battery. By electrospinning, nano CMC-Li fiber and CMC-Li/9, 10-anthraquinone (AQ) composite fiber were obtained successfully and coated AQ electrode material. AQ was uniformly distributed in fibers, and then CMC-Li/AQ composite fiber was carbonized to obtain the carbon nanofiber/AQ/Li [CAL] composite as lithium battery anode material. Also for the first time we investigated substituting aqueous CMC-Li with different degrees of substitution (DS) for oily polyvinylidene fluoride (PVDF) as a lithium battery binder to assemble the battery with CAL for electrochemical performance tests. Compared with PVDF binder, cells with CMC-Li for a binder have excellent advantages, such as higher discharge capacity (226.4 mAh g−1), safer cycle performance, lower cost and being more eco-friendly. Furthermore, the cell with CMC-Li with high DS performed better than the cell with low DS. This method also applies to other electrode materials.

Synthesis of new enzymatically degradable thermo-responsive nanogels

Two new families of thermo-responsive and enzymatically degradable nanogels were synthesized by batch emulsion polymerization of N-vinylcaprolactam (VCL) with dextran methacrylates (Dex-MA) with different degrees of substitution (DS). The first family was prepared using different amounts of Dex-MA with high DS forming highly cross-linked nanogel particles with the typical thermal behavior of PVCL-based nanogels: below the volume phase transition temperature (VPTT) nanogel particles were swollen and above it they were collapsed. After their enzymatic degradation with dextranase, nanogel particles swelled due to the cleavage of some glucopyranosyl bonds of dextran, but preserved their identity. On the other hand, the second family was prepared using different amounts of Dex-MA with low DS forming slightly cross-linked nanogel particles with an anomalous thermal behavior. Surprisingly, above the VPTT of the nanogel particles monodisperse interparticle reversible aggregates were formed. In addition, after their enzymatic degradation, a release of reducing sugars together with an intense de-swelling due to the fragmentation of the nanogel structure was observed. Both nanogel families could be suitable for drug delivery in tissues or organs where dextranase is present.

Characterization and evaluation of acylated starch with different acyl groups and degrees of substitution

Corn starch was modified with acetyl, propionyl and butyryl groups at four different degrees of substitution (DS). FTIR, X-RD, TG–DTA, SEM, swelling power, solubility, water binding capacity and light transmittance techniques were used to characterize the samples. Effect of DS and acyl groups on physico-chemical properties of starch was studied. During acylation, the crystalline structure of starch got destroyed and starch surface was eroded. Acylated starch was thermally stable than native starch. Amylose content of the starch samples increased slightly after acylation. Swelling power and water binding capacity of native starch were 3.09 g/g and 89.8%, respectively. In acetylated, propionylated and butyrylated starch at low DS, these properties increased. But at high DS, these decreased to below that of native starch. Butyrylated starch at DS of 1.75 showed lower swelling power, and water binding capacity than acetylated starch at DS 2.55. Increase in DS and acyl group chain length from acetyl to butyryl group improved hydrophobic transformation of starch.

Design, synthesis, and characterization of a combined main-chain/side-chain liquid-crystalline polymer based on ethyl cellulose

A novel combined main-chain/side-chain liquid-crystalline polymer based on an ethyl cellulose main chain containing azobenzene mesogens (AzoEC) was successfully synthesized. Molecular characterization of the resulting polymers with different degrees of substitution (DS) was performed with proton nuclear magnetic resonance (1H NMR), Fourier-transform infrared spectroscopy (FTIR), and gel permeation chromatography (GPC). Thermal stability was investigated by thermogravimetric analysis (TGA). The phase transitions and liquid-crystalline behavior of these polymers were investigated by differential-scanning calorimetry (DSC), polarized optical microscopy (POM), and wide-angle X-ray diffraction (WAXD). The results indicate that DS has substantial effect on the liquid-crystalline behavior of these polymers. AzoEC with low DS only shows the cholesteric phase similar to ethyl cellulose (EC). However, when DS increases to a specific value, AzoEC begins to show fascinating supramolecular structures. The supramolecular structure of AzoEC with maximum DS consisted of a large-scale ordered lamellar structure formed by EC main chains and a small-scale ordered structure formed by azobenzene mesogens.

Physicochemical properties of octenyl succinic anhydride‐modified potato starch with different degrees of substitution

Esterified starch is an important type of modified starch. In particular, octenyl succinic anhydride-modified starch (OSA starch) is widely used in the food industry. However, there has been little research on the properties of products with different degrees of substitution (DS). Therefore the aim of this study was to analyse the physicochemical properties of products with different DS. OSA starch samples with different DS were prepared from potato starch. Two new peaks were observed in the Fourier transform infrared spectrum, one at 1724 cm(-1) due to C==O and one at 1572 cm(-1) due to RCOO--. Emulsifying capacity and emulsion stability improved with increasing DS. Rheological analysis showed the occurrence of the 'shear-thinning' phenomenon, the viscosity of the sample with DS = 0.0211 being even lower than that of native starch. A decrease in syneresis rate from 88.3% (native starch) to 39.0% (DS = 0.0211) indicated that freeze-thaw stability was improved. The physicochemical properties of OSA potato starch were better than those of native potato starch. Freeze-thaw stability, emulsifying capacity and emulsion stability improved with increasing DS. Viscosity increased at lower DS but decreased at DS = 0.0211.

The influence of metal cations on the behaviour of carboxymethyl celluloses as talc depressants

Abstract Metal cations have been shown to depress the floatability of siliceous minerals indicating an interaction with the mineral surface. In this work, the effect of metal cations on the interaction of sodium carboxymethyl cellulose (CMC) depressants and talc has been studied. Equilibrium adsorption and microflotation studies were conducted on pure talc with a range of ions (Ca 2+ , Mg 2+ , K + ) and ionic strengths, using CMCs of two different degrees of substitution (DS). In order to probe the effect of the ions on the polymer molecules themselves, intrinsic viscosity measurements were made where the ionic strength (IS), pH and type of ion were varied. The results of the adsorption studies showed that the divalent cations Ca 2+ and Mg 2+ were far more efficient at promoting adsorption on to the talc surface than the monovalent K + ion. The higher DS CMC had a much more stringent requirement than the low DS CMC for the presence of high ionic strength electrolyte in order to achieve good adsorption. The microflotation studies complemented these results and showed that talc was more efficiently depressed by CMCs when Ca 2+ and Mg 2+ ions were present than when only K + was present and that the high DS CMC was less efficient at the ionic strength used than the lower DS CMC. Intrinsic viscosity measurements of a CMC in different ionic strength solutions of K + and Ca 2+ ions showed that over a wide pH range, Ca 2+ ions caused the CMC molecule to coil more than the K + ions. This is in keeping with the observed increase in adsorption density on the talc surface with Ca 2+ ions and subsequent improvement in the depressant activity. These results were complemented by those from size exclusion chromatography with triple detection where the light scattering data revealed that for a solution of CMC of DS 0.78 in 10 −2 IS Ca(NO 3 ) 2 the radius of gyration was 28% smaller than in 10 −2 IS KNO 3. The adsorption studies show however, that at high ionic strength (10 −1 ), when the CMCs are fully coiled, the enhancement of bonding due to Ca 2+ and Mg 2+ ions is still significantly greater than for K + ions, which implies that there is also an interaction between the CMCs and the divalent ions on the talc surface which increases CMC adsorption and facilitates depression.

Physicochemical properties of Pinhão ( Araucaria angustifolia, Bert, O. Ktze) starch phosphates

Physicochemical properties of pinhão (seeds of Paraná pine) starch phosphates were evaluated and compared to corn starch phosphates. The phosphorylation process used yielded starch phosphates with three different degrees of substitution (DS): low (0.015), medium (0.07) and high (⩾0.12). Medium and high DS starch phosphates had higher cold water binding capacity, swelling power, and paste clarity, but lower paste syneresis (at 5 °C and after freeze–thaw cycles) than native starches ( P<0.05). Low, medium, and high DS corn starches had higher solubility than native starches (3.8-, 8-, and 6-fold higher; P<0.05), but the solubility of pinhão starch increased only in medium DS starch phosphates (3-fold higher; P<0.05). Low DS starch phosphates had viscosity curves similar to native starches. In contrast, medium and high DS starch pastes had peak viscosity at room temperature, reached the minimum viscosity when heated to 95 °C, and had low setback.

Preparation and antimicrobial activity of hydroxypropyl chitosan

Water-soluble hydroxypropyl chitosan (HPCS) derivatives with different degrees of substitution (DS) and weight-average molecular weight ( M w) were synthesized from chitosan and propylene epoxide under basic conditions. Their structure was characterized by IR spectroscopy, NMR spectroscopy, and elemental analysis, which showed that both the OH groups at C-6 and C-3 and the NH 2 group of chitosan were alkylated. The DS value of HPCS ranged from 1.5 to 3.1 and the M w was between 2.1 × 10 4 and 9.2 × 10 4. In vitro antimicrobial activities of the HPCS derivatives were evaluated by the Kirby–Bauer disc diffusion method and the macrotube dilution broth method. The HPCS derivatives exhibited no inhibitory effect on two bacterial strains ( Escherichia coli and Staphylococcus aureus); however, some inhibitory effect was found against four of the six pathogenic fruit fungi investigated. Some derivatives (HPCS1, HPCS2, HPCS3, HPCS3-1, and HPCS4) were effective against C. diplodiella and F. oxysporum. HPCS3-1 is the most effective one with MIC values of 5.0, 0.31, 0.31, and 0.16 mg/mL against A. mali, C. diplodiella, F. oxysporum, and P. piricola, respectively. Antifungal effects were also observed for HPCS2 and HPCS3-1 against A. mali, as well as HPCS3 and HPCS3-1 against P. piricola. The results suggest that relatively lower DS and higher M w value enhances the antifungal activity of HPCS derivatives.