Similar Degree Of Substitution Research Articles

Correlation between emulsification and butyryl group distribution in various butyrylated starches

Butyrylated starch, a modified starch with significant applications in the food and pharmaceutical industries, lacks sufficient research on its emulsification. In this study, butyrylation was performed using waxy corn starch, tapioca starch and corn starch as raw materials, and their group distribution were determined. X-ray photoelectron spectroscopy (XPS), Raman microscopy and water contact angle measurements showed that the distribution of butyryl group in B-WCS was highly uniform. The results of the emulsification assay illustrated that B-WCS exhibited significant emulsifying potential at similar degrees of substitution. Analysis of the interface behavior demonstrated that B-WCS reduced the oil-water interfacial tension and formed a rigid interface film that resisted external deformation, thereby maintaining emulsion stability. This indicates that B-WCS exhibiting a highly uniform group distribution has significant emulsification potential. This study revealed the emulsification mechanism of butyrylated starch from an interface perspective and analyzed the relationship between the butyryl group distribution and emulsifiability.

Fingerprinting of hydroxy propyl methyl cellulose by comprehensive two-dimensional liquid chromatography-mass spectrometry of monomers resulting from acid hydrolysis

Hydroxypropyl methyl cellulose (HPMC) is a type of cellulose derivative with properties that render it useful in e.g. food, cosmetics, and pharmaceutical industry. The substitution degree and composition of the β-glucose subunits of HPMC affect its physical and functional properties, but HPMC characterization is challenging due to its high structural heterogeneity, including many isomers. In this study, comprehensive two-dimensional liquid chromatography-mass spectrometry was used to examine substituted glucose monomers originating from complete acid hydrolysis of HPMC. Resolution between the different monomers was achieved using a C18 and cyano column in the first and second LC dimension, respectively. The data analysis process was structured to obtain fingerprints of the monomers of interest. The results revealed that isomers of the respective monomers could be selectively separated based on the position of substituents. The examination of two industrial HPMC products revealed differences in overall monomer composition. While both products contained monomers with a similar degree of substitution, they exhibited distinct regioselectivity.

Acylated resistant starches: Changes in structural properties during digestion and their fermentation characteristics

Acylated resistant starches have great potential in improving body health due to their special short-chain fatty acids (SCFAs) releasing abilities. The purpose of this study was to investigate the changes in structural properties of acylated starches before and after digestion, and to further reveal their in vitro fermentation characteristics. Acetylated, propionylated, and butyrylated maize starches (MSA, MSP, and MSB, respectively) with similar degrees of substitution (DS) were obtained. The acyl groups were distributed on both the surface and the inner regions of the starch granules. During the digestion, partial acyl groups of MSA, MSP, and MSB were lost, and their DS values decreased from 0.145, 0.164, and 0.185 to 0.066, 0.049, and 0.137, respectively. The average degree of polymerization decreased after acylation and further decreased after digestion, indicating the breakage of the long chains. In the in vitro fermentation stage, acylated starches increased the total SCFAs concentrations when compared to native starch. The introduced acyl groups of the three acylated starches could be effectively released. Moreover, MSP and MSB had more pronounced effect on promoting the release of specific SCFAs than MSA. The current study contributes to understanding the mechanism of functional resistant starch and enriching its applications in functional foods.

Preparation and characterization of cationic hyperbranched maltodextrins as potential carrier for siRNA encapsulation

The present study sought to investigate the physicochemical properties of cationic branched maltodextrins with similar degrees of substitution but different degrees of branching and their siRNA delivery capacity. The results showed that the ratio of α-1,6 glycosidic bonds was significantly increased in the sample treated with dual enzymes. The structural characterization results showed that abundant short chains reassembled by 1,4-α-glucan branching enzyme (GBEs) hydrolysis formed hyperbranched short clustered structure. The absorption peaks that appeared in the FT-IR spectrum confirmed the occurrence of quaternization. The complexes formed by self-assembly of cationic maltodextrins and siRNA were verified by the gel retardation assay and atomic force microscopy, demonstrating a uniform spherical structure with a size close to 300–350 nm. Meanwhile, cationic branched maltodextrins could effectively reduce the change of secondary structure of siRNA. Overall, the results suggested that branched maltodextrins with a cationic surface had significant potential as siRNA carriers.

Butyl Group Distribution, Intestinal Digestion, and Colonic Fermentation Characteristics of Different Butyrylated Starches.

Despite being a promising butyrate carrier, butyrylated starch remains poorly understood in terms of the correlation between starch structure and fermentation characteristics. Herein, three butyrylated starches derived from different botanical sources were prepared with a similar degree of substitution. Raman microscopy and water contact angle analysis suggested that a relatively large proportion of butyl group substitutions occurred within the interior of butyrylated waxy maize starch (B-WMS) granules. In vitro digestion results showed that branch points provided butyl groups with a specific protection from enzymatic hydrolysis, whereas butyl groups significantly increased the resistant starch content of butyrylated starch. Moreover, the porous morphology with less distributed butyl groups on the granular surface contributed to a faster fermentation rate in B-WMS. The current study reveals the influence of botanical origin on butyl group distribution, which in turn plays a pivotal role in regulating the intestinal digestion and colonic fermentation of butyrylated starch.

In situ sol-gel synthesis of hyaluronan derivatives bio-nanocomposite hydrogels.

The main driving idea of the present study was the comparison between two different chemical modifications of hyaluronic acid (HA) followed by the development of nanocomposite hydrogels directly in situ by biomineralization of photocrosslinkable HA polymers through sol-gel synthesis. In this way, it has been possible to overcome some limitations due to classical approaches based on the physical blending of inorganic fillers into polymer matrix. To this aim, methacrylated and maleated HA, synthesized with similar degree of substitution (DS) were compared in terms of mechanical and physico-chemical properties. The success of in situ biomineralization was highlighted by reflect Fourier transform infrared spectroscopy and thermogravimetric analysis. Furthermore, mechanical characterization demonstrated the reinforcing effect of inorganic fillers evidencing a strong correlation with DS. The swelling behavior resulted to be correlated with filler concentration. Finally, the cytotoxicity tests revealed the absence of toxic components and an increase of cell proliferation over culture time was observed, highlighting these bio-nanocomposite hyaluronan derivatives as biocompatible hydrogel with tunable properties.

Superabsorbent Hydrogels From Rice Starches With Different Amylose Contents

Bio‐based superabsorbent hydrogels from rice starches are prepared and characterized. Three rice starches with different amylose contents are carboxymethylated to obtain carboxymethyl rice starches (CMRS) with similar degrees of substitution. The hydrogels are then prepared from CMRS using citric acid as a cross‐linker. The chemical structure of CMRS and the formation of ester linkages in the hydrogels are confirmed by Fourier transform infrared spectroscopy (FTIR). Scanning electron microscope (SEM) reveal that rice starch hydrogels had a three‐dimensional interconnected porous structure. Free swelling capacity and absorbency under load (AUL) of the hydrogels are investigated. The results suggest that regardless of amylose content, the three rice starches yield hydrogels with similar characteristics. Amylose content appears to have a certain effect on mechanical strength but not on the free swelling capacity of the hydrogels.

Effect of β-glucan-fatty acid esters on microstructure and physical properties of wheat straw arabinoxylan films

Arabinoxylans (AX) was isolated from wheat straw, whereas β-glucan (BG) was extracted from oat flour. The compositional analysis indicated wheat straw AX contained arabinose and xylose as major constituent sugars whereas higher β-glucan content (77%) was found in the extracted material from oat flour. The BG was conjugated with lauric (LA), myristic (MA), palmitic (PA), stearic (SA) and oleic (OA) acid to prepare corresponding β-glucan-fatty acid esters (BGFAs) with nearly similar degree of substitution. The effect of BGFAs to AX films on the water barrier, optical and mechanical properties were investigated. The addition of LABG and MABG to AX formed laminar structures in the composite films which limited water vapor permeability, giving rise to more opacity. Films prepared by blending AX with SABG and OABG were less effective as water vapor barrier due to their non-layer film microstructures; however they were less opaque. The laminar structures also imparted less mechanical strength and flexibility in the composite films. Furthermore, thermogravimetric analysis (TGA) revealed that all AX-BGFAs composite films were thermally more stable than pure AX and AX-BG films.

カルド修飾CNF/PLAコンポジット材料の力学的・熱的物性評価研究(II)

In our previous paper, we reported that the cellulose nano-fiber (CNF) treated with Cardo material (BPFG), referred to as B-CNF, dispersed finely in an organic solvent as well as in polylactic acid (PLA) matrix, and the mechanical properties (especially at the temperature region above the grass transition temperature, Tg) of PLA/CNF composites were improved with the amount of B-CNF content (0.3, 0.5, and 1.1 wt%) in the composites. However, the degree of substitution of BPFG on CNF was only 8.6 wt% (18.6 mmol%) and the effect of the substitution of BPFG was not determined. In this study, we prepared several B-CNF with various degrees of substitution to BPFG and examined the effect of the substitution on the mechanical properties of PLA/B-CNF composites. Moreover, we also prepared the CNF treated by Bisphenol-A diglycidyl ether (BPAG), which does not have Cardo structure in its chemical structure, and determined the effect of the difference in chemical structure (with/without Cardo structure) on their mechanical properties at high temperature. Master batches were prepared by mixing CNF and PLA in an organic solvent and then they were further blended with PLA in a kneader at 150 °C. TEM observation revealed that both of the CNF treated with BPFG (B-CNF) and that treated with BPAG (BisA-CNF) dispersed homogeneously in the PLA. The storage moduli of B-CNF/PLA composites above Tg increased with the degree of BPFG substitution. The storage moduli of B-CNF/PLA and BisA-CNF/PLA with similar degree of substitution were about 5 times higher than that of neat PLA above Tg, and the modulus of B-CNF/PLA was slightly higher than that of BisA-CNF/PLA. Moreover, the peak intensity of tanδ of B-CNF/PLA and BisA-CNF/PLA were lower than that of neat PLA, and the intensity of tanδ of B-CNF/PLA was lower than that of BisA-CNF/PLA. These results suggest that the molecular motion of PLA was restricted by the presence of B-CNF and BisA-CNF because the interaction between PLA and B-CNF or BisA-CNF is much stronger than that in untreated CNF/PLA. Furthermore, B-CNF improved the mechanical properties of the composite more effectively than BisA-CNF for the PLA composite above Tg. From the result of Coefficient of Thermal Expansion (CTE) measurements, we estimated the volume fraction of PLA phase interacting with B-CNF and BisA-CNF by means of the “mixtures rule”. As a result, it was found that the PLA phase interacting with of B-CNF/PLA is larger than that in BisA-CNF/PLA. This may be one of the factor which caused the difference in their mechanical properties of B-CNF/PLA and BisA-CNF/PLA. Finally, CTE measurements revealed that there is a strong relation between the intensity of tanδ at Tg and the volume fraction of the PLA interacting phase in PLA matrix.

Conversion of agricultural residues to carboxymethylcellulose and carboxymethylcellulose acetate

In view of continuing interest in the utilization of agricultural by-products, we have converted cellulose, wheat straw, barley straw, and rice hull into carboxymethylcellulose (CMC), using both conventional heat and microwave-assisted synthesis. The application of microwave technology has enabled an improved synthesis of CMC to be conducted, with similar degrees of substitution as conventional heat (3h) but reduced reactions times (30min). The CMC obtained can be acetylated to form carboxymethylcellulose acetate (CMC acetate). The FT-IR and solid state 13C NMR spectra of these materials have been characterized. With variations in the degrees of substitution of carboxymethyl and acetyl groups, a family of CMC acetate products can be made. The polymer may perhaps find applications as filtration membranes, functional fillers in polymers, and additives in commercial formulations.

Evaluation of the technological and sensory properties of durum wheat spaghetti enriched with different dietary fibres.

The incorporation of fibres, whether insoluble or soluble, in durum wheat pasta negatively impacts desirable end-use properties, especially if incorporated in significant amounts. Fibres can disrupt the starch-protein matrix of the dough during pasta preparation and can also often swell more readily with water than starch, competing with the starch for water during dough development. Similar degrees of substitution with different fibres gave markedly different impacts on firmness, stickiness, cooking loss and sensory attributes, suggesting that results obtained for one fibre cannot readily be generalized to other fibres. The in vitro starch digestibility of the pastas was significantly reduced when resistant starch, β-glucan-enriched flour, carboxymethyl cellulose or guar gum was incorporated but increased when pollard or inulin was added. In many instances, different sources of the same fibre gave dramatically different impacts on the properties of cooked durum wheat pasta.

Interplay of Phase Separation and Thermoreversible Gelation in Aqueous Methylcellulose Solutions

Rheology and turbidity measurements were performed under similar thermal histories to probe the relationship between thermoreversible gelation and phase separation for a set of three methylcellulose (MC) materials with similar degrees of substitution (DS) and contrasting molecular weights after hydration in cold water. Frequency-independent loss tangents were used to identify the gel point (Tgel) in MC solutions well over the chain overlap concentration (c ≥ 10c*). Transmittance of 633 nm laser light through the solutions revealed that all MC solutions cloud upon gelling, with a relative transmittance of 86% closely associated with the gel point. The gelation temperature of MC solutions was found to decrease with increasing MC concentration and the results for all molecular weights superposed. Using gel and cloud points, a phase diagram was constructed which reveals that clear MC solutions transition directly into turbid gels. Frequency-independent storage moduli of fully developed MC gels scaled with φ2....

Effect of N-betainate and N-piperazine derivatives of chitosan on the paracellular transport of mannitol in Caco-2 cells

The effects of novel quaternary chitosan derivatives on the paracellular transport of mannitol and cell viability were studied in the Caco-2 cell model. The N-betainate derivative with the degree of substitution of 0.05 was very effective at 1.0% (w/v) concentration. The activity decreased as the degree of substitution increased. The cytotoxicity of N-betainates was rather low. The N-piperazines were at least equally effective as the N-betainates with a similar degree of substitution (>0.15). Most of the N-piperazines did not exert toxic effects on the cell monolayers. Overall, the inverse proportionality between the degree of substitution and activity suggests that an intact chitosan backbone is essential for the bioactivity of chitosan derivatives. The quaternary group does not substitute for the activity of the free amine group. In particular, the N-betainate derivatives of chitosan should contain only the minimum number of substituents required for water solubility.

Preparation of Starch Phosphates by Extrusion

ABSTRACTPhysicochemical properties were compared on starch phosphates of cassava and corn, prepared by an extrusion process and by the conventional method, as well as their native starches. Results indicated that for preparing starch phosphates with similar degrees of substitution, the extrusion process required less reagent than the conventional method. The starch phosphates showed similar responses to heat treatment and pH changes. However, the starch phosphates made by extrusion had lower gelatinization temperatures, lower enthalpies and lower paste viscosities than those prepared by the conventional method. This result could be attributed to the high degree of damaged starch in the extruded products.

HOMOGENEOUS BUTYRATION OF CELLULOSE DISSOLVED IN DIMETHYL SULFOXIDE-FORMALDEHYDE SYSTEM

Bleached sulfite pulp was dissolved with formaldehyde in dimethyl sulfoxide, and the optimum condition was determined in terms of sufficient dissolution and prevention of degradation of cellulose. Homogeneous acetylation of the cellulose dissolved was examined, and the cellulose acetates witl a degree of substitution up to 2.4 were obtained in recovery yield ca. 80%. The preparation of the cellulose acetate with a degree of substitution close to 3.0 was inferred to be difficult with the present method. The cellulose acetates with a degree of substitution 2.0-2.4 was found to be easily soluble in ethyleneglycol monomethyl ether and ethyl lactate, and practically soluble in acetone. The solubility of the cellulose acetate was found to be slightly poorer than that of partially saponified cellulose acetate with a similar degree of substitution, prepared from cellulose triacetate, suggesting that the degree of polymerization of the acetate was higher than that of the partially saponified one. The cellulose acetate film prepared from the ethyleneglycol monomethyl ether solution was slightly yellowish transparent, and brittle, but was hard and had rather high tensile strength. The results indicate that the cellulose acetate obtained with the present method may have a possibility for commercial application.

HOMOGENEOUS ACETYLATION OF CELLULOSE DISSOLVED IN DIMETHYL SULFOXIDE-FORMALDEHYDE SYSTEM

Bleached sulfite pulp was dissolved with formaldehyde in dimethyl sulfoxide, and the optimum condition was determined in terms of sufficient dissolution and prevention of degradation of cellulose. Homogeneous acetylation of the cellulose dissolved was examined, and the cellulose acetates witl a degree of substitution up to 2.4 were obtained in recovery yield ca. 80%. The preparation of the cellulose acetate with a degree of substitution close to 3.0 was inferred to be difficult with the present method. The cellulose acetates with a degree of substitution 2.0-2.4 was found to be easily soluble in ethyleneglycol monomethyl ether and ethyl lactate, and practically soluble in acetone. The solubility of the cellulose acetate was found to be slightly poorer than that of partially saponified cellulose acetate with a similar degree of substitution, prepared from cellulose triacetate, suggesting that the degree of polymerization of the acetate was higher than that of the partially saponified one. The cellulose acetate film prepared from the ethyleneglycol monomethyl ether solution was slightly yellowish transparent, and brittle, but was hard and had rather high tensile strength. The results indicate that the cellulose acetate obtained with the present method may have a possibility for commercial application.

Cellulase (β-1,4-glucan 4-glucanohydrolase) from the wood-degrading fungus Polyporus schweinitzii fr. : II. Characterization

1. 1. Some properties of an endocellulase (β-1,4-glucan 4-glucanohydrolase, EC 3.2.1.4), previously isolated from culture filtrates of the wood degrading fungus Polyporus schweinitzii Fr. have been investigated. 2. 2. The cellulase is stable between pH 2.6 and 7.5. Using a viscosimetric test with CM-cellulose as the substrate, an optimum activity was found at about pH 4.0, although only a very slight fall was observed at a lower pH. With an increasing pH above 4.0, the activity decreased sharply, and the enzyme is almost inactive above pH 6.0. 3. 3. The cellulase has an optimum activity at about 60° and is almost completely stable up to this temperature; at higher temperatures it is rapidly denatured. 4. 4. The molecular weight was determined on a calibrated Sephadex G-100 column and was found to be 45 000 ± 4 500. 5. 5. Dewaxed cotton cellulose is practically unattacked by the cellulase both before and after purification and after the addition of a mycelium extract, whereas a regenerated cellulose was readily degraded; the amorphous regions are preferentially attacked. 6. 6. It was found that hydroxyethylcellulose was more easily degraded than a CM cellulose with a similar degree of substitution and, in limited experiments with hydroxyethylcelluloses, that susceptibility to enzymatic attack is inversely proportional to the degree of substitution. 7. 7. The results are compared with those for cellulases from other sources and are discussed in relation to the behavior of P. schweinitzii in vivo.