Acetyl Content Research Articles

Chemical and Mechanical Differences between Historic and Modern Scots Pine Wood

Timber is one of the most common historic building materials, but relatively little is known about how it ages in situ. Here we investigate historic and modern Scots pine to determine any chemical or mechanical differences between them. Fourier-transform infrared (FTIR) microscopy was used to investigate differences in the chemical composition of Scots pine (Pinus sylvestris L.) timber, comparing small samples from historic beams about 500 years old with modern timber. The hemicellulosic acetyl content was reduced by about half in the historic samples, uniformly across the thickness of the beams. A chemical mechanism was therefore suggested for the loss of acetyl groups, as has been observed in paper. In paper, deacetylation and the resulting release of acetic acid are accompanied by loss of strength. Mechanical testing of the historic timber was difficult because the available length of the samples along the grain was only 20 mm. After developing a miniaturized compression test developed for the purpose, it was shown that the relative stiffness of the historic Scots pine samples was reduced by about half compared to modern material.

Sarcodia suieae acetyl-xylogalactan regulate RAW 264.7 macrophage NF-kappa B activation and IL-1 beta cytokine production in macrophage polarization

In this study, the effects of acetyl-xylogalactan extracted from Sarcodia suieae on RAW 264.7 macrophage polarisation were evaluated. This extracted acetyl-xylogalactan had a monosaccharide composition of 91% galactose and 9% xylose, with polysaccharide and acetyl contents of 80.6% and 19.3%, respectively. MALDI–TOF mass spectrometry and NMR spectroscopy revealed the molecular weight of the acetyl-xylogalactan to be 88.5 kDa. After acetyl-xylogalactan treatment, RAW 264.7 macrophage polarisation was noted, along with enhanced phagocytic ability. Furthermore, the Cell Counting Kit-8 (CCK-8) assay was performed and the results demonstrated non-significant alteration in lactate dehydrogenase levels in the treated cells. Next, interleukin (IL) 1β, TNF, and Malt-1 expression in RAW 264.7 macrophages treated with the S. suieae acetyl-xylogalactan was investigated through real-time quantitative polymerase chain reaction, and the results demonstrated that S. suieae acetyl-xylogalactan induced IL-1β and Malt-1 expression. RNA sequencing analysis results indicated the S. suieae acetyl-xylogalactan positively regulated cytokine production and secretion, protein secretion, and response to IL-1 activation, based on the observed GO terms. The predicted target genes in the GO enrichment analysis were found to upregulate NF-κB signalling and M0 to M1 macrophage conversion through the observed cytokine production. Thus, acetyl-xylogalactan can positively regulate RAW 264.7 macrophage polarisation.

Spectroscopic Interrogation of the Acetylation Selectivity of Hardwood Biopolymers

AbstractAcetylation of wood is an age‐old chemical platform known to improve its chemical and physical properties in direct correlation with the degree of acetylation. However, as of yet, no systematic study has been undertaken to probe the selectivity of acetylation of wood. A fundamental understanding of the molecular basis for acetylation of the constituent biopolymers, viz., holocellulose, and lignin for tropical hardwood, an emerging building material, is therefore undertaken. Wood samples are treated with acetic anhydride at 120 °C over a wide range of time periods. The degrees of acetylation and acetyl content of the tropical hardwood are measured to reveal that the acetyl content in which the hydroxyl groups of wood correspond to an increment in weight percent gain as confirmed by FT‐IR for individual wood biopolymers and whole wood. However, surprisingly,31P‐NMR establishes the order of reactivity for the hydroxyl groups as lignin > hemicelluloses > whole wood in direct opposition to their proportions in wood, but in correlation to their direct accessibilities and reactivities.

Steam explosion process for the selective extraction of hemicelluloses polymers from spruce sawdust

The aim of this work was to study the effect of steam explosion conditions (severity factor, pH of pre-soaking medium) on the extraction of high molecular weight hemicelluloses from spruce sawdust. The highest yields were obtained at severity factor of 3.65 (47 and 44 mg/g or dry wood in neutral and basic mediums respectively). Treatment at high severity gave lower yield with lower molecular mass. A high extraction selectivity of high molecular weight hemicelluloses was observed as a function of the medium of the impregnation step: after a basic impregnation, ∼90% of extracted hemicelluloses are arabinoglucuronoxylans (∼70 kDa) whereas after a water impregnation ∼85% of galactoglucomannans (∼28 kDa) were recovered. FTIR, HSQC 2D and acetyl content analysis show that the GGM isolated are highly acetylated, with an acetylation rate very closed to the values reported for native AcGGM.

Short communication: Stabilization of milk proteins at pH 5.5 using pectic polysaccharides derived from potato tubers

Potato pectin has unique molecular characteristics that differentiate it from commercially available pectins sourced from citrus peels or apple pomace, including a higher degree of branching and a higher acetyl content. The objective of this study was to evaluate the ability of potato pectin to stabilize milk proteins at an acidic pH above their isoelectric point, pH 5.5, at which no citrus- or apple-derived pectins are functional. Potato pectin was extracted from raw potato tubers by heating at pH 4.5 and 120°C for 30 min after removing starch solubilized using a dilute HCl solution adjusted to pH 2. The potato pectin was found to have a galacturonic acid content of 17.31 ± 3.29% (wt/wt) and a degree of acetylation of 20.20 ± 0.12%. A portion of the potato pectin was deacetylated by heating it in an alkaline condition. The deacetylation resulted in a galacturonic acid content of 19.12 ± 4.64% (wt/wt) and a degree of acetylation of 3.03 ± 0.03%. Particle size distributions in acidified milk drink (AMD) samples adjusted to pH 5.5 demonstrated that the acetylated and deacetylated potato pectins were capable of inhibiting the aggregation of milk proteins to the largest degree at a pectin concentration of 1.0 and 0.25% (wt/wt), respectively. Pectin molecules that were not bound to milk proteins in these AMD samples were quantified after centrifugally separating milk proteins and pectin bound to them from the serum. We found that, for the acetylated and deacetylated potato pectins, all or approximately half of the pectin molecules were bound to milk proteins at a pectin concentration of 0.25 or 1.0% (wt/wt), respectively. These results suggest that the presence of acetyl groups is a critical factor that determines how potato pectin molecules bind electrostatically to milk protein surfaces, form 3-dimensional structures there, and function as a stabilizer. The present results demonstrate that potato pectin can stabilize milk proteins at pH 5.5 and potentially enable the development of novel AMD products with improved functionality for casein-containing products with moderately acidic pH profiles.

SYNTHESIS OF ACETATE CELLULOSA FROM THE PALM OIL EMPTY FLOOR THROUGH THE REACTION OF ACTIVATION

Acetate cellulose is cellulose whose hydroxyl group is replaced by an acetyl group. Celluloseacetate has a high enough attractiveness because it is biodegradable so it is environmentally friendly. The purpose of this study is to increase the acetyl content of cellulose acetate by theacetylation reaction. This study uses 25 grams of empty fruit bunches to get cellulose, the delignification process is carried out for 30 minutes with NaOH solution, and the bleachingprocess for 1.5 hours with H2O2 solution. Next, as much as 5 grams of cellulose was carriedout by the acetylation process by adding glacial CH3COOH solution, anhydrous CH3COOHsolution with a ratio of 1:10, 1: 12.5 and 1:15 (w / v) and H2SO4 as a catalyst, withtemperature variations of 40oC, 55oC and 70oC. Next, an acetyl concentration was analyzedby titration, and substitution degree analysis was carried out. The best results obtained fromthe two analyzes will be carried out the Fourier Transform Infrared (FTIR) test and theScanning Electron Microscope (SEM) test. Acetyl content obtained was 8,152 - 24,58% andthe degree of substitution obtained was 0,3 - 1,2%.

Formation of Low Acetyl Content Cellulose Acetate Membrane for CO2/N2 Separation

Formation of Low Acetyl Content Cellulose Acetate Membrane for CO2/N2 Separation

Classification of Clinical Isolates of Klebsiella pneumoniae Based on Their in vitro Biofilm Forming Capabilities and Elucidation of the Biofilm Matrix Chemistry With Special Reference to the Protein Content.

Klebsiella pneumoniae is a human pathogen, capable of forming biofilms on abiotic and biotic surfaces. The limitations of the therapeutic options against Klebsiella pneumoniae is actually due to its innate capabilities to form biofilm and harboring determinants of multidrug resistance. We utilized a newer approach for classification of biofilm producing Klebsiella pneumoniae isolates and subsequently we evaluated the chemistry of its slime, more accurately its biofilm. We extracted and determined the amount of polysaccharides and proteins from representative bacterial biofilms. The spatial distribution of sugars and proteins were then investigated in the biofilm matrix using confocal laser scanning microscopy (CLSM). Thereafter, the extracted matrix components were subjected to sophisticated analysis incorporating Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, one-dimensional gel-based electrophoresis (SDS-PAGE), high performance liquid chromatography (HPLC), and MALDI MS/MS analysis. Besides, the quantification of its total proteins, total sugars, uronates, total acetyl content was also done. Results suggest sugars are not the only/major constituent of its biofilms. The proteins were harvested and subjected to SDS-PAGE which revealed various common and unique protein bands. The common band was excised and analyzed by HPLC. MALDI MS/MS results of this common protein band indicated the presence of different proteins within the biofilm. The 55 different proteins were identified including both cytosolic and membrane proteins. About 22 proteins were related to protein synthesis and processing while 15 proteins were identified related to virulence. Similarly, proteins related to energy and metabolism were 8 and those related to capsule and cell wall synthesis were 4. These results will improve our understanding of Klebsiella biofilm composition and will further help us design better strategies for controlling its biofilm such as techniques focused on weakening/targeting certain portions of the slime which is the most common building block of the biofilm matrix.

Pickering emulsions stabilized with cashew gum nanoparticles as indomethacin carrier.

Polysaccharide nanoparticles with potential to stabilize Pickering emulsions have been recently object of many research. Acetylated cashew gum with different degrees of substitution has been used in this work, in the pursuit of obtaining stable Pickering emulsions. Acetylated cashew gum was characterized by infrared and nuclear resonance spectroscopy. Effects of cashew gum derivative acetyl content, droplet size, ionic strength, zeta potential on emulsion properties were investigated. As a proof of concept, indomethacin was encapsulated in droplets and its release profile determined. Data obtained revealed droplet sizes in the range 269-312 nm, with unimodal size distribution and zeta potential values from -46 Mv to -48 Mv. Encapsulation efficiencies were in the range 26-52%, a steady release profile reached in 3 h, releasing maximal 75% IND.

A kinetic study of CO2 sorption improvement in the CA-CNTs mixed matrix membrane

Greenhouse emission notably carbon dioxide (CO2) in the atmosphere have been increasing significantly over the last century. Hence, there is a need to address this issue to minimize the adverse environmental effects. Membrane separation is one solution that could potentially help in this endeavour. Among the many types of membranes available, mixed matrix membrane (MMM) is the most promising with the potential to surpass the many deficiencies present in both inorganic and polymeric membranes. In this study, results confirmed that incorporation of functionalized CNTs increases CO2 permeance. Hence, the different loadings of MWCNTs-F were investigated to find the optimum gas separation performance. From this optimization study, excellent MMM performances in terms of CO2 permeance were shown in 0.1wt% loading of MWCNTs-F. This superior performance was attributed to a good homogeneous dispersion of MWCNTs-F in the CA matrix which consequently enlarged the free volumes between the polymer chains and improved the polymer nano particulate interface. Apart from this, a kinetic sorption study showed improvements in the CO2 solubility coefficient over previous related work at 14.9601 × 1013 cm3(STP)/cm4.cmHg. Hence, the usage of lower acetyl content is proven to be capable of increasing the CO2 solubility coefficient.

Biotransformation of plantain pseudostem fibres using local enzyme sources; analysis of their potential as commercial poultry feed

Plantain pseudo-stem fibres (PPS) were valorized in this study by subjecting to simultaneous saccharification and fermentation (SSF) and afterwards, their complex carbohydrates and monosaccharides, mycotoxins, protein qualities, and free radical scavenging potentials were compared to those of commercial poultry feeds (CPF). The SSF of PPS was achieved using digestive juice of the snail; Archachatina marginata, and yeast, while standard methods like HPLC-UV, HPLC-DAD, monosaccharides and mycotoxin kits, and UV-VIS spectrophotometry were used for analysis. The cellulose, hemicellulose, pectin, lignin, extractives, and acetyl contents of PPS were significantly (p < .05) reduced when subjected to SSF. Glucose (41.1%), galactose (11.2%), mannose (1.7%), and fucose (1.8%) contents of the SSF-PPS were higher than those of the PPS and CPF while CPF showed higher contents of arabinose (8.2%), fructose (18.3%), and rhamnose (1.7%). No mycotoxin was detected in the PPS, while all aflatoxins (B1, B2, G1, and G2), citrinin, fumonisin B1, and B2, ochratoxin A and B contents of SSF-PPS were equivalent to those for CPF. Patulin (5.52×10−4 µg/kg) and zearalenone (7.76×10−6 µg/kg) contents of the SSF-PPS were lower than those for CPF (1.50×10−3 µg/kg and 1.13×10−5 µg/kg respectively). The total amino acids (TAA), total non-essential and essential amino acids (TNEAA and TEAA), total basic and branched chain amino acids (TBAA and TBCAA) of the SSF-PPS were higher than those of the PPS and CPF while the free radical scavenging potentials of the SSF-PPS were mostly concentration dependent, and showed significantly higher ABTS, DPPH, Ferric, OH, lipid peroxide, and superoxide radical scavenging potentials than the standards used. This study has shown that the valorization of the agricultural residue using SSF, improves carbohydrate, protein, mycotoxins, and in-vitro antioxidant properties suitable enough for poultry feeding.

Partial removal of acetyl groups in konjac glucomannan significantly improved the rheological properties and texture of konjac glucomannan and κ-carrageenan blends

The main aim of the current study was to research the effect of the degree of konjac deacetylation on the rheological and textural properties of konjac glucomannan (KGM) and κ-carrageenan blends. A series of deacetylated konjac glucomannan (Da-KGM) with different degrees of deacetylation (0, 20.35%, 35.62%, 57.19%, and 74.01%) was prepared by a heterogeneous deacetylation method. The rheological and textural properties of mixed sols and gels of Da-KGM with different degrees of deacetylation and κ-carrageenan were determined. The results showed that the viscosities of mixed sols of Da-KGM and κ-carrageenan decreased with increasing degree of deacetylation. The partial removal of acetyl groups from konjac glucomannan could significantly improve the hardness and springiness of mixed gels of KGM and κ-carrageenan. Meanwhile, decreasing the acetyl content could decrease the syneresis of mixed gels. By regulating the deacetylation degree of konjac, gels with high gel strength could be prepared, which provides a new idea for the production of high-strength gelatin food.

Effect of Oxidation Level of High‐Amylose Corn Starch on Its Acetylation, Molecular Structure, and Functional Properties

The objective of this study is to determine the effect of oxidation level on susceptibility to acetylation, molecular structure, and functional properties of high‐amylose corn starch. High‐amylose corn starch is oxidized with sodium hypochlorite (equivalent 10, 20, 30 g Cl kg−1 starch) and acetylated with the acetic acid anhydride. Content of carboxyl, carbonyl, and acetyl groups; molecular size distribution, XRD spectra, specific surface, and morphology are determined in starches. Water‐binding capacity and solubility in water are also measured. Susceptibility of starch to the formation of stable organic radicals upon UV irradiation is detected with the EPR spectroscopy. The level of the oxidation of high‐amylose starch has a great impact on acetylation and on changes in starch structure. It is found that acetylation increases water binding capacity and water solubility of oxidized starches. High‐amylose corn starch exhibit strong susceptibility to radical formation which results from the fact that the liability of its structure is higher than that of normal and waxy ones. Modification processes prevented the destruction of starch against UV irradiation.

Brown-rot fungal degradation and de-acetylation of acetylated wood

Earlywood samples of unmodified and acetylated radiata pine were exposed to the brown-rot fungus Rhodonia placenta for 1, 2, 3 and 4 weeks for unmodified samples and 10, 16, 24 and 28 weeks for acetylated samples. Longer incubation periods were used for acetylated samples based on the hypothesis that given enough time under favourable conditions the fungus would eventually degrade the wood. After exposure, samples were weighed and chemically characterized by ATR-FTIR analysis, acetyl content by saponification, and hydroxyl (OH) accessibility by deuterium exchange. Longer incubation times for acetylated samples led to comparable levels of mass loss between unmodified and acetylated wood. Initial brown-rot decay in acetylated wood exhibited a different trend compared to unmodified wood, with an increased OH accessibility and a significant reduction in acetyl content. This was followed by a stable, low OH accessibility and plateau in acetyl content above 10% mass loss in acetylated wood. In unmodified wood, the OH accessibility was nearly constant throughout decay, while the initially low acetyl content decreased linearly with mass loss. ATR-FTIR analysis confirmed the differences in acetyl removal between unmodified and acetylated wood. Wood-water relations before and after brown-rot decay were determined with low-field nuclear magnetic resonance (LFNMR) relaxometry on water saturated samples. For the decayed acetylated wood, the behaviour of the water corresponded well with de-acetylation observed by chemical characterization. The results show that after removal of acetyl groups, degradation of acetylated wood by R. placenta occurred at a similar rate to that of unmodified wood.

PREPARATION AND CHARACTERISATION OF ACETYLATED WHEAT STARCH SUPPORTING FOR DIABETES TREATMENT

Background: The purpose of the study was to prepare acetylated wheat starches which have amylase hydrolysis resistant capacity to use as functional food supporting for diabetes treatment. Method: Acetate wheat starches were prepared by acetylation reaction of native wheat starch with different mole ratios of acetic anhydride. These starches were determined for the physicochemical properties by 1H-NMR, SEM, X-ray, DSC, solubility and swelling capacity, the resistant capacity by amylase hydrolysis in-vitro. Results: Acetate wheat starches were prepared successfully with the increase in acetyl content and degree of substitution corresponding with the increase of anhydride acetic, which resulted in the change of physicochemical properties of the wheat starches, including constitution, solubility, swelling capacity and contributed to the increase in resistant starch content in the acetate wheat starches. The AC150-9 containing 2.42% acetyl with degree of substitution 0,094 and resistant starch 32,11% is acceptable by FDA guideline about food safety. Conclusion: Acetate wheat starches contain low rate of digestive starch, while containing a higher proportion of resistant starch than natural wheat starch, possessing a high resistance to amylase activities. Thus, it is hope that this kind of starch to control the rapid increase of postprandual blood glucose response for diabetes treatments effectively. Key words: Acetate wheat starch, substitution, DS, RS, amylase

Alternative chemo-enzymatic treatment for homogeneous and heterogeneous acetylation of wood fibers

A new chemo-enzymatic treatment is proposed to produce cellulosic fibers suitable for heterogeneous- or homogeneous-phase acetylation. The procedure included enzymatic (laccase–violuric acid) lignin removal from the precursor fibers (unbleached sulfite pulp) followed by hydrogen peroxide treatment. An optional intermediate stage included partial hydrolysis (endoglucanase) to increase fiber reactivity. The obtained “biobleached” fibers were acetylated in the heterogeneous phase with acetic anhydride in nonpolar solvents, yielding various acetyl group contents, depending on the severity of the reaction. The degree of acetylation was highly sensitive to the treatment conditions, mainly the acetic anhydride activity in the system. The results were compared to those obtained after acetylation of commercial, dissolving-grade fibers, used as reference. The effect of the inherent nature of the fibers tested were elucidated as far as hemicellulose content, fiber length, fine content and crystallinity. Acetyl group content of up to 24% were determined after heterogeneous reaction with the chemoenzymatic fibers. The substitution of hydroxyl groups by acetyl moieties resulted in a lower hydrophilicity, as assessed by measurement of the water contact angle. Homogeneous acetylation of the chemo-enzymatic and reference fibers resulted in relatively similar acetyl group content (up to 36 and 33%, respectively). These samples were soluble in acetone and produced transparent films (via solvent casting), with enhanced dry strength and lower hydrophilicity. Overall, it is concluded that the proposed chemo-enzymatic treatment is a feasible alternative for the production of fibers that are suitable for efficient acetylation.

Rheological behaviour of acetylated pectins from cactus pear fruits (Opuntia albicarpa and O. matudae)

Acetylated-low methoxyl pectins were isolated from sweet prickly-pear (Opuntia albicarpa) and ‘xoconostle’ or acidic prickly-pear (O. matudae), by sequential extraction with water in presence of ethylenediaminetetraacetic acid as sequestering agent. The extraction protocol resulted in the isolation of pectins of good enough purity as evidenced by their high galacturonic acid contents (65.23 and 75.72% w/w, for sweet prickly-pear pectin (PP) and xoconostle pectin (XP), respectively). Both pectins had an important protein content (10.82 and 2.58% for PP and XP, respectively) and they can be described as acetylated-low methoxyl pectins. Degree of methoxylation (DM) and degree of acetylation (DA) values for PP were 26.83 and 21.83%, respectively. XP showed DM and DA values of 45.62% and 4.94%, respectively. Weight-average molecular weight (Mw) values of 204.08 and 161.73 kDa were determined for PP and XP, respectively. Pectin aqueous dispersions showed a non-Newtonian rheological behaviour which had good fitting to the Cross equation. The viscoelastic behaviour of 1%-pectin-calcium systems exhibited a predominantly solid-like character, the presence of 1 mM CaCl2 was enough to the formation of soft gels, the further increase of Ca2+ ions (3 and 5 mM) yielded the formation of soft and elastic gels. The viscoelastic solid behaviour of PP gels was more dominant than that of XP gels. The high content of acetyl groups did not have negative effect on the gel formation ability of both, PP and XP.

Studies on Isolation, Modification, Characterization and Evaluation of Some Physicochemical Parameters of Potato Starch

Objectives: To isolate and modify starch using new and non-commonly used commercially available, cost-effective reagents and study the changes in functionality and physicochemical properties. Methods/Statistical Analysis: An outline and modification of the method: Addition of 100 mL of a 500 mL solution of 3.5 % hypochlorite (household bleach commonly known as hypo) in 2 L of water at interval of 1 min during grinding. Hypo substituted sodium metabisulphite, prevented browning and enhanced rasping and acted as bleach. Mucilage obtained by the modified method was nonsticky to starch cake. FT-IR results confirmed the direct formation of oxidized starch. Findings: Acetyl content (0.01-0.89 %) and DS (0.011-0.2) obtained by the modified method was in agreement with the approved DS by the Food and Drug Administration for food use. Proximate results showed that the isolated starch was rich in mineral content, fibre, fat and energy. Thermoplasticity of high temperature mercerized starch was revealed by SEM images. These properties will influence their use in composites and other applications where strength needs to be improved as documented. Mercerized starches as flocculants in water cleaning as ion changers or retention agents in the paper industry. The C=O absorption bands were observed at 1634, 1650, 1647 and 1646 cm-1 for mercerized starch. Bands observed at 1640, 1641, 1640, 1640 and 1642 cm-1 and 2932, 2926, 2920 and 2929 cm-1 and 1358, 1389, and 1385 cm-1 are assigned CO, C-H of methylene and -CH2 stretching vibrations in ester group due to acetylation. Results of these findings showed the application of hypo and vinegar for isolation and acetylation of starch respectively. Application/Improvements: The feasibility of the modified method for starch isolation and modification using readily available, cost effective and eco-friendly chemicals for obtainment of food and pharmaceutical grade starch. Keywords: Characterization, Modification, Potato, Starch, FT-IR, SEM

Xanthan gum production from acid hydrolyzed broomcorn stem as a sole carbon source by Xanthomonas campestris.

Xanthan gum is an exo-polysaccharide industrially produced by fermentation using simple sugars. In this study, broomcorn stem was introduced as a low-cost- and widely available carbon source for xanthan gum fermentation. Broomcorn stem was hydrolyzed using sulphuric acid to liberate reducing sugar which was then used as a carbon source for biosynthesis of xanthan gum by Xanthomonas campesteris. Effects of hydrolysis time (15, 30, 45 and 60min), sulphuric acid concentration (2, 4, 6 and 8% v/v) and solid loading (3, 4, 5 and 6% w/v) on the yield of reducing sugar and consequent xanthan production were investigated. Maximum reducing sugar yield (55.2%) and xanthan concentration (8.9g/L) were obtained from hydrolysis of 4% (w/v) broomcorn stem with 6% (v/v) sulphuric acid for 45min. The fermentation product was identified and confirmed as xanthan gum using Fourier transform infrared spectroscopy analysis. Thermogrvimetric analysis showed that thermal stability of synthesized xanthan gum was similar to those reported inprevious studies. The molecular weight of the produced xanthan (2.23 × 106g/mol) was determined from the intrinsic viscosity. The pyruvate and acetyl contents in xanthan gum were 4.21 and 5.04%, respectively. The chemical composition results indicated that this biopolymer contained glucose, mannose and glucoronic acid with molecular ratio of 1.8:1.5:1.0. The kinetics of batch fermentation was also investigated. The kinetic parameters of the model were determined by fermentation results and evaluated. The results of this study are noteworthy for the sustainable xanthan gum production from low-value agricultural waste.

Effects of conventional and microwave pretreatment acetylation on structural and physicochemical properties of wheat starch

SummaryThe changes in structural and physicochemical properties of wheat starch after conventional and microwave pretreatment acetylation process were investigated and compared. The microscopy analysis showed that the microwave pretreatment acetylation significantly influenced the surface and interior structure of starch granules compared with the conventional acetylation. The microwave pretreated and untreated starch granules retained the A‐type crystalline structure with decreased relative crystallinity after acetylation. The microwave pretreated starch showed higher degree of substitution, acetyl content, and gelatinisation and pasting temperatures than those of the untreated starch after acetylation under the same conditions. However, the microwave pretreated starch showed lower gelatinisation enthalpy, light transmittance, and peak viscosity compared with the untreated starch after acetylation. Furthermore, water solubility and swelling power of the microwave pretreated and untreated starch increased after acetylation. Generally, the microwave pretreatment acetylation significantly modified structural and physicochemical properties of wheat starch compared with single acetylation process. Therefore, a combination of microwave pretreatment with acetylation can be suggested for modification of wheat starch to promote its applications in the food and nonfood industries.