Acid hydrolysis

This work evaluates the use of sugarcane bagasse (SCB) as a source of cellulose to obtain whiskers. These fibers were extracted after SCB underwent alkaline peroxide pre-treatment followed by acid hydrolysis at 45 • C. The influence of extraction time (30 and 75 min) on the properties of the nanofibers was investigated. Sugarcane bagasse whiskers (SCBW) were analyzed by transmission electron microscopy (TEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA) in air atmosphere. The results showed that SCB could be used as source to obtain cellulose whiskers and they had needle-like structures with an average length (L) of 255 ± 55 nm and diameter (D) of 4 ± 2 nm, giving an aspect ratio (L/D) around 64. More drastic hydrolysis conditions (75 min) resulted in less thermally stable whiskers and caused some damage on the crystal structure of the cellulose as observed by XRD analysis.

Six pecan cultivars were analyzed for their antioxidant capacity (AC), total phenolics (TP), condensed tannin (CT), HPLC phenolic profile, tocopherol and fatty acid composition. Kernels which included the outer brown testa or pellicle, and shells which is the hard cover that surrounds the kernel, were evaluated for each cultivar. Strong correlations were found in kernels between AC and TP for both DPPH (r 2 = 0.98) and AC ORAC (r 2 = 0.75) antioxidant assays. AC ORAC values ranged from 372 to 817 lmol trolox equivalents/g defatted kernel, corresponding to Desirable and Kanza cultivars, respectively. CT ranged from 23 to 47 mg catechin equivalents/g defatted kernel and TP from 62 to 106 mg of chlorogenic acid equivalents/g defatted kernel. After a consecutive basic-acid hydrolysis, gallic acid, ellagic acid, catechin and epicatechin were identified by HPLC. The TP, AC and CT were 6, 4.5 and 18 times higher, respectively, for shells compared to kernels. The presence of phenolic compounds with high antioxidant capacity in kernels and shells indicates pecans can be considered an important dietary source of antioxidants.

Autohydrolysis and dilute-acid hydrolysis were used as pretreatment methods to enhance the enzymatic digestibility of cellulose in two different lignocellulosic substrates, a softwood mixture and an agricultural residue of almond shells. The changes in the chemical composition of the softwood mixture during dilute-acid pretreatment were studied, and the results were grouped by using a severity parameter, KR OH , which was derived from the kinetics of hemicellulose solubilization. The average degree of polymerization of the cellulose retained in the pretreated substrate, DP v , was investigated and its trend compared with that of almond shells. Cellulose DP v decreased for both the substrates from a value of 700 for the untreated lignocellulosic to around 200, which corresponds to the leveling-off degree of polymerization, as there is no significant variation in DP v when severity increases. Glucose yields after enzymatic saccharification of the pretreated substrates turned out to be higher for almond shells than for the softwood mixture, which had a very low susceptibility to enzymatic hydrolysis throughout the spectrum of experimental conditions investigated. At KR OH ) 15 000, the glucose yield for the softwood mixture is 44% of the potential fraction present in the pretreated pulp, while for almond shells the maximum yield surpasses 97% for KR OH ) 3. The different behavior between these lignocellulosic species is not caused by different degrees of cellulose depolymerization nor by the removal of different amounts of carbohydrates during pretreatments in equivalent conditions.

Moringa oleifera is an important multipurpose tropical tree under-recognized for its nutritional and medicinal properties. Leaves of moringa collected from sub-Sahara Africa were analyzed for phenolic components by HPLC-UV-MS. Twelve flavonoids were identified, including quercetin and kaempferol glucosides and glucoside malonates as major constituents. To facilitate quantitative analysis, acid hydrolysis during extraction of moringa samples was employed to convert the conjugates into their respective flavonoid aglycones, allowing accurate quantitation of total flavonoids as aglycones. Validation of the method demonstrated recoveries ranging from 92.6% to 107.5% for the two analytes. Using this method, total flavonoids from moringa collected from Ghana, Senegal and Zambia were determined and their content ranged from 0.18% to 1.64% (g/dry weight) across the respective environment or country of production and by variety. Moringa was found to exhibit anti-inflammatory activity of constituents-rich varieties. As flavonoid malonates are among the major constituents in the original plant material, a study examining thermal stability of flavonoid malonyl derivatives showed that these compounds were not thermally stable and easily cleaved to yield their respective flavonoid glycosides.

The underlying mechanisms governing nonenzymatic pectin and pectate degradation during thermal treatment have not yet been fully elucidated. This study determined the extent of nonenzymatic degradation due to -elimination, acid hydrolysis, and demethylation during prolonged heating of citrus pectins and its influence on physicochemical properties. Solutions of citrus pectins, buffered from pH 4.0 to 8.5, were heated at 75, 85, 95, and 110°C for 0-300 min. Evolution of methanol and formation of reducing groups and unsaturated uronides were monitored during heating. Molecular weight and viscosity changes were determined through size exclusion chromatography and capillary viscometry, respectively. Results showed that at pH 4.5, the activation energies of acid hydrolysis, -elimination, and demethylation are 95, 136, and 98 kJ/mol, respectively. This means that at this pH, acid hydrolysis occurs more rapidly than -elimination. Furthermore, the rate of acid hydrolysis is diminished by higher levels of methyl esterification. Also, citrus pectin (93% esterified) degrades primarily via -elimination even under acidic conditions. Acid hydrolysis and -elimination caused significant reduction in relative viscosity and molecular weight.

Pectin is a functional technology product by her rheological characteristics. In 2010 in Colombia, there were imported approximately 195 tons and its demand is increasing. The main goal of this research was to extract and characterize the pectin from ripe sugar mango peel. The isolation of pectin material was accomplished by acid hydrolysis, with hydrochloric acid to 0.5 N and ethyl alcohol to 96 % for precipitation and purification. For the extraction of pectin factorial arrangement 32 was used where the two factors evaluated were: pH and temperature, which took the levels 1, 2, 3 and 80, 90, 100 respectively, in a constant time of 60 minutes. There were 27 experimental units equivalent to 550 g of ripe, dry and ground sugar mango peel. The results were evaluated and it was stated that ideal variables (pH 1 and temperature 100 ºC) allow to extract major quantity of pectin, bringing a performance of 15.257±0.04%. The obtained pectin presented the following characteristics: humidity content (4.510 ± 0.80%), ashes content (1.351± 0.07%), alkalinity of the ashes (1.711±1.13%), free acidity (0.859±0.01 mEq free / g carboxyl), equivalent weight (2326.420±54.11 mg / mEq), methoxyl (11,801 ±0.03%), degree of esterification (81.688±024%), anhydrous acid content (82.380±0.17%) and the analysis by infrared spectrophotometry, showed the peaks of functional groups, typical of the obtained pectin and its similarity opposite to a standard pectin. The material studied is a potential source of quality pectin.

The dilute acid hydrolysis of grass and cellulose with phosphoric acid was undertaken in a microwave reactor system. The experimental data and reaction kinetic analysis indicate that this is a potential process for cellulose and hemi-cellulose hydrolysis, due to a rapid hydrolysis reaction at moderate temperatures. The optimum conditions for grass hydrolysis were found to be 2.5% phosphoric acid at a temperature of 1758C. It was found that sugar degradation occurred at acid concentrations greater than 2.5% (v/v) and temperatures greater than 1758C. In a further series of experiments, the kinetics of dilute acid hydrolysis of cellulose was investigated varying phosphoric acid concentration and reaction temperatures. The experimental data indicate that the use of microwave technology can successfully facilitate dilute acid hydrolysis of cellulose allowing high yields of glucose in short reaction times. The optimum conditions gave a yield of 90% glucose. A pseudo-homogeneous consecutive first order reaction was assumed and the reaction rate constants were calculated as: k 1 ¼ 0.0813 s 21 ; k 2 ¼ 0.0075 s 21 , which compare favourably with reaction rate constants found in conventional non-microwave reaction systems. The kinetic analysis would indicate that the primary advantages of employing microwave heating were to: achieve a high rate constant at moderate temperatures: and to prevent 'hot spot' formation within the reactor, which would have cause localised degradation of glucose.

The dilute acid hydrolysis of grass and cellulose with phosphoric acid was undertaken in a microwave reactor system. The experimental data and reaction kinetic analysis indicate that this is a potential process for cellulose and hemi-cellulose hydrolysis, due to a rapid hydrolysis reaction at moderate temperatures. The optimum conditions for grass hydrolysis were found to be 2.5% phosphoric acid at a temperature of 1758C. It was found that sugar degradation occurred at acid concentrations greater than 2.5% (v/v) and temperatures greater than 1758C. In a further series of experiments, the kinetics of dilute acid hydrolysis of cellulose was investigated varying phosphoric acid concentration and reaction temperatures. The experimental data indicate that the use of microwave technology can successfully facilitate dilute acid hydrolysis of cellulose allowing high yields of glucose in short reaction times. The optimum conditions gave a yield of 90% glucose. A pseudo-homogeneous consecutive first order reaction was assumed and the reaction rate constants were calculated as: k 1 ¼ 0.0813 s 21 ; k 2 ¼ 0.0075 s 21 , which compare favourably with reaction rate constants found in conventional non-microwave reaction systems. The kinetic analysis would indicate that the primary advantages of employing microwave heating were to: achieve a high rate constant at moderate temperatures: and to prevent 'hot spot' formation within the reactor, which would have cause localised degradation of glucose.

Microfibrillated cellulose nanofibers (MFC) provide strong reinforcement in polymer nanocomposites. In the present study, cellulosic wood fiber pulps are treated by endoglucanases or acid hydrolysis in combination with mechanical shearing in order to disintegrate MFC from the wood fiber cell wall. After successful disintegration, the MFC nanofibers were studied by atomic force microscopy (AFM). Enzyme-treatment was found to facilitate disintegration, and the MFC nanofibers produced also showed higher average molar mass and larger aspect ratio than nanofibers resulting from acidic pretreatment.

Cellulose was extracted at a yield of 59.8% from jute fibres based on the formic acid/ peroxyformic acid process at an atmospheric pressure. The amounts of dissolved lignin and hemicelluloses were determined in the spent liquor. The results showed that the spent liquor contained 10.6% total sugars and 10.9% lignin (based on jute). Microcrystalline cellulose (MCC) was further prepared from the jute cellulose based on the acid hydrolysis technique. A very high yield, 48-52.8% (based on the jute raw material) was obtained. The acid hydrolysate of cellulose contained 2.7% glucose and 0.2% xylose. The MCC samples obtained from two different conditions, one at a low acidity and the other at a high acidity, were characterized by means of Thermo Gravimetric Analysis, Fourier Transform Infrared, X-ray detraction, Scanning Electron Micrograph, and Transmission Electron Micrograph techniques.

The present work describes the validation of an easy, fast and efficient precolumn derivatization method for the quantification of oligosides, mannose and galactose obtained by degradation of galactomannans. This work combines an acid hydrolysis and an enzymatic degradation of natural galactomannans with the quantification of released residues by reversed-phase HPLC-UV, the most usual HPLC system in laboratories. In case of enzymatic degradation, mannotetraose has been detected and quantified for the first time, and an application to the evaluation of the galactosyl distribution in galactomannans is proposed. After an acidic hydrolysis, this method also allowed to obtain the mannose/galactose (M/G) ratio.

The feasibility of ethanol production from the construction and demolition (C&D) wood waste acid hydrolysates was investigated. The chemical compositions of the classified C&D wood waste were analyzed. Concentrated sulfuric acid hydrolysis was used to obtain the saccharide hydrolysates and the inhibitors in the hydrolysates were also analyzed. The C&D wood waste composed of lumber, plywood, particleboard, and medium density fiberboard (MDF) had polysaccharide (cellulose, xylan, and glucomannan) fractions of 60.7-67.9%. The sugar composition (glucose, xylose, and mannose) of the C&D wood wastes varied according to the type of wood. The additives used in the wood processing did not appear to be released into the saccharide solution under acid hydrolysis. Although some fermentation inhibitors were detected in the hydrolysates, they did not affect the ethanol production by Pichia stipitis. The hexose sugar-based ethanol yield and ethanol yield efficiency were 0.42-0.46 g ethanol/g substrate and 84.7-90.7%, respectively. Therefore, the C&D wood wastes dumped in landfill sites could be used as a raw material feedstock for the production of bioethanol.

A gas chromatography-mass spectrometry (GC-MS) method for the simultaneous determination of phenol (PHE), hydroquinone (HQ) and catechol (CAT) in urine was developed and validated. The method was based on the acidic hydrolysis of conjugated phenolic compounds and further extraction of analytes using solid-phase microextraction (SPME). Analytes were extracted by submersing the polar polyacrylate coated fiber (85 lm) into urine (adjusted to pH 3.0 with glacial acetic acid) for 20 min with magnetic stirring. The extracted compounds on the fiber were exposed to hexamethyldisilazane reagent in the vapor phase for 20 min to yield the corresponding trimethysililylated derivates. This on-fiber derivatization procedure allowed the formation of more amenable compounds for GC analysis, without adversely affecting the lifetime of the fiber. The MS was operated in the selected ion monitoring mode (SIM). The limits of detection were 0.3 lg mL )1 for PHE, 0.15 lg mL )1 for HQ and 0.02 lg mL )1 for CAT. Inter and intra-assay precisions were also verified (coefficient of variation < 8%) with the use of deuterated internal standards. This method of GC-MS analysis can be readily utilized to monitor PHE and its metabolites (HQ and CAT) in urine samples.

Paramyxoviruses are the leading cause of respiratory disease in children. Several paramyxoviruses possess a surface glycoprotein, the hemagglutinin-neuraminidase (HN), that is involved in attachment to sialic acid receptors, promotion of fusion, and removal of sialic acid from infected cells and progeny virions. Previously we showed that Newcastle disease virus (NDV) HN contained a pliable sialic acid recognition site that could take two states, a binding state and a catalytic state. Here we present evidence for a second sialic acid binding site at the dimer interface of HN and present a model for its involvement in cell fusion. Three different crystal forms of NDV HN now reveal identical tetrameric arrangements of HN monomers, perhaps indicative of the tetramer association found on the viral surface.

Ethanol is considered the most potential next generation automotive fuel because it is carbon-neutral and could be produced from renewable resources like lignocellulosic biomass. There are some technological barriers such as pretreatment, saccharification of cellulose and hemicellulose matrix, and simultaneous fermentation of hexose and pentose sugars which needs to be addressed for efficient conversion of lignocellulosic biomass to bioethanol. This paper reviews the various process options and kinetic models adopted towards resolving the technological challenges to develop a low-cost commercial process.

Atomic force microscopy images of sectioned native corn starch granules show evidence of the well-known radial organisation of the starch macromolecules, with the less-ordered hilum region near to the centre. Native granules show blocks 400 -500 nm in size that span the growth rings. Lintnerised starch granules, where a mild acid hydrolysis has been used to remove the amorphous and less crystalline parts of the granule, clearly show smaller 'blocklets' within the rings approximately 10 -30 nm in size. This level of organisation within the growth rings corresponds to the blocklet or superhelix structures that have been proposed in the literature for the association or clustering of amylopectin helices. Mechanical property imaging techniques have provided enhanced contrast to view this morphology, and shown the deformability of the starch structure under contact mode imaging conditions. (A.A. Baker), [email protected] (M.J. Miles).

A simple method for the preparation of homochiral ring-substituted 1-aryl-2-aminopropanones 2 ('cathinones') is described, involving initial Friedel-Crafts acylation of aromatics with (S)-or (R)-N-trifluoroacetylalanyl chloride, followed by acid hydrolysis of the intermediate trifluoroacetamido intermediates 1, for which X-ray diffraction analysis confirmed the structures.

Office of Basic Science. Funding was approved in July of 1999 and received by participating Mississippi institutions by 2000. The project was funded via two 3-year phases of operation (the second phase was awarded based on the high merits observed from the first 3-year phase), with funding ending in 2007. The mission of the Consortium was to promote the utilization of biomass, both cultured and waste derived, for the production of commodity and specialty chemicals. These scientific efforts, although generally basic in nature, are key to the development of future industries within the Southeastern United States. In this proposal, the majority of the efforts performed under the DOE EPSCoR funding were focused primarily toward the production of ethanol from lignocellulosic feedstocks and biogas from waste products. However, some of the individual projects within this program investigated the production of other products from biomass feeds (i.e. acetic acid and biogas) along with materials to facilitate the more efficient production of chemicals from biomass.

This study was performed to identify and characterize the radiometabolites of the serotonin 5-HT 2A receptor ligand [ 18 F]altanserin in supporting quantification of the target receptors by positron emission tomography. In analogy to its analog ketanserin, we postulated 4-(4-fluorobenzoyl)piperidine (FBP) and altanserinol for the previously observed two polar radiometabolites, corresponding to dealkylation at the piperidine nitrogen and reduction at the ketone, respectively. To test this hypothesis and characterize the in vivo and in vitro behavior of the radiometabolites, we synthesized nonradioactive authentic compounds altanserinol, 1

The overall aim of this work was to establish the optimum conditions for acid hydrolysis of hemicellulosic biomass in the form of potato peel. The hydrolysis reaction was undertaken in a 1l high pressure pilot batch reactor using dilute phosphoric acid. Analysis of the decomposition rate of hemicellulosic biomass (namely Cellulose, Hemicellulose and lignin) was undertaken using HPLC of the reaction products namely, 5 and 6 carbon sugars. Process parameters investigated included, reactor temperature (from 135 • C to 200 • C) and acid concentration (from 2.5% (w/w) to 10% (w/w)). Analysis of the reactor products indicated that high conversion of cellulose to glucose was apparent although arabinose conversion was quite low due to thermally un-stability. However, an overall sugar yield is 82.5% was achieved under optimum conditions. This optimum yield was obtained at 135 • C and 10% (w/w) acid concentration. 55.2 g sugar/100 g dry potato peel is produced after a time of 8 min. The work indicates that the use of potato peel may be a feasible option as a feed material for the production of sugars for biofuel synthesis, due its low cost and high sugar yields.

Selective separation of citric acid and process optimization for its recovery from fermented broth through precipitation and acid hydrolysis were tried. A mathematical model has been proposed for yield. The experimental values are in good agreement with predicted values; the correlation coefficient was found to 0.9198.

The Policy Research Working Paper Series disseminates the findings of work in progress to encourage the exchange of ideas about development issues. An objective of the series is to get the findings out quickly, even if the presentations are less than fully polished. The papers carry the names of the authors and should be cited accordingly. The findings, interpretations, and conclusions expressed in this paper are entirely those of the authors. They do not necessarily represent the views of the International Bank for Reconstruction and Development/World Bank and its affiliated organizations, or those of the Executive Directors of the World Bank or the governments they represent.

An integration process to produce biohydrogen by rice straw hydrolysate and anaerobic fermentation was proposed in this study. The rice straw was used as the raw material to generate reducing sugar (RS) for the anaerobic fermentation to produce biohydrogen.

Municipal and industrial wastewater treatment plants produce large amounts of sludge, containing organic and mineral components and being mechanically dewatered to e.g. 20-25% DS in centrifuges. Both the reduction of the amount of sludge produced and improving its dewaterability are hence of paramount importance. Hot acid hydrolysis can meet these objectives. The current paper describes the results of detailed investigations with respect to acid hydrolysis of thickened sludge (5-6% DS content). A comparison with traditional thermal hydrolysis is also included. As a result of the experimental investigations, it can be concluded that hot acid hydrolysis is efficient in both reducing the residual sludge amounts and improving the dewaterability. Under the proposed optimum conditions it is found that (i) the amount of hydrolysed DS is approximately 70% lower than the initial untreated amount, (ii) the DS-solid content of the dewatered cake is increased from 22.5% (initial untreated) to at least twice this value, (iii) the rate of mechanical dewatering is not significantly affected. The preferential release of ODS into the water phase, and the increased BOD/COD-ratio through hydrolysis, turn this recycle water phase into a possible carbon-source for nitrification/denitrification. Heavy metals and phosphates are also released in the water phase, and can be subsequently precipitated.

A 96-well plate method was developed for analysis of total hexosamine content in biological samples. Four hexosamine monomer derivatives-glucosamine hydrochloride, glucosamine sulfate, galactosamine hydrochloride, and mannosamine hydrochloride-were examined for the linearity of their spectra in the concentration range specified in the assay. The hexosamine concentration analysis range was linear from 0.1 to 1 mM. The quantification of hexosamines from chitin and chitosan upon acid hydrolysis was also tested. Accurate quantification of glucosamine content in chitin and chitosan with different molecular sizes and degrees of acetylation was demonstrated using the new method.

Taro corms were cooked in four different mediums (water, tamarind solution, lemon solution, or steam) during 25 min. Changes in hardness, soluble sugars, soluble proteins, degree of gelatinisation (iodine index), degree of cell separation (VICS), resistant starch, total oxalate, absorbance at 280 nm (A 280) and 450 nm (A 450) were evaluated. The results showed that irrespective of the cooking medium, the hardness, soluble proteins, and resistant starch significantly decreased during cooking while A 280 , A 420 , iodine index, VICS and soluble sugars significantly increased. A significant correlation was observed between the hardness and the iodine value, resistant starch, soluble sugars and VICS, suggesting multiple mechanisms involved in the softening of taro corms during cooking. It was observed that steam cooking of the slices induces the highest softening while boiling in water induces the lowest softening of the corms. However cooking in tamarind and lemon solutions induced a bitter and acid taste to the corms. While no consistent change was observed during steaming, significant reduction was observed in the oxalate content during boiling probably due to leaching in boiling solutions and acid hydrolysis.

Terpenes contribute to some white wines aroma, especially these produced from Muscat grapes and others aromatic ones of high terpene contents (Gewürtztramminer, Traminer, Huxel, Sylvaner). Terpenes are present in wine in free and bound (in a form of glycosides) forms. Analyses of bound terpenes are usually performed using solid phase extraction after hydrolysis of glycosides. A new method for determination of terpenes from wine, focused on determination of terpenes released after acidic hydrolysis, based on solid phase extraction (SPE) followed by solid phase microextraction (SPME) was developed. Non-polar (free) and polar (bound terpenes) fractions were separated on 500 mg C18 cartridges. Bound terpenes were sampled using SPME immediately after acidic hydrolysis in non-equilibrium conditions. Application of combined SPE-SPME approach allowed quantification of selected terpenes in lower concentrations than in SPE approach and added a selectivity to the method, which enabled detection of compounds nondetectable in SPE extracts. Results obtained by SPE and SPE-SPME approach were correlated for free terpenes and those released after acid hydrolysis 20 white wines obtained from different grape varieties (R 2 = 0.923). Although developed for wine terpenes analysis, SPE followed by SPME approach has a great potential in analysis of other bound wine flavor compounds, especially those potent odorants present in trace amounts.

The synthesis and characterization of new molecular sieves of the MCM-41 type are presented in this study. Samples were obtained from the alkoxides of Si, Ti and Al and different long-chain amine and alkylammonium salts surfactants, by the sol-gel method, through moderate agitation at room temperature. The reactions were conducted in two steps, acid hydrolysis (pH=2) and alkaline condensation (pH=10), both taking about 90min. The synthesized crystals were characterized using infrared spectroscopy, thermogravimetry and X-Ray diffraction. Pore diameters and surface areas were measured by N 2 adsorption at 77K. Catalytic tests were conducted for anthracene oxidation using different oxidants (H 2 O 2 , alkylhydroperoxide) and organic solvents (benzene, tetrahydrofuran).

A water-soluble polysaccharide of an edible mushroom Calocybe indica var. APK2 showed immunoenhancing (macrophage, splenocyte, thymocyte, and bone marrow activation) and cytotoxic activity toward HeLa cell lines and found to consist of d-glucose, d-galactose, and l-fucose in a molar ratio of nearly 3:1:1. On the basis of acid hydrolysis, methylation analysis, and NMR studies (1H, 13C, DEPT-135, TOCSY, DQF–COSY, NOESY,

A method was developed for estimating the content in foods of the emulsifying additive E473, sucrose esters of fatty acids. The analytical approach taken to estimate the complex mixtures that comprise this additive involved, selective solvent extraction of the intact ...

Seven lignin fractions were isolated from dewaxed sweet sorghum stem and their physicochemical features were investigated. The dewaxed sweet sorghum stem was extracted sequentially with hot water, 50% dioxane and dimethyl sulfoxide (DMSO), and various concentrations of NaOH. The treatments resulted in dissolution of 0.5, 0.7, 0.2, 1.3, 1.6, 0.8, and 0.5% lignin, corresponding to release of 8.9, 12.5, 3.6, 23.2, 28.6, 14.3, and 8.9% of the total solubilized lignin, respectively. The seven lignin fractions were comparatively characterized by chemical composition, structural features, and molecular weights using alkaline nitrobenzene oxidation, acid hydrolysis, UV, FT-IR, 1 H and 13 C NMR spectroscopy, and GPC. The purity of the lignin fractions isolated by 50% dioxane and alkali was higher than that of the lignin preparations obtained by hot water and DMSO, in which the content of associated polysaccharides in the former lignin fractions (0.16-2.12%) was much lower than those of the latter lignin preparations (10.39 and 37.03%). It was found that the seven lignin fractions contained substantial amounts of non-condensed guaiacyl and syringyl units with fewer p-hydroxyphenyl units, and had weight-average molecular weights between 1270 and 3590 g mol −1. No substantial differences in the main structural features between the lignin preparations isolated with 50% dioxane and alkali were found and these treatments did not result in significant changes in lignin composition and its structure.

A flavonoid aglycone survey was carried out on 46 taxa of the family Dipterocarpaceae belonging to the genera Cotylelobium, Dipterocarpus, Hopea, Shorea, Stemonoporus, Vateria and Vatica. After acid hydrolysis the main aglycones found were the flavonols quercetin and kaempferol, and the flavone apigenin. The flavone luteolin was present in all the species of the genus Shorea and was absent in the rest of the species of the family, giving a chemotaxonomic significance to its presence. The flavonol myricetin was detected in only three species of Shorea, S. affinis, S. trapezifolia, and S. gardneri. Proanthocyanidins were only found in 13 species of Shorea and two species of Dipterocarpus. These two genera can be regarded as the most primitive with respect to the flavonoid patterns and the other five genera have more advanced patterns, recognizing Stemonoporus as the most advanced. The aglycone results do not completely agree with the existing classifications, and suggests the need for a revision of the species and sectional levels in the family Dipterocarpaceae in Sri Lanka.

The main toxic compound found in false morel (Gyromitra esculenta) is acetaldehyde-N-methyl-N-formylhydrazone (gyromitrin). This paper describes a method of determining the total hydrazones content based on acid hydrolysis of gyromitrin and other related hydrazones in air-dried false morel followed by derivatisation of methylhydrazine with pentafluorobenzoyl chloride. The derivative, tris-pentafluorobenzoyl methylhydrazine (tris-PFB-MH) is analyzed by gas chromatography–mass spectrometry. The overall precision

a b s t r a c t POSS-modified nanofibrillated cellulose (PNFC) was used as a carbon source in intumescing flame retardants (IFRs) for melt-blended poly(lactic acid) (PLA) composites. The POSS moeities were found to inhibit reactions between ammonium polyphosphate (APP) and cellulose during extrusion. Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) indicated this was due to cross-linking between the silanol groups on PNFC and phosphate groups on APP. Composite properties were assessed using viscometry, thermogravimetric analysis (TGA), pyrolysis combustion flow calorimetry (PCFC), cone calorimetry, and dynamic mechanical analysis (DMA). Viscosity average molar masses of PLA decreased during extrusion, which was accelerated in the presence of APP based flame retardants. The use of PNFC resulted in the highest PLA molar mass of all flame retarded composites. Extruding the neat PLA lowered onset and peak decompositions, but the addition of APP based flame retardants modestly increased these temperatures. PCFC was found to be inconclusive in assessing beneficial flammability characteristics of the composites. The addition of 15% by mass IFR reduced the peak heat release rate by 45% and the total heat released by 20%, regardless of the carbon source. PNFC led to reduced smoke production compared to unmodified nanofibrillated cellulose (NFC) or pentaerythritol (PER). Use of APPePER reduced composite stiffness and the glass transition temperature. The use of APPeNFC and APPePNFC slightly increased composite stiffness, and did not significantly affect the glass transition temperature.

Free and glycosidically bound volatile compounds in juice and peel of Jincheng oranges were investigated. Solid phase microextraction (SPME) was used for extraction of free volatile compounds. Bound volatile compounds in juice were isolated by using Amberlite XAD-2 column adsorption and methanol elution. Subsequently, they were hydrolyzed by almond b-glucosidase. Acid hydrolysis was also applied on the release of the bound fraction in juice. Both free and bound volatile compounds were then determined by GC-MS. A total of 26 and 40 free volatile compounds were identified in juice and peel, respectively. Terpenes followed by aldehydes were the major free volatile compounds both in juice and peel. Eleven and ten aglycons hydrolyzed by enzyme were identified in juice and peel, respectively. Benzenic compounds and hydroxyl esters were the main bound volatile compounds in juice, while C 13 -norisoprenoid and monoterpenes were the most abundant bound volatile compounds in peel. 3-Oxo-a-ionol (41%) predominated in bound fraction of peel. Five aglycons hydrolyzed by acid were found in juice. p-Vinylguaiacol and eugenol were the two compounds found both after enzymatic and acid hydrolysis. Rhamnose, xylose, and glucose were determined as sugar moieties in juice.

The Food and Drug Administration (FDA) approved the New Drug Application for Wellbutrin sustained release (SR) 100 mg tablets on October 4, 1996. However, by 1998, the FDA expressed concern about the stability of this drug product based on an increase in the dissolution profile on storage. Data submitted in the annual report showed that this drug product could not meet the expiry of 18 months at the International Committee on Harmonization storage condition of 25°C/60% relative humidity. The FDA mandated a 12-month expiry and GlaxoWellcome tightened this further by instituting an expiry of 9 months. The FDA also requested a long-term solution to the stability of Wellbutrin SR 100 mg tablets. Investigations via colloidal solutions revealed that the dissolution rate increase on storage occurred due to acid hydrolysis of the release controlling polymer. This drug product was successfully reformulated by slowing the initial dissolution rate and having an increased ratio of release controlling polymer to acid stabilizer. The reformulation used the same ingredients and manufacturing unit processes as the original formulation. The reformulated drug product was approved by the FDA on October 11, 2000 with an 18-month shelf-life. The shelf-life was extended to 36 months in an annual update to the FDA on December 1, 2005.

Sodium hyaluronate (HA) of various molecular weights (MW) were prepared using acid hydrolysis, heat degradation, ultrasonic degradation, and irradiation on the same production batch. The molecular weights were determined using size exclusion chromatography (SEC) with in-line multi-angle laser light scattering (MALLS) and refractive index (RI) detection. The protein content for these samples were determined with the European Pharmacopoeia method for protein content, the Lowry assay and the Coomassie blue (BioRad, Bradford) assay. According to the Lowry assay, the determined protein contents increased with decreasing MW for all series of degraded HA. In the Coomassie blue assay, the protein level was independent of the MW. This was also shown by analysing a series of commercially available low molecular weight (LMW) hyaluronic acid products with the two assays. Further, degraded HA that had been reduced with NaBH 4 were studied, and also these gave higher protein contents in the Lowry assay, showing that it is not the increase in reducing ends that gives this artificial high responds. In general, the Coomassie blue assay was shown to be a better method for determination of protein contents in HA.

The enantiomers of 3-amino-1-methyl-1,2-dicarba-closo-dodecaborane were prepared by means of resolution of the racemic mixture via acylation by (S)-naproxen chloride followed by separation and subsequent acid hydrolysis of each of the diastereoisomeric amides. Partial racemization of enantiomeric 3-aminocarboranes was observed during acid hydrolysis.

The Gram-positive bacterial strain isolated from soil was identified as the non-pathogenic Microbacterium terregens. The exopolysaccharide (CPS) produced from M. terregens was obtained by isopropanol precipitation (13.72 g L À1 growth medium), The resulted exopolysaccharide was purified by chromatography on DEAE-cellulose and Sephacryl S-200 columns, when two polysaccharide fractions termed CPSI and CPSII were obtained. Structure features of CPSI and CPSII were investigated by a combination of chemical and chromatographic analyses, such as acid hydrolysis, methylation analysis, periodate oxidation-Smith degradation, HPLC, GC-MS, and IR. The results indicated that CPSI and CPSII were composed of glucose: mannose in a ratio of 2.7:1 and 3.2:1 with molecular weights 80 and 150 kDa, respectively. It has a backbone of (1 ? 4)-linked b-glucose residues, which occasionally branches at O-6. The branches were composed of (1 ? 4)-linked b-mannose residues. The antioxidant activity of the CPS, CPSI and CPSII was evaluated in-vitro by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay (RSA). CPSI fraction showed the highest antioxidant activity among the three fractions, with an IC 50 value of 230 lg mL À1. The effect of molecular weight of the polysaccharide on the improvement of the antioxidant potential seems to be significant.

Okara is a byproduct generated during tofu or soymilk production processes. Crude polysaccharide (yield 56.8%) was isolated by removing fat, protein and low molecular weight carbohydrates from initial okara. Crude okara polysaccharide was further divided into four soluble fractions and an insoluble residue fraction by extracting with 0.05 M EDTA + NH 4 oxalate, 0.05 M NaOH, 1 M NaOH and 4 M NaOH, with yields of 7.7%, 3.6%, 20.7%, 16.0% and 27.9%, respectively. Arabinose, galactose, galacturonic acid, xylose and glucose (only for the insoluble fraction) were the major constituent sugars. The primary sugar residues of okara polysaccharides were 1,4-linked β-galactopyranose, 1,5-and 1,3-linked α-arabinofuranose, 1,5-linked α-xylofuranose, 1,2-linked, 1,2,4-linked and terminal α-rhamnopyranose (or fucopyranose), and 1,4-linked β-glucopyranose (only for the insoluble fraction), indicating okara polysaccharides might contain galactan, arabinan, arabinogalactan, xylogalacturonan, rhamnogalacturonan, xylan, xyloglucan and cellulose.

Bionanofibers were isolated from Moringa Oleifera gum by carrying out combination of acid hydrolysis and probe sonication treatment. Acid hydrolysis of hemicelluloses was carried out to remove amorphous region. An increase in sulphuric acid concentration from 20 to 60 wt% accelerates the breakages in hemicelluloses molecules, leading to narrower, less polydisperse bionanofibers. After sonication, the fibers were cleaved into small fibers with dimensions on the nanoscale. The characterization of bionanofibers was performed by Scanning Electron Microscopy (SEM), Particle size, Differential Scanning Calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR). Surface morphology was observed by SEM which confirms presence of bionanofibers. Bionanofibers having diameter at 98 nm while length of 20 µm. The thermal analysis of Moringa oleifera gum was done by DSC. Fourier transform infrared spectroscopy (FTIR) showed that some breakages of intramolecular hydrogen bonds and glycosidic bonds held during hydrolysis reaction of Moringa Oleifera. The isolated nanofibers can be used in novel drug delivery system as platform to load the desired drug.

Ethanol may be produced using sugarcane bagasse as raw material through the Organosolv process with dilute acid hydrolysis, thus increasing ethanol production with the same cultivated sugarcane area. In this work simulations of bioethanol production from sugarcane juice and bagasse are carried out using software UniSim Design. A typical large scale production plant is considered: 1000 m 3 /day of ethanol is produced using sugarcane juice as raw material.

Organic-inorganic hybrid materials were synthesized by controlled hydrolysis of tetraethoxysilane (TEOS), methyltrimethoxysilane (MTES), synthetic wollastonite powders and polydimethylsiloxane (PDMS) in an ethanol solution. Aerogels were prepared from acid hydrolysis of TEOS and MTES with different volume ratio in ethanol, followed by addition of wollastonite powder and PDMS in order to obtain aerogels with 20 wt% of PDMS and 5 wt% of CaO of the total silica. Finally, when the wet gels were obtained, they were supercritically dried at 260 degrees C and 90 bar, in ethanol. In order to obtain its bioactivity, one method for surface activation is based on a wet chemical alkaline treatment. The particular interest of this study is that we introduce hybrid aerogels, in a 1 M solution of NaOH, for 30 s at room temperature. We evaluate the bioactivity of TEOS-MTES aerogel when immersed in a static volume of simulated body fluid (SBF). An apatite layer of spherical-shaped particles of uniform size smaller than 5 microns is observed to form on the surface of the aerogels after 25 days soaking in SBF.

Selective separation of citric acid and process optimization for its recovery from fermented broth through precipitation and acid hydrolysis were tried. A mathematical model has been proposed for yield. The experimental values are in good agreement with predicted values; the correlation coefficient was found to 0.9198.

Malto-dextrin, the mixture of glucose, maltose and dextrin is used in food industry, as bulking agent, fat replacer, and for medical/nutritional purpose. It is generally produced from cane sugar, maize (starch) etc. by acid or enzymatic hydrolysis. But presently its production rate is not so high. Malto-dextrin production from broken rice, a waste, is very beneficial because of its low cost and availability. In this paper, the objective of this study was to maximize the malto-dextrin production from rice starch by acid hydrolysis and also the effect of particle size on production of malto-dextrin. The rice starch was hydrolyzed by Hydrochloric acid (HCl). The range of the factors employed were particle mesh size, gelatinization pressure and time, saccharification time. The optimized gelatinization condition was 15psig for 30 minutes. The optimized acid hydrolysis condition was 67oC for 30 minutes. The optimized particle size was 18 meshes both for raw and parboiled rice. Maximum yie...