Acetic Anhydride Concentration Research Articles

Tunning the hydrophobic performance and thermal stability of pectin film by acetic anhydride esterification

Pectin, a polysaccharide found in plant cell walls, is characterized by a high abundance of hydroxyl groups and carboxylic acid groups, which results in a strong affinity for water and limits its suitability as a film material. This study aimed to modulate the esterification degree of PEC films by adjusting the concentration of acetic anhydride, and assess the impact of acetic anhydride esterification modification on the properties of the resultant PEC films. The results demonstrated successful grafting of acetic anhydride onto the galacturonic acid ring in the PEC molecule through the esterification process. The hydrophobicity, thermal stability, barrier properties, and mechanical properties of the esterified PEC films were investigated. Among the various concentrations tested, the E-PEC-0.25 film exhibited the highest contact angle of 103.46° and tensile strength of 33.44 MPa, showcasing optimal performance. The E-PEC-0.1 film achieved the highest esterification degree of 0.94 and elongation at a break of 21.11 %. It also exhibited the transparency of 11.66 and the lowest water vapor transmission rate of 0.56 g·mm/(m2·h·kpa). Additionally, TGA and DSC tests revealed enhanced thermal stability of the esterification-prepared films. These findings highlight the potential of acetic anhydride tuning as a promising strategy for optimizing pectin film production.

Effect of acetylation treatment on the physicochemical and morphological properties of three sweet potato starches (Ipomoea batatas)

Abstract. Kusumaningsih T, Firdaus M, Handayani DS, Juneasri FTI, Ananta FM. 2023. Effect of acetylation treatment on the physicochemical and morphological properties of three sweet potato starches (Ipomoea batatas). Biodiversitas 24: 3038-3044. Irrespective of their promising applications, native starches still present some limitations for food industry purposes as a result of their unsatisfactory physicochemical characteristics. Nevertheless, these shortcomings can be overcome with the proper modification efforts. In this study, three different starches of sweet potatoes (white, yellow, and purple) were isolated from Ipomoea batatas (L.) Lam. have been modified by employing an acetylation reaction using acetic anhydride at concentrations of 3%, 4%, 5%, 6%, and 7%. The change in the Degree of Substitution (DS) value along with the presence of carbonyl group peaks and a decrease in the intensity of the hydroxyl group peaks after acetylation confirmed the success of the starch modification. DS showed a maximum value at 7% acetic anhydride concentration in acetate starch of 0.0492, 0.0509, and 0.0718 for white, yellow, and purple acetate sweet potatoes, respectively. The DS value of starch acetates demonstrates results that are consistent with the Food and Drug Administration (FDA) regulations (less than 2.45%), indicating that modified starches have the potential to be used in the food industry. Surface morphology analysis using the Scanning Electron Microscopy (SEM) instrument also confirmed the success of the acetylation process, where the acetylated starch surface became rougher than the original starch surface. Several physicochemical properties, including amylose, amylopectin, swelling power, water solubility, and Water Binding Capacity (WBC), were determined and showed that starch acetate has favorable characteristics for further applications in the food industry.

Performance evaluation of mercerization and acetylation on hardness of raffia palm fibre

As the demand for environmentally friendly products rises and global awareness on reducing toxicities in manufacturing increases, the exploitation of plant-based raw materials like raffia palm fiber requires closer attention. In this study, the effect of sodium hydroxide and acetic anhydride concentration on the hardness of raffia palm fiber at varying drying temperature and fiber length were investigated. The treatments were carried out using 10% sodium hydroxide solution and 5% acetic anhydride at oven drying temperatures of 70oC for mercerized fiber and 50oC for acetylated fiber with varying fiber length of 50mm, 60mm, 70mm and 80mm. Findings show hardness values of 257HR and 370HR for 10% NaOH at 70oC and 5% acetic anhydride at 50oC respectively showing a 30.38% rise in Rockwell Hardness value in the acetylated fibers over the mercerized cohorts. Remarkably, these results were obtained at ideal fiber lengths of 60mm in both treatments. Hence, acetylation treatment at 5% acetic anhydride concentration and 50oC oven-drying temperature using 60mm fiber length offered optimal hardness value for raffia palm fiber. This is highly recommended for industrial commercialization for composites in the automobile, construction, manufacturing, medical, sports, oil and gas industries. In addition, the results from this study will open new economic values for Nigerian Raffia Palm fiber as potential reinforcement material for both domestic and international markets and applications.

Effect of Acetic Anhydride Concentration on the Physical and Functional Properties of Acetylated Cassava Starches

Effect of Acetic Anhydride Concentration on the Physical and Functional Properties of Acetylated Cassava Starches

Effect of pH and acetic anhydride concentration on physicochemical characteristics of acetylated sago starch

Acetylation is a method of chemically modified starch that can be used to improve the physicochemical properties of starch. The aim of the study was to obtain the pH and concentration of acetic anhydride which gave the best effect on the physicochemical characteristics of acetylated sago starch. The study was arranged using a completely randomized design with a factorial pattern in combination with a suspension pH of 7.0; 8.0; 9.0 and 10.0 with acetic anhydride concentrations of 3%, 6%, 9%, 12% and 15% (volume/weight). The parameters of research include acetyl percent, degree of substitution (DS), water holding capacity (WHC), oil holding capacity (OHC), swelling power, solubility and degree of clarity of the paste. The results at research showed that the combination suspension pH of 8 and 15% concentration of acetic anhydride gave optimal physicochemical characteristics of acetylated sago starch. The all concentrations of acetic anhydride (3 to 15%, v/w) were acetyl percent, DS, solubility and the degree of clarity of the paste increased with the increasing. The WHC and OHC tend the decreasing with the increasing concentration of acetic anhydride. Swelling power was stable with increasing concentration of acetic anhydride.

Physicochemical properties and solubility of sweet potato starch-based edible films

This study aimed to develop a sweet potato starch (SPS)-based edible film with improved water solubility. Initially, types of sweet potatoes were used, and their characteristics were analyzed to select the most appropriate variety for edible films. Shingeonmi was finally selected, and a chemical modification of starch, acetylation with different concentrations of acetic anhydride (1, 5, and 9 mL), was conducted to improve the water solubility. During the film-forming process, amidated pectin (AP) and calcium chloride (CaCl2) were also compounded to enhance the solubility. The developed native and acetylated SPS films, with or without the two substances, were further used to investigate various physicochemical properties and water solubility. Acetylated SPS-based films with AP and CaCl2 showed excellent water solubility (99.16%) than the native SPS one, indicating the beneficial effect of variables (acetylation, AP, and CaCl2) for enhanced water solubility. These results imply the potential use of the developed water-soluble film to package food ingredients and products such as vegetables, bakery, meat, or seafood due to the enhanced solubility and edibility.

Improving delayed-release potential of winged bean starch by acetylation

Winged bean starch was acetylated for evaluation of its effects on the physicochemical and release properties of starch. The modification was carried out with 0.8, 1.6, and 2.4 g of acetic anhydride. The degree of substitution (DS) increases proportionally from 3.85±0.2 to 5.37±0.09 with the increase in acetic anhydride concentration. The acetylation of winged bean starch increased swelling and solubility power with the transition of temperatures. The result showed that both amylose content (2.69±0.82%-2.92±0.84%) and water holding capacity (102.87±0.02-106.70±0.04) increased proportionally with the increase in acetic anhydride concentration. In vitro dissolution study was performed in USP type II apparatus using pH 1.2 and 6.8 as dissolution media. The formulations prepared with acetylated starches especially AS1 showed drug release of 68.92±0.22% in 2 h compared to 78.32±0.51–91.03±0.66% release in native starch formulations in that same period indicating improved delayed release property of acetylated winged bean starch.

PROPIEDADES FISICOQUÍMICAS, FUNCIONALES Y ESTRUCTURALES DE ALMIDONES NATIVOS Y ACETILADOS OBTENIDOS A PARTIR DE LA PAPA (Solanum tuberosum) var. ‘ÚNICA’

La acetilación es una modificación química de la estructura del almidón que consiste en reemplazar un determinado número de grupos hidroxilos por grupos acetilos empleando anhídrido acético. Este proceso depende de ciertos factores, tales como la fuente de almidón, la concentración del anhídrido acético, el tiempo de reacción y el pH. El objetivo de este estudio fue caracterizar el almidón nativo (obtenido de la papa var. ‘Única’) y los almidones acetilados, mediante espectroscopía FT-IR, y evaluar sus propiedades fisicoquímicas (contenido de amilosa, color) y propiedades funcionales (poder de hinchamiento, solubilidad, capacidad de retención de agua, propiedades térmicas y propiedades de formación de pasta). Las muestras estudiadas fueron el almidón nativo (AN) y los almidones modificados por acetilación con diferentes concentraciones de anhídrido acético al 5 %, 10 % y 15 % (AAc5%, AAc10% y AAc15%). Los contenidos de amilosa aparente para el almidón nativo y almidón acetilado (AAc15%) fueron 17,3 y 31,4 %, respectivamente. Los parámetros de color no cambiaron con la acetilación. La temperatura y entalpía de gelatinización, así como el perfil de formación de pasta, disminuyeron para los almidones acetilados con respecto al almidón nativo. Durante la prueba de formación de pasta, el almidón acetilado con 15% de anhídrido acético presentó un bajo valor de la viscosidad máxima (1599,4 mPa∙s) con respecto al valor observado para el almidón nativo (3065,8 mPa∙s).

Structure and Functional Properties of Arenga Starch by Acetylation with Different Concentrations of Acetic Anhydride

Structure and Functional Properties of Arenga Starch by Acetylation with Different Concentrations of Acetic Anhydride

Optimisation of acetylation parameters for reduced moisture absorption of bamboo fibre using Taguchi experimental design and genetic algorithm optimisation tools

Natural fibres have good weight-to-strength ratio which has made it a material of interest for scientists and engineers. However, the major drawback for outdoor application of natural fibres is its hydrophilic nature. In this study, attempt was made to render bamboo fibre hydrophobic through acetylation with acetic anhydride at room temperature. The functional water absorption properties were studied and the acetylation parameters, such as chemical dosage and acetylation time, were optimised. Taguchi Orthogonal Array was used for the experimental design. Based on the Taguchi design, a regression equation was generated which served as an objective function for Genetic Algorithm. Acetylation reduced the percentage water absorption of Bambusa Vulgaris fibre from 196.4% in un-acetylated fibre down to 45% in acetylated fibres within the feasible design space. The optimal parameter setting generated with genetic algorithm is 15% acetic acid concentration, 50minutes of time soaked in acetic acid, 5% acetic anhydride concentration and 30 minutes time soaked in acetic anhydride. Under the optimum condition, the percentage water absorption was 44%. A confirmation experiment validated the effectiveness of the Genetic Algorithm result. Keywords: Acetylation, Bamboo Fibre, Taguchi, Optimisation, Genetic Algorithm

Acetylation of Amaranthus viridis starch: Modeling and process parameters optimization.

The optimum reaction conditions for the derivation of acetylated (esterified) starch using response surface methodology (RSM) and artificial neural network (ANN) were studied. All the independent variables (starch solids, acetic anhydride concentration, and reaction time) were of significant (p < .05) importance in achieving esterified starch of Amaranthus viridis. Optimum conditions of 152.46 g of starch, 11 ml of acetic anhydride and time of 2.92 min with corresponding acetyl content and degree of substitution (DS) of 1.74% and 0.06, respectively, were established for ANN. The RSM gave optimum conditions of 149.57 g (starch), 10.38 ml (acetic anhydride) and 3 min (time) with corresponding acetyl content and DS of 1.61% and 0.06, respectively. The order of priority of the process variables was established as acetic anhydride (42.59%), starch solids (33.90%), and reaction time (23.51%). The results provided useful information on development of economic and efficient acetylation process for modification of A. viridis starch.

Optimization and Kinetics Evaluation of Bachmann Process for RDX Synthesis

Abstract 1,3,5-Trinitro-1,3,5-triazacyclohexane (RDX) is one of the high explosives extensively used for various military and civil applications. RDX is predominantly used in warheads, the most advanced solid propellants for guns and rockets and in plastic bonded explosives for improving performance characteristics. Thus the increasing demand of RDX necessitates study on reaction engineering and reactor stability in view of enhancement of safety as well as productivity. In present study, Bachmann process has been studied in detail for understanding role of reagents, time and temperature on reaction yield. Reaction rates of RDX and side products have been evaluated at various temperatures using continuous flow technique. Second order reaction was found sensitive towards temperature and concentrations of nitric acid and acetic anhydride. Higher magnitude of activation energy was evaluated for side products (25.2 kcal/mol) than RDX (18.71 kcal/mol). Optimum temperature of reaction has been obtained on profiling its progression at various reaction rates and temperature. Further, reactor stability analysis has been carried out to identify the safe operation conditions for this highly exothermic reaction. Effect of coolant flow rate and temperature as well as feed temperature has been analyzed on heat removal rate to obtain the safe regime of reaction. The information related to maximization of RDX formation and safe design of continuous process has been presented in manuscript.

Analysis of Adiabatic Batch Reactor

A mixture of acetic anhydride is reacted with excess water in an adiabatic batch reactor to form an exothermic reaction. The concentration of acetic anhydride and the temperature inside the adiabatic batch reactor are calculated with an initial temperature of 20°C, an initial temperature of 30°C, and with a cooling jacket maintaining the temperature at a constant of 20°C. The graphs of the three different scenarios show that the highest temperatures will cause the reaction to occur faster.

Acetylation of rice starch in an aqueous medium for use in food

The degree of acetylation controls the use of starch acetate, since the FDA (Food and Drug Administration USA) recommends an acetyl groups' percentage below 2.5 g/100g for a food application. The objective of this work was to evaluate the effects of the acetic anhydride concentration, in an aqueous solution, on the degree of acetylation, in physical, thermal, pasting and morphological properties, and enzymatic susceptibility on rice starch acetylated with the acetyl groups' percentage up to 2.5 g/100g. The rice starch was acetylated using different concentrations of acetic anhydride (5 g/100g, 10 g/100g and 20 g/100g, starch db). Acetylation increased the peak viscosity, breakdown, final viscosity, retrogradation and pasting temperature and reduced the hardness of the gels, as well as their adhesiveness and gumminess; however this did not affect the morphology and susceptibility to hydrolysis by the α-amylase of the starch. The acetylated starches using 10 and 20 g/100g acetic anhydride showed lower swelling power and solubility compared to native starch.

Physico-chemical properties of acetylated starches from Indian black gram (Phaseolus mungo L.) cultivars.

Starches separated from three black gram cultivars were modified by acetylation and compared to their native starches. Acetylation was carried out by treating starches with 0.04 and 0.08g of acetic anhydride/g of starch dry weight basis (db) at 25°C. The extent of acetylation increased proportionally with the concentration of acetic anhydride used. Retrogradation of acetylated starch pastes decreased significantly (p ≤ 0.05) as revealed by significant decrease in syneresis, increased freeze thaw stability and increased light transmittance. The pasting curves of 10.7% starch slurries showed that acetylation decreased the setback viscosity values by 51.2-82.8% and pasting temperature by 3.1-5.6°C than respective native starches. Differential scanning calorimetry observations also revealed significant decrease in gelatinisation temperature of acetylated starches than native starches. Hardness and adhesiveness of starch gels varied between 10.3 and 32.6g and 4.6-82.3gs, respectively which were significantly lower than corresponding native starch gels.

Effect of acetyl esterification on physicochemical properties of chick pea (Cicer arietinum L.) starch.

Acetyl esterification of isolated Bengal gram starch was carried out using acetic anhydride as reactant. Modification of native starch at variant concentrations of acetic anhydride (6, 8 and 10%, w/w) resulted in modified starch with 2.14, 3.35, 4.47% acetyl content and 0.082, 0.130 and 0.176° of substitution (DS) respectively. The acetyl esterification of native starch brought significant changes in physicochemical properties with respect to pasting behavior, granule morphology, thermal properties and retrogradation profile. Acetyl modifications of native starch increased swelling capacity, water absorption power and oil absorption capability by 17, 13 and 20% respectively. Acetylation has decreased pasting temperature, pasting time, final viscosity and set back viscosity due to increase in amylsoe content, hydrogen bonding and porosity of starch granule. The acetyl modification was confirmed by IR spectra with the presence of an ester carbonyl group (C = O) at 1720.3cm(-1) and absorption band at 174.8cm(-1). In DSC evaluation there was decrease in To, Tp, Tc and ΔH of acetylated starch than native starch which resulted in reduced retrogradation by 56%.

Physicochemical and release characteristics of acetylated Indian palmyrah retrograded shoot starch

The aim of the present study is to determine the influence of serial modifications, including retrogradation followed by acetylation on morphological, physicochemical and drug release properties of retrograded Indian palmyrah (Borassus flabellifer L.) shoot starch. The acetylated retrograded starches prepared by using different concentrations of acetic anhydride were shown a degree of substitution (DS) in the range of 0.16–0.55. Acetylation of retrograded starch produced significant morphological changes from rough to smooth surface. The amylose content, water holding capacity, swelling and solubility power tend to increase with increase in DS. A strong peak at 1751 and 1032cm−1 confirms the formation of acetylated retrograded starch. The TGA data reveal that with increase in DS there is an increased thermal stability and decreased bound water of starch. The elemental analysis also confirms the addition of acetyl groups because of increased carbon and hydrogen content. The matrix tablets of acetylated retrograded starch with high DS showed a delayed release in gastric pH and sustained release in simulated intestinal fluid. Overall, this result suggested that acetylated retrograded starch with high DS are thermally stable and can be used for formulating protein and peptide drugs for colon targeting.

Thermal and Tensile Mechanical Behavior of Acetic Anhydride Treated Silk Fibres

Acylation of fibres can provide a route to have materials with better water proofing capability. In our present study, silk fibres were treated with various concentration (5, 10 and15 wt.%) of acetic anhydride aqueous solution and then thermal properties, tensile mechanical behaviour and moisture content of acetic anhydride treated silk fibres were studied. Raw silk fibres were taken as control for comparison. It was found that elastic modulus and tensile strength of silk fibres were increased with increasing acetic anhydride concentration while elongation at break was decreased with increase of acetic anhydride content in solution. Silk fibres treated with 15 wt. % of acetic anhydride solution exhibited about 141% (from 17 GPa to 41 GPa) improvement in elastic modulus. It was also found that acetic anhydride treated silk fibres displayed higher thermal resistance and lower moisture content as compared to untreated silk fibres.

Study on Esterification Characteristics of TEMPO-Oxidized Cellulose

Oxidized cellulose acetate (OCA) with carboxylic acid group on C-6 position of glucose is a kind of biodegradable functional materials which can be dissolved in organic solvents. First, cellulose was oxidized with TEMPO (2, 2, 6, 6-tetramethyl-piperidyl-1-oxyl) oxidation system, and then OCA was produced via esterification by reacting the oxidized cellulose with acetic anhydride. The influence factors such as carboxylic content of oxidized cellulose, reaction temperature, reaction time, and concentration of acetic anhydride on degree of substitution (DS) of acetyl group and intrinsic viscosity ([η]) of OCA were investigated. The result revealed that the DS of acetyl group can be increased effectively from 2.61 to 2.74 by increasing reaction temperature from 50°C to 80°C, and from 2.58 to 2.72 by prolonging reaction time from 40min to 180min, but the [η] of the product decreased at the same time. An increase in concentration of acetic anhydride led to an increase in DS and [η] of OCA. As the carboxyl content increased from 0.383 mmol/g to 0.797 mmol/g, the DS of acetyl group decreased from 2.81 to 2.73. That result revealed the carboxyl content also has a great influence on the esterification characteristics.

Physicochemical properties of acetylated starches from some Indian kidney bean (Phaseolus vulgaris L.) cultivars

SummaryStarches separated from four kidney bean cultivars were modified by acetylation to reduce retrogradation and increase gel stability and compared with respective native starches (data of native starch reported by Wani et al., 2010). Acetylation was carried out by treating starches with 0.04 and 0.08 g of acetic anhydride per gram of starch dry weight basis (dwb) at 25 °C and pH between 8.0 and 8.5. The extent of acetylation increased proportionally with the concentration of acetic anhydride used. The pasting curves of 10.7% starch determined by Rapid Visco Analyzer at 160 rpm showed that acetylation decreased the setback viscosity values by 0.64–34.58% and pasting temperature by 4.4–9.2 °C when compared with the native starch. Differential scanning calorimetry observations also revealed significant (P ≤ 0.05) decrease in gelatinisation temperature of acetylated starches than the corresponding native starches. Hardness of starch gels varied between 14.3 and 44.0 g, which was significantly (P ≤ 0.05) lower than the corresponding native starch gels.