Starch Esters Research Articles

Effect of amylose content in morphological, functional and emulsification properties of OSA modified corn starch

Octenyl succinic starch esters were prepared from three corn starches with different amylose content; namely, waxy (5.43%), normal (25.16%) and Hylon VII (65.84%). The degree of substitution varies from 0.0103 for waxy starch to 0.0125 for Hylon VII, meaning that the degree of substitution is positively correlated with the amylose content. Scanning electron microscopy images showed that the esterification reaction affected only the granule surface while leaving the integrity of the granules. Solubility and water retention capacity were increased with the OSA modification, with the effect more pronounced for higher amylose contents. X-ray analysis revealed that the crystallinity type was not affected by esterification. FTIR analysis corroborated the changes in the hydrated and ordered structures of starch granules. Emulsification tests showed that octenyl succinic starch ester was an effective emulsifier for stabilization of oil-in-water emulsions. In particular waxy and Hylon VII starches induced high stabilization degrees as revealed by long-term stability of oil-in-water emulsions.

Dual-frequency ultrasound for ultrasonic-assisted esterification.

The optimization of wheat starch esterification (acetylation) with a high degree of substitution was performed through response surface methodology (RSM) via various concentrations of reagents (acetic anhydride), pHs, and temperatures under various ultrasonication frequencies (25, 40, and 25 + 40 kHz). According to RSM methodology, optimized samples were selected by achieving high degrees of substitution at various frequencies, temperatures, and pHs. Solubility, swelling, X‐ray, RVA, DSC, freeze–thaw stability, texture, and SEM analysis of the optimized samples were performed at three frequencies. X‐ray pattern exhibited a more significant reduction in the crystallinity percentage of esterified starch at frequency 25 + 40 kHz compared with 25 kHz, 40 kHz, and native starch. According to DSC analysis, To, Tp, Tc, and enthalpy of gelatinization (ΔH gel) were lower in AC at frequency 25 + 40 kHz compared with AC at frequency 25 and 40 kHz and N starches. According to morphology analysis, in acetylated starches at 25 and 40 kHz, the surfaces and small granules underwent more damage, whereas in 25 + 40 kHz, large granules were more affected than small granules. Upon acetylation, freeze–thaw stability and textural properties of the starch significantly increased and decreased, respectively. The peak and final viscosity of acetylated starch increased (25 + 40 kHz ˃ 25 kHz ˃ 40 kHz ˃ N starch).

Preparation and characterization of emulsion stabilized by octenyl succinic anhydride-modified dextrin for improving storage stability and curcumin encapsulation

In our study, octenyl succinic anhydride (OSA)-modified dextrin was prepared and characterized as a novel emulsifier to improve the stability of emulsion and curcumin encapsulation. Fourier-transform infrared spectroscopy demonstrated the occurrence of esterification between OSA and dextrin (Mw = 1.041 × 104 g/mol). The absolute value of ζ-potential of OSA-dextrin increased (from 25.37 mV to 34.57 mV) with increasing OSA addition (from 0% to 8%), and then kept constant. Confocal laser scanning microscope results showed that the debranching and esterification of starch improved the oil droplets distribution and reduced the droplet size of emulsions. The emulsifying stability of emulsions coated by dextrin was greatly improved with OSA modification. The particle size of emulsion decreased significantly when the addition of OSA increased during storage. OSA-modified dextrin was in a position to increase encapsulation efficiency of curcumin. This research may increase the utilization of emulsions stabilized by OSA dextrin in food industry.

Preparation of pure gum raw materials-low brown algae application

Octenylsuccinate starch ester, also called pure gum, is non-toxic and odourless modified starch which is widely used in many food fields. This study synthesized pure gum in a reaction kettle using the low molecular weight trehalose and octenyl succinic acid. An orthogonal test was carried out to find how the reaction factors affect the synthetization of octenylsuccinic acid polysaccharide ester and to optimize the reaction at single factor level. The optimal products were obtained using 1:2 of octenylsuccinic acid: alginic acid, catalysed by 0.1% p-toluenesulfonic acid catalyst for 1.5 h at 200°C under vacuum conditions. The gained product contains up to 46% of seaweed gel monoesters. The degree of esterification of the polysaccharide is controlled by the use of the small-molecule trehalose. Compared with the traditional methods, our process can reduce raw material cost and improve emulsification stability of pure gum. These all can significantly improve the market competitiveness of pure gum products.

Micro/nanoparticles containing potassium sorbate obtained by the dialysis technique: Effect of starch concentration and starch ester type on the particle properties

Micro/nanoparticles based on native (NTS), acetate (ATS) and oleate (OTS) tapioca starch were produced by dialysis technique as new materials with capacity to support the antimicrobial potassium sorbate (PS). The influence of NTS concentration (0.33, 3.33 and 33.33 mg NTS/mL DMSO) on the particle size and PS content (PSC) was analyzed. Dialysis promoted the disruption of granules and the re-association of the starch producing mainly nanometric particles (<450 nm diameter) when diluted solutions were tested while microparticles (20–200 μm diameter) were obtained from concentrated solutions, probably due to an increased aggregation in systems with high concentration of biopolymer molecules. In addition, the NTS nanoparticles showed an increased capacity to retain PS (6889 - 1372 ppm) than NTS microparticles (1243 - 916 ppm). Starch esterification process modulated physical properties and PSC of the modified particles from ATS and OTS concentrated solutions. The ATS nanoparticles were the systems with the highest PSC (2564 ppm). The average molecular weights (MW) of the resulting particles diminished in comparison with the MW of the NTS, ATS and OTS. All nanometric fractions showed negative z-potential and spherical shape. The developed particles could be applied for food quality optimization, both as carriers of PS for preventing the oxidative degradation or to control the release of this preservative along storage.

Organic Acids of the Microbiological Post-Culture Medium as Substrates to be Used for Starch Modification.

This study aimed to identify the feasibility of producing highly-substituted starch esters via thermal modification of starch using a post-culture medium of Yarrowia lipolitica yeast. This manuscript describes a successful attempt at potato starch modification with a post-culture medium of Yarrowia lipolitica yeast with different concentrations of organic acids. Starch preparations produced by roasting (130 °C) and these produced by starch reaction with a synthetic acid mixture were compared in terms of the types and number of acid residues esterified with starch. The effectiveness of starch esterification was found to depend on medium composition and to be higher upon the use of a synthetic acid mixture. In addition, a higher reactivity with starch was demonstrated for citric acid than for α-ketoglutaric acid. The highly-substituted starch esters formed as a result of potato starch modification with post-culture medium were characterized by decreased values of thermal parameters of pasting characteristics, determined with a differential scanning calorimeter (DSC), and by compromised resistance to amylolysis. The intensity of these changes increased along with an increasing total percentage of starch ester substitution.

Hierarchical Structure and Thermal Property of Starch-Based Nanocomposites with Different Amylose/Amylopectin Ratio

Starch-based materials with reinforced properties were considered as one of the most promising materials to replace the petro-based packaging products, and actually, the molecular structures of starch usually determined the structures and properties of end-used starchy products. Here, starch-based nanocomposites were fabricated by starch esters derived from native starches with different amylose contents and organically modified montmorillonite (OMMT). The fractured surface under scanning electron microscopy (SEM) exhibited wrinkles formed by macromolecular aggregation owing to the interaction competition between the plasticizer and nanofiller with the starch ester. The more intense interaction within amylopectin-rich films promoted the formation of much randomly exfoliation of OMMT observed by Transmission electron microscopy (TEM). As the amylose content increased, the interaction between the starch ester and the nanofiller was weakened, leading to the dispersion morphology of an ordered arrangement and partly intercalated structures in the dimension of 12.92 to 19.77 nm. Meanwhile, such interaction also affected both the inner ordered structure integrity of starch ester and the layer structure consistency of nanofiller according to X-ray diffraction results. Further, the stronger interaction between amylopectin and the nanofiller endowed higher thermal stability to the amylopectin-rich starch-based nanocomposites. In short, these results are beneficial for the application of starch-based nanocomposites in the food packaging industry by regulating the interaction between starch and nanofillers.

Enzyme‐Catalyzed Starch Esterification in Deep Eutectic Solvent

AbstractFor the first time the enzymatic esterification of starch in deep eutectic solvent (DES) was reported using DES of choline chloride (ChCl)‐ethylene glycol (EG) as reaction solvent/medium, Novozyme 435 as catalyst, and PEG 400 as phase transfer agent to synthesize starch decanoate, starch laurate, and starch palmitate. The product samples of esterified starches were characterized by FTIR, 1H NMR, GPC, SEM, XRD, and DSC tests. The results showed that, the degrees of substitution were in the range of 0.07‐0.19 and the addition of PEG 400 was helpful to increase the DS. The optimal esterification temperature for DS was 338 K in the range studied. The degradation of starch was found to be minor due to the use of long‐chain fatty acid and relatively low reaction temperatures. The dissolution, gelatinization, esterification, and recrystallization of starch in DES broke the particles into smaller ones and altered the crystal structure of native starch while the aggregation between particles was increased and the degree of crystallinity was decreased for the esterified starch with the length of carbon‐chain in the fatty acids.

Turning Industrial Waste into a Valuable Bioproduct: Starch from Mango Kernel Derivative to Oil Industry Mango Starch Derivative in Oil Industry

After industrial mango processing, tons of residues such as peels and kernels are discarded as waste. Nevertheless, almost 60% of the mango kernel is due to starch on a dry weight basis. Herein, starch from mango (Manguifera Indica L.) kernel was applied to obtain a starch fatty ester with vinyl laurate, in DMSO, under basic catalysis. FTIR, 1H and 13C NMR confirmed that a starch ester with a degree of modification of 2.6 was produced. TGA showed that the modified starch has higher thermal stability than its precursors and higher than a vinyl laurate/starch physical blend. SEM data showed that granular shape and smooth surface on mango starch changed after chemical modification to a continuous and shapeless morphology. This industrial reject derivative behaved as an efficient alternative environmentally friendly fluid loss controller in oil drilling fluids, even in conditions of high temperatures and high pressures (HTHP) drilling

Rheological characterization of cold water soluble rice (Oryza sativa) starch lactates and citrates prepared via alcoholic-alkaline method

The present study prepared citrates and lactates from rice starch which were then given alcoholic-alkaline treatment to produce cold water soluble (CWS) starches. These chemically modified starches were then compared in terms of rheological parameters to their hot water soluble starches (without alcoholic-alkaline treatment). FTIR spectra showed characteristic peak between 1710–1727 cm−1 which confirmed esterification of starch via citrate and lactate groups. All samples demonstrated viscoelastic character i.e. storage moduli (G′) exceeded loss moduli (G″). Both CWS and HWS starch citrates prepared by addition of 40 g citric acid to 100 g of starch exhibited highest G′ and G″ suggesting highly structured and strong gels. Dynamic frequency and temperature sweep clearly showed that alcoholic alkaline treatment disrupted the granular conformity due to gelatinization of starch and as a result CWS starches were more susceptible to break down. Steady shear flow test confirmed that all samples were non-Newtonian while results of In-shear structural recovery measurements indicated anti-thixotropic behavior of CWS starch lactates.

Preparation and Characteristics of Starch Esters and Its Effects on Dough Physicochemical Properties

As a recyclable natural material, starch is an important raw material in food and other fields. The native starch by esterification could improve the performance of the original starch and expand its range of application. This article reviews the preparation process of acetylated distarch adipate, starch sodium octenylsuccinate, starch acetate, hydroxypropyl starch, and starch phosphate and research into the influence of starch esters on dough. At the same time, it forecasts the trend of starch esters and application prospect in the future research.

Hydrophobic and Melt Processable Starch‐Laurate Esters: Synthesis, Structure–Property Correlations

ABSTRACTA controlled esterification of starch to replace the OH moieties with bio‐derived medium chain fatty acids, and the changes in the polymer structure and properties for material applications is investigated in this research. The esterification is conducted via a homogeneous esterification process using an activated lauric acid (C12) in the presence of a base catalyst. The degree of esterification through the replacement of hydroxyl groups of starch was estimated using elemental analysis (EA) and proton NMR. The effect of the modification on the structural and material properties of the modified starch polymer is elucidated by evaluating the changes in morphology, network thermal stability, hydrophobicity, solubility profile, and thermal transition events. Scanning electron microscopy imaging reveals structural changes ranging from surface roughness to complete disruption depending on the degree of substitution. This is confirmed by XRD. Because of the esterification of starch, the resulting polymers become melt processable thermoplastic that forms a transparent film with an elastic storage modulus of up to 226 MPa at room temperature. This shows that the starch–fatty acid polymer can be used for various industrial and advanced material applications without any other plasticizers or modifiers. The final material is completely bio‐based, and is expected to be biodegradable in the environment. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 2611–2622

In vitro α-amylase and pancreatic lipase inhibitory activity of Cornus mas L. and Cornus alba L. fruit extracts

Less-common fruits from Cornus spp. (Cornaceae), also named dogwoods, have shown antidiabetic, antibacterial and anti-allergic properties and are thus considered a source of phytochemicals that are beneficial to human health. The study aimed to compare the chemical compositions of the aqueous and ethanolic extracts of lyophilized fresh-picked and commercially available dried fruits of Cornus mas (Cm, cornelian cherry) and Cornus alba (Ca) fruits using HPLC-DAD-MS/MS method. Simultaneously, the α-amylase and pancreatic lipase (PL) inhibitory activities of the prepared extracts were compared by in vitro fluorescence assay based on the kinetic hydrolysis of starch or oleate ester of 4-methylumbelliferone (MUO), respectively. Additionally, a bio-assay guided identification of compounds potentially responsible for the inhibition of pancreatic enzymes was performed. Iridoids (loganic acid, cornuside) and anthocyanins (pelargonidin 3-O-galactoside) were identified in the Cm fruit extracts. Flavonoids, such as quercetin and kaempferol derivatives, were detected in the Ca fruit extracts. The chromatographic separation of the constituents of Ca fruit provided a fraction containing phenolic acids derivatives, which inhibited PL activity by 69.9 ± 4.5% at a concentration of 7.5 μg·mL−1. The IC50 of hydroxytyrosol glucoside, isolated from the most active Ca fraction, was 0.99 ± 0.10 mg·mL−1 indicating other constituents responsible for the fraction activity. The most active subfraction from Cm fruit (7.5 μg·mL−1), which inhibited PL activity by 28.3 ± 1.5%, contained pelargonidin 3-O-galactoside. Loganic acid and cornuside in highly pure form did not inhibit lipase activity. The phytochemical constituents of Cm, and particularly of Ca fruit extracts, can inhibit pancreatic enzymes and thus might be considered effective preparations in the prevention and control of hyperlipidemia related diseases.

Production of Esterified Starches with Increased Resistant Starch Content by an α‐Hydroxy Acid‐Catalyzed Route

Resistant starch (RS) refers to the portion of starch that is not broken down by human enzymes in the small intestine, and thus reaches the large bowel of healthy individuals. In the large bowel RS is fermented by colonic microflora producing short chain fatty acids (SCFA) – predominantly acetate, propionate, and butyrate – that are known to contribute substantially to large bowel health. Currently, there is an increasing interest in obtaining RS by esterification of starch with target SCFA, due to its capacity to deliver significant quantities of the particular esterified SCFA to the colon. In the current contribution an α‐hydroxy acid‐catalyzed methodology, which has recently proven useful for esterifying starch, was used to produce acetylated, propionylated, and butyrylated corn starch samples with varying degree of substitution (DS) (0.05–0.75). Results showed the suitability of the route to produce the RS4 starch type, with RS contents that increased with DS as a consequence of a larger steric hindrance effect caused by a higher number of ester groups introduced. Data also indicated that the DS conferred to starch was the key factor conditioning its resistance, whereas RS content showed to be independent of the resulting esterified starch structure and the type of ester group introduced.

Characterizations of modified cassava starch with long chain fatty acid chlorides obtained from esterification under low reaction temperature and its PLA blending

ABSTRACTIn contrast to typical starch esterification in an aqueous solution, which are carried out at elevated to ambient reaction temperatures, a low reaction temperature was applied in this study to minimize the starch chain hydrolysis. The physical properties of the modified starch, obtained from an esterification of cassava starch with long-chain fatty acid chlorides carried out in aqueous media at 4°C, were characterized using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and contact angle measurements. The modified starches show improvement in thermal stability and hydrophobicity, which can be further optimized by varying the types of acid chlorides and the reaction conditions. The starch products have high potential for use as fillers for biodegradable polymers, especially polylactic acid (PLA), as their tunable hydrophobicity can impose strong effect on controlling of the PLA's hydrolytic degradation rate for specific applications. Results on mechanical properties of the blends between the modified starch and PLA show an improvement in modulus of the polymer.

Study on Esterification Reaction of Starch Isolated from Cassava (Manihot esculeta) with Acetic Acid and Isopropyl Myrtistate Using Ultrasonicator

Cassava starch is a polysaccharide consists of amylose and amylopectin. This research was purposed to modify the starch isolated from local cassava (Manihot esculenta). Modification was undertaken to study the esterification reaction of cassava starch with acetic acid and with isopropyl myristate. Moreover, morphology observation was also conducted both for original starch and its modification yields. It was found that cassava’s starch was isolated in 16.4% yield as a white powder. Esterification on the starch provided DS value 0.549 for ratio 1:2 of starch-acetic acid. It gave DS value 0.356 for ratio 1:3 of starch-isopropyl myristate. Treatment by ultrasonication from 0 to 60 minutes was significantly improved the DS value to 0.549 for starch-acetic acid. But it gave DS value to 0.413 for 30 minute ultrasonication of starch-isopropyl myristate. In addition, morphology of the starch observed by microscope gave different features with starch ester acetate and starch ester myristate. The original starch consists of granules, but starch ester acetate indicates a non-granules shape (amorf solid). Moreover for starch ester myristate shows a rather bigger size of granules, and all of the granules afforded were round and oval.

Microwave pretreated esterification improved the substitution degree, structural and physicochemical properties of potato starch esters

Potato starches were pretreated with 600 W microwave and then acetylation was carried out with acetic anhydride and glacial acetic acid (1:1 in volume). The microwave-pretreated-acetylation remarkably modified the physicochemical properties of starch compared with the single acetylation method. The starch granules exhibited rough surfaces but maintained integrity and the crystal structure changed to C-type after microwave-pretreated-acetylation. Meanwhile, the microwave-pretreated starch esters exhibited the higher substitution degree, the higher infrared absorption peak intensity and the lower relative crystallinity compared to un-microwave-pretreated ones. The solubility of microwave-pretreated starches was higher at 80–90 °C than un-pretreated samples, while the swelling power of microwave-pretreated starches was lower at 60–90 °C under a same esterification level. Particularly, the solubility of microwave-pretreated samples at 90 °C was 2.11 times higher than un-pretreated ones, while the swelling power of microwave-pretreated starches exhibited 52.8% lower than un-pretreated samples at 90 °C under the 12 mL/100 g esterification level. The peak viscosity and the gelatinization enthalpy of microwave-pretreated starches were lower than un-pretreated ones under the same esterification level. Particularly, these values of microwave-pretreated starches were 2332 mPa s lower and 8.46 J/g lower than un-pretreated ones at the 12 mL/100 g esterification level, respectively.

Biosorbents based on esterified starch carrying immobilized oil-degrading microorganisms

The complex sorbents based on hydrophobized starch, which contain oil-degrading microorganisms, have been proposed for effective sorption and utilization of petroleum-related pollutants. The sorbents were made on the base of benzoic, lauric and stearic acid esters of starch with degrees of substitution of 0.4–1.1. The esterification of starch was carried out by the reaction with acyl chlorides of the corresponding acids in an aqueous-organic medium. The structure of the esters was studied by SEM, IR and NMR spectroscopy. As a result of porous hydrophobic structure, these sorbents are capable of binding and retention of petroleum products on the water surface, and keeping the flotation for at least 30days after the petroleum products sorption. The test of biodegradability of the obtained samples revealed that the modified starches can be degraded by microscopic fungi, therefore they do not cause secondary pollution. The cultures of yeast Rhodotorula glutinis VKM Y-2993D and bacteria Pseudomonas libanensis VKM B-3041D immobilized on the sorbent facilitate the rapid utilization of accumulated petroleum products.

Effects of hydrothermal-alkali and freezing-thawing pre-treatments on modification of corn starch with octenyl succinic anhydride

Pre-treatments by freezing/thawing (F/T) and hydrothermal-alkali (HA) were used in the modification of starch with octenyl succinic anhydride (OSA). In comparison with OSA-modified starch prepared without pre-treatment (degree of substitution, DS=0.0172; reaction efficiency, RE=73.9%), HA pre-treatment increased the DS of OSA-starch and RE of subsequent OSA modification (0.0185 and 79.7%, respectively). In contrast, F/T pre-treatment gave the opposite results (0.0152 and 65.5%, respectively). OSA modification markedly increased the viscosities but decreased the gelatinization parameters of native starch. Esterification of starch by OSA was confirmed with Fourier transform infrared and Raman spectroscopy, which indicated markedly decreased short-range molecular orders of native starch. The present study showed that HA pre-treatment before OSA modification is an efficient way to improve the reaction efficiency of OSA with starch and thereby to modify the pasting properties of starch. F/T pre-treatment did not increase the reaction efficiency of starch with OSA.

Transesterification of sago starch and waste palm cooking oil in densified CO2

In this work, the synthesis of biodegradable and yet renewable thermoplastics materials through a transesterification reaction of sago starch and waste palm cooking oil (WPO) in densified CO2 as the solvent is reported. The aim of this research is to investigate the potential used of sago starch and WPO as raw materials in the thermoplastics starch synthesis. The starch esters was successfully synthesized using sago starch and WPO as reagent in densified CO2 as shown from the presence of carbonyl group (C=O, 1743 cm-1) in the FT-IR spectra coupled with the presence of the proton (1H-NMR) of the fatty acid in the starch backbone (0.8 – 2 ppm). The product crystallinity decreases as shown in XRD results and resulting with a change in the thermal properties (melting and crystalline temperature) of the products. In addition, the products show a different granular morphology and a higher hydrophobicity compared with native sago starch. This research shows the potential used of sago starch and WPO in the thermoplastics starch synthesis and opens a new perspective on the product application.