Starch Esters Research Articles

Esterification of Polymeric Carbohydrate Through Congener Cutinase-Like Biocatalyst.

Cutinase-like enzymes (CLEs) are bi-functional hydrolases, which share the conserved catalytic site of lipase and consensus pentapeptide sequence of cutinase. Here, we have genetically replaced the canonical amino acids (CAA) by their non-canonical fluorinated surrogates to biosynthesize a novel class of congener biocatalyst for esterification of polymeric carbohydrate with long-chain fatty acid. It is a new enzyme-engineering approach used to manipulate industrially relevant biocatalyst through genetic incorporation of new functionally encoded non-canonical amino acids (NCAA). Global fluorination of CLE improved its catalytic, functional, and structural stability. Molecular docking studies confirmed that the fluorinated CLE (FCLE) had developed a binding affinity towards different fatty acids compared with the parent CLE. Importantly, FCLE could catalyze starch oleate synthesis in 24 h with a degree of substitution of 0.3 ± 0.001. Biophysical and microscopic analysis substantiated the efficient synthesis of the ester by FCLE. Our data represent the first step in the generation of an industrially relevant fluorous multifunctional enzyme for facile synthesis of high fatty acid starch esters.

Properties of Potato Starch Roasted with Apple Distillery Wastewater.

This study aimed to produce starch esters by roasting potato starch with apple distillery wastewater at various temperatures and aimed to determine the effects of esterification conditions on selected properties of the modified preparations. Apple distillery wastewater was concentrated, mixed with starch (30 g of dry matter per 100 g of starch), dried, and roasted at temperatures of 110, 130 or 150 °C for 3 h. The resulting preparations were rinsed 30 times with a 60% ethanol solution, dried, and disintegrated. After that, the following analyses were performed: content of substituted acids (after alkaline de-esterification) with high performance liquid chromatography (HPLC); thermal characteristics with differential scanning calorimetry (DSC); swelling power and solubility in water at 80 °C; color changes with a colorimeter; rheology of the pastes based on the plotted flow curves; and the pastes’ resistance to amyloglucosidase. Starch treatments with apple distillery wastewater at 130 and 150 °C caused significant changes to its properties when compared to the control samples of native starch and starch roasted without wastewater, including: a lower temperature and heat of pasting, lower swelling power and solubility in water, darker color, higher resistance to amyloglucosidase, and the formation of pastes with a lower viscosity.

Synthesis and characterization of bio‐based intumescent flame retardant and its application in polyurethane

SummaryA novel bio‐based P‐N containing intumescent flame retardant melamine starch phytate (PSTM) was prepared via the reaction of phytic acid starch ester with melamine and characterized by Fourier transform infrared, scanning electron microscopy and thermogravimetric analysis (TGA). The effects of PSTM on thermal properties and flammability of rigid polyurethane (PU) foams were analyzed by TGA, limit oxygen index (LOI), vertical burning tests (UL‐94) and cone calorimeter measurement. The TGA results demonstrated that the thermal stabilities of PU/PSTM foam at high temperature was enhanced with the increasing additive amount of PSTM. The results showed that PU foam with 30 php PSTM (PU/PSTM‐30%) observed an LOI value of 25.9 and a UL‐94 rating of V‐0. Cone calorimetry data showed that peak heat release rate, total heat release and smoke production rate of PU/PSTM‐30% were distinctly lower than that of pure PU. Further experimental results demonstrated that PSTM promotes well charring of PU which could protect the foam from combustion. This work developed a novel bio‐based intumescent flame retardant by suing phytic acid and starch as the acid source and carbon source, respectively, which is of great significance to the preparation of environmental‐friendly flame retardants.

Effect of the Esterification of Starch with a Mixture of Carboxylic Acids from Yarrowia lipolitica Fermentation Broth on Its Selected Properties.

Potato starch was esterified with carboxylic acids contained in the fermentation broth from Yarrowia lipolitica yeast production. Various acid concentrations and various roasting temperatures were used to determine effects of process conditions on ester properties, including the number of acid residues attached to starch chains, starch susceptibility to amylolysis, and thermal characteristics of starch phase transitions. Study results demonstrated the effect of both the composition and the dose of the fermentation broth and of roasting temperature of starch on the number of acid residues attached to starch chains. Citric acid was more susceptible to esterification with starch (DS = 5.65%) compared to the α-ketoglutaric acid (DS = 0.12%). In the case of the latter, a higher degree of substitution was determined in the esters produced at higher roasting temperatures. The lowest digestibility (RS = 20%) was demonstrated for the starch esters with the highest degree of substitution with citric acid, whereas all starch esters showed decreased values of the thermal characteristics of pasting.

Rheological, textural, and digestible properties of fresh noodles: Influence of starch esterified by conventional and pulsed electric field‐assisted dual technique with full range of amylose content

This research was aimed to investigate the influence of esterified starches on the quality and texture of fresh noodles by adding starches with different amylose contents (<1%, 23%, 50%, 80%). The application of pulsed electric fields (PEF) during esterification can improve the introduction of acetyl groups. The peak viscosity of esterified waxy starch was decreased obviously from 4,238 to 79 mPa s by PEF assistance. Compared to the conventional method, esterified starch with higher amylose content (>23%) by PEF assistance can improve the appearance and elasticity of its uncooked noodles, while the addition of waxy starch esters showed an opposite trend. The influence of PEF-assisted modification on the increase in cooking yield and the decrease in hardness was more obvious compared to conventional method. Additionally, waxy starch esterified by the dual method exhibited a decrease in rapidly digestible starch content during in vitro digestion. Practical applications This study was to explore the effects of esterification on maize starch with full range of amylose content as well as the modified starches applied on noodles. Conventional and PEF-assisted dual methods have different influence on the rheological, cooking, and textural properties of noodles. Bright appearance and higher springiness, which were the desired properties of raw noodles for consumers, can be obtained by adding starch esters (except for waxy starch) modified by PEF-assisted esterification rather than the conventional method. It can expand the application of PEF technology on flour products, especially for noodles.

From high oleic vegetable oils to hydrophobic starch derivatives: II. Physicochemical, processing and environmental properties

Medium-substituted esters of starch and higher fatty acids, structurally identified in the first part of paper were subjected to further analyses, mainly to check application potential. In order to determine the possibility of using the esters in the packaging industry, the glycerol-plasticized starch esters were extruded on a single screw extruder in the form of a film. The mechanical properties tests consisted of tensile and tear strength. Hydrophobicity, water absorption and oil absorption were checked as the processing and functional properties. Environmental tests, such as phytotoxicity on monocotyledonous and dicotyledonous plants and biodegradability in soil under strictly controlled conditions of the vegetation hall were carried out. Esterification increased the hydrophobicity of the starch and the tensile and tear strength, without losing important environmental features such as biodegradability and non-toxicity. The obtained polymer materials give hope for their use in the production of new ecofriendly and biodegradable packaging.

Mechanical properties of starch esters at particle and compact level - Comparisons and exploration of the applicability of Hiestand's equation to predict tablet strength

Hydrophobic starch esters have potential as tablet matrix formers in controlled drug delivery. The mechanical properties of native starch (SN), starch acetate (SA) and starch propionate (SP) were studied at particle and compact level. Particle microhardness and modulus of elasticity were evaluated by nanoindentation. Force-displacement data of compressed powder were analyzed using Heckel in conjunction with piecewise regression, Kuentz-Leuenberger, Kawakita and Adams models, and yield pressure parameters were derived. Starches were characterized for chemical structure by Raman spectroscopy, crystallinity from powder x-ray diffraction (PXRD) patterns and surface energy from apparent contact angle measurements. A-type starch reflections were absent in the PXRDs of esters indicating greater amorphicity. Consequently, the particle microhardness of starch esters decreased leading to greater deformation during compaction and lower values of yield pressure parameters. These parameters increased with microhardness and ranked the starches in the order: SP < SA < SN. Fitting the experimental data into Hiestand's bonding index equation, a linear correlation (R2 = 0.902) was established between experimental and calculated tablet strength describing results of all starches, when Adams (το') yield pressure was used as the ‘effective compression pressure’ in the above equation.

Novozym435-Gold Nanoparticles Biohybrids as an Efficient Catalyst for Synthesis of Ferulic Acid Starch Ester.

Novozym435-gold nanoparticles biohybrids (NAuB) were synthesized and characterized in this work, with subsequent investigations on their catalytic activities and stability in compared with the initial form of Novozym435. This is a new way to modify immobilized enzyme by physical means. The elemental analysis of NAuB showed that Au was also the major element except C and O. The results of TEM and EDX demonstrated that gold nanoparticles (AuNPs) could be formed in the protein molecular network structure or on the surface of protein in the pores of Novozym435. The optimal process parameters for synthesis NAuB: synthesis temperature of 35 °C, HAuCl₄ concentration of 0.02 mg/mL, synthesis time of 24 h. Using the transesterification of starch with ferulic acid ethyl ester as the reaction model, preliminary results pointed to excellent stabilities, solvent tolerance and activities as compared with Novozym435. As for a isooctane:dimethyl sulfoxide system, transesterification of starch with ferulic acid ethyl ester was carried out at 6% (w/w) NAuB and 60 °C for 24 h, a maximum DS of 0.2650 was obtained.

Comparison of Three Methods to Determine the Degree of Substitution of Quinoa and Rice Starch Acetates, Propionates, and Butyrates: Direct Stoichiometry, FTIR, and 1H-NMR.

Rice and quinoa starch esters were prepared by acylation using short-chain fatty acid anhydrides with different chain lengths (acetic, propionic, and butyric anhydride). A direct stoichiometric method based on the acylation reaction was used to determine the degree of substitution (DS) and acyl content (AC). In addition, Fourier-transform infrared spectroscopy (FTIR) was used to validate the conformational changes of acylated starch and 1H-NMR was used as a DS reference method. DS by stoichiometric calculation was shown to be in agreement with FTIR and was comparable with DS obtained from Proton nuclear magnetic resonance (1H-NMR). Based on this study, stoichiometric calculation allows rapid and direct determination of substitution levels and acyl content without the loss of samples, which provides efficiency and optimization of manufacturing procedures in producing the desired level of esterified starches.

Effect of acryloylation on superabsorbency of starch copolymers

Abstract Starch is acryloylated and copolymerised without incorporating any vinyl monomer such as acrylic acid or acrylonitrile monomers to produce a superabsorbent copolymer. Fenton’s initiation system was used to produce polyacryloylated starch ester with varying degree of substitution. The copolymer from starch ester exhibited improved solubility, and an impressive water, saline, and solvents uptake. The superabsorbency of the samples is affected by the number of acryloyl groups on starch backbone. The starch ester with degree of substitution 0.8 had the highest water absorbency (102 g/g) in this experiment. Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and thermogravimetric (TGA) analyses were used to characterize the products.

Application of Octenyl Succinate Starch Ester (SSOS) in Peanut Beverage

In this paper, the effects of octenyl succinate starch ester, carrageenan, monoglyceride and sucr ose fatty acid ester compound emulsifier on the sensory evaluation of floating layer thickness, sedimentati on rate and precipitation were analyzed. the optimal scheme for making peanut protein beverage with octe nyl succinate starch ester was 0.09% xanthan gum,0.06% carrageenan,0.15% sucrose fatty acid ester and 0.15%monoglyceride. It is proved that the application of octenyl amber acid starch ester as stabilizer in peanut protein beverage is feasible.

Esterification of starch in search of a biodegradable thermoplastic material

Most of the products used in our everyday life are made of plastics. Even though plastics are very cheap and durable but plastic has a significant problem as due to its non-biodegradable nature plastic causes littering in river and sea, blockage in drains, degradation of landfill and it also causes various other environmental problems when dumped. To find out suitable alternatives of these plastic materials, researchers have preferred starch, an abundantly found and cheapest natural polymer and researchers have found some ways to convert starch in to thermoplastic material. Among these techniques, esterification process has gained most attention. This paper has tried to review some important researchers published on esterifying starch. By analyzing the research results of these researches this paper will try to find out the factors which control the end product properties so that the desired end product can be produced.

Oxidized konjac glucomannan-cassava starch and sucrose esters as novel excipients for sustained-release matrix tablets

A novel sustained-release matrix tablet was developed through wet granulation by using oxidized konjac glucomannan-cassava starch (OKGM-CS) and sucrose esters (SE) as excipients. OKGM-CS treated by dry heat exhibited low solubility and swelling power, indicating that it might be a potential adjuvant for sustained-release drug formulations. SE incorporation significantly decreased the porosity and swelling rates of tablets and retarded drug release. Tablets containing SE with an HLB value of 5 displayed better sustained-release performance, the cumulative release decreased from 94.36% to 83.29% and MDT increased from 4.50 h to 5.79 h. All these findings suggest the potential of OKGM-CS and SE as novel sustained-release agents for matrix tablets.

Mastering high ion conducting of room-temperature all-solid-state lithium-ion batteries via safe phthaloyl starch-poly(vinylidene fluoride)–based polymer electrolyte

In this work, an all-solid-state biomaterial electrolyte derived from phthaloyl starch and poly(vinylidene fluoride) (PVDF) was introduced. Phthaloyl starch (PS) was prepared with the starch and the phthalic anhydride via a chemical method. The introduction of C=O group through the starch esterification improved the migration of the lithium ions in the all-solid-state electrolyte membrane. The AC impedance test revealed that the addition of the phthaloyl starch promoted the conductivity of electrolytes, which can reach up to 2.04 × 10−4 S cm−1 at room temperature, and the electrochemical stability window (ESW) can achieve 4.20 V. Herein, the phthaloyl starch-PVDF–based electrolyte membrane possessed the lithium-ion transference number of 0.396. The half-cell Li/SPE/LiFePO4 had a better charge and discharge performance, that is, 93.9 mAh g−1 and 92.2 mAh g−1 after the 50th cycle at 0.5 C and at room temperature.

Synthesis and properties of thermoplastic starch laurates

Maize starch was allowed to react homogeneously in N,N-dimethylacetamide (DMAc)/LiCl with lauric acid activated with 4-toluenesulfonyl chloride, N,N′-dicyclohexylcarbodiimide/4-(1-pyrrolidinyl)pyridine, 1,1′-carbonyldiimidazole, and N,N-dimethylformamide (DMF) combined with oxalyl chloride. Characterization of the products by means of 13C NMR spectroscopy revealed different substitution patterns depending on the activation agent. The activation of lauric acid with DMF in combination with oxalyl chloride gave starch laurates of highest degree of substitution (DS), yield and reaction efficiency. The melting temperatures and the solubility of the thermoplastic starch laurates were found to depend on the DS, the substitution pattern, and on the molar mass of the starch esters.

Controlled biodegradability of functionalized thermoplastic starch based materials

The present work focuses on the preparation and characterization of biodegradable materials based on plasticized and chemically modified starch. During the experiments, the morphology, properties and biodegradability of the starch materials were influenced by the functionalization (acetylation, propionation) of the starch, different processing procedures and the use of plasticizers. The starch materials were prepared by either solution casting or melt mixing or by the combination of the two procedures, which strongly affected the degree of the material plasticization, its homogeneity, and the final morphology. FTIR spectroscopy qualitatively proved the esterification of starch by the intensity of signals associated with esters groups. The thermogravimetric analysis confirmed a gradual reduction in the water content proportional to the acetylation of starches, as well as noticeable changes in their thermal properties at the higher degree of substitution (DS). Signal intensities and weight losses derived from FTIR and TGA, respectively, were well correlated with DS. The morphological changes of the polysaccharide materials were visualized by microscopy techniques. The biodegradation rate of prepared materials was expressed as the percentage of carbon mineralization and was significantly retarded as a function of the starch acetylation. A remarkable effect of the material processing, the presence of plasticizers, and the propionation of the starch on biodegradation has been found.

Preparation of octenyl succinic anhydride‐modified cassava starch by the ultrasonic‐assisted method and its influence mechanism

As an effective physical method for starch modification, ultrasonic treatment can significantly improve the chemical activity and quality of starch, but its mechanism needs to be further investigated. In this paper, ultrasonic-modified cassava starch and octenyl succinic anhydride (OSA)-modified cassava starch with low degree of substitution were prepared under ultrasonic conditions. The effects of ultrasound on the structure and properties of native cassava starch and the quality of OSA-modified cassava starch were studied. The results showed that the crystallinity decreased from 30.7% to 26.4%, the reaction efficiency increased from 62.28% to 66.20%, and other characteristics also changed after 1 min of ultrasonic treatment. While the structure and properties of cassava starch changed differently after ultrasonic treatments for 8 min and 32–60 min. Consequently, these changes showed that ultrasonic treatment had a significant mechanochemical effect on starch granules. The quality of OSA-modified cassava starch was improved significantly and its influence mechanism was analyzed by the mechanochemistry theory. Practical applications During the esterification of starch, the dense arrangement of crystalline regions limits the reaction of esterifying agents with starch granules. This study showed that ultrasound exerted strong mechanical forces on starch granules, which promoted the production of free radicals and increased the free energy of starch molecules. Besides, the increase of mechanochemical active sites in starch granules was conducive to the homogeneous reaction of octenyl succinic anhydride (OSA) and starch molecules. Therefore, the quality of OSA-modified cassava starch prepared by ultrasonic-assisted treatment was significantly improved. This study provides a reference for the application of ultrasonic technology in other fields and also lays a theoretical basis for the industrial development of high performance-modified starch.

Characterization and Properties of Long‐Chain Fatty Acid Starch Esters Prepared with Regenerated Starch by Dry Method

AbstractRegenerated starch (RS) prepared from 14% urea/4% NaOH aqueous solution is used as a raw material to synthesize esterified starch. Starch stearate (SS), a kind of long‐chain fatty acid starch ester, is synthesized through the esterification of RS with stearic acid by a dry method under normal pressure and without an organic solvent or catalyst. Scanning electron microscopy, Laser Particle Sizer, Fourier transform infrared, 1H NMR, X‐ray diffraction, differential scanning calorimetry, and thermogravimetric analysis are used to characterize and analyze the prepared SS. The effect of degree of substitution (DS) on the properties of SS, such as moisture adsorption, transparency, emulsion ability (EA) and emulsion stability (ES), freeze–thaw stability, and retrogradation, is also studied. The results show that the prepared SS has better EA and ES, good freeze–thaw stability, and excellent retrogradation, all of which increase with the increase of DS. The transparency of SS pastes is significantly improved when its DS is under 0.3. The moisture adsorption of SS decreases due to the introduction of stearate groups. All these improved properties make SS a better material for a myriad of industrial applications.

Effect of octenyl succinic anhydride starch ester by semi-dry method with vacuum-microwave assistant

Corn starch was esterified with octenyl succinic anhydride (OSA), in which semidry method assisted with vacuum-microwave treatment was used under the alkalescent condition. The effect of vacuum treatment on esterification was studied. The products were characterized by Fourier transform infrared (FT-IR) spectroscopy, 1H nuclear magnetic resonance (NMR), scanning electron microscopy (SEM) and X-ray diffraction. And the emulsifying properties were investigated with the emulsifying capacity (EC), emulsion droplet size and confocal laser scanning microscopy (CLSM). The degree of substitution (DS) of OSA starch increased significantly (ρ < 0.05) assisted by the vacuum-microwave treatment with the same dosage of reactant compared with the microwave only. The results confirmed the formation of OSA starch prepared by the method, all reactions occurred mainly on the surface of granules, and had no significant effect on the starch crystallinity. The OSA starch was a good polymeric surfactant with good abilities both in hydrophilic and lipophilic. The emulsifying capacity, degree of substitution of the OSA starch prepared by the method attractively showed vast potential for scale production.

Synthesis of long-chain fatty acid starch esters in aqueous medium and its characterization

Long-chain fatty acid starch esters are prepared by esterification of stearic acid or lauric acid with corn starch in urea/NaOH aqueous solutions. Effect of esterify condition on the degree of substitution (DS) and the structure and performance of the products are studied. The synthesized starch stearate and starch laurate are obtained a DS of 0.065 and 0.074, respectively, higher than the reported values by the water medium method. Esterification of starch is proved by Fourier transformed infrared and 1H nuclear magnetic resonance. The structure and thermal properties of starch esters are confirmed by X-ray diffraction, Scanning Electron Microscope, Thermogravimetry and Differential Scanning Calorimetry. The results show that the starch esters, with lower crystallinity than starch, has better thermostability, emulsibility, transparency, freeze-thaw stability and moisture absorption than native starch, but higher glass transition temperature (Tg) within the limited DS.