Acetylated Corn Starch Research Articles

Functional, eco-friendly, and starch-based nanocarriers with sustained release of carvacrol for persistent control of tomato gray mold

Carvacrol (Car) is a promising botanical fungicide. However, the volatile and easily oxidizable characterization of Car hinders its practical application. Herein, an eco-friendly, starch-based nanopesticide (Car@ACS) was successfully constructed by encapsulating of Car within acetylated corn starch, enabling sustained release to prolong its efficacy. In vitro release experiments showed that the release of Car from commercial carvacrol soluble concentrate (Car SL) was 98.4% within 4 h, while that of Car@ACS released 36% within 4 h and 79% within 48 h, demonstrating the endowed sustained release property of the starch nanoparticles. Meanwhile, in vitro antimicrobial activity experiments revealed the fungicidal ability of the prepared Car@ACS and carvacrol technical (Car Tech) with the same concentration of active ingredient to be comparable Botrytis cinerea. In the 7-day pot experiment, the efficacy of the Car@ACS group (56.9%) against B. cinerea was significantly greater than that of the Car SL group (33.3%). In addition, the Car@ACS formulation improved the foliar retention of Car compared to Car SL in hydrophilic cucumber and hydrophobic peanut leaves. Finally, biosafety tests indicated that Car@ACS did not significantly affect the germination or growth of tomato seedlings. Therefore, the advantages of long-lasting disease control properties, improved foliar retention and eco-friendliness indicate that Car@ACS has significant potential to facilitate the application of volatile botanical fungicides.

Acetylated corn and potato starches as an alternative to the toxic inorganic coagulants/flocculants for wastewater treatment

Inorganic coagulants/flocculants have been key in water treatments. However, last years, it has been reported the potential contamination that these give to the environment and serious risks to human health. For that reason, new eco-friendly alternatives have been the subject of exploration and research. This work focused on developing and elaborating a natural flocculant based on corn and potato starches, and its application in industrial wastewater treatments. Starches were isolated from corn and potato, and modified by acetylation method with the aim of improve its solubility. The morphological characterization using SEM identified the effects of acetylation process, the surface of acetylated corn and potato starches presented small erosions. The vibrational characterization via FTIR elucidated the physicochemical changes owing to acetylation. It found the replace of hydroxyl groups of α-glucose by the acetyl ones of amide I. A loss of the crystalline quality of corn starch were identified through structural characterization utilizing DRX. The partial replacement of hydroxyl by acetyl groups due to acetylation induced structural modifications corroborated employing the area under curve of the diffraction patterns. In the case of potato starch, its characteristic hexagonal crystalline structure was favored by the acetylation process, as it exhibited a more defined diffraction pattern. The thermal analysis by means of TGA found three thermal events for the acetylated potato starch and four for the acetylated corn starch. The fourth thermal event in the acetylated potato starch was associated with the ester presence of the added group. The thermal degradation occurred at lower temperatures as mass loss curves showed that acetylation weakened the polymer chains. The pH of zero point charge was 6.52 for the acetylated corn starch and 5.55 for the acetylated potato one, indicating that anionic contaminants be retained at a pH below 6.52 and 5.55 for each case, and the removal of cationic contaminants will favor at pH above these values. The efficiency determination of the modified starch-based flocculant was performed utilizing a jar test at different concentrations to find the optimal concentration of the coagulant/flocculant. Turbidity, color, pH, and electrical conductivity measurements were made before and after the water treatment. These results indicated that both corn and potato starches showed good performance as coagulants/flocculant. The kinetics for adsorption was study using the pseudo-first and pseudo-second order kinetic models, the intra-particle diffusion model, and the Elovich kinetic one. These analyzes identified that the absorption process is governed by chemisorption mechanisms since the pseudo-second order kinetic model was the most accurate for describing the absorption kinetic of both acetylated corn and potato starches according to the R2, SSE, MSE, and RMSE.

Functional characterization of edible films based on reactive extrusion acetylated corn starch

Functional characterization of edible films based on reactive extrusion acetylated corn starch

Application of dual modified corn starch as a polymer for the colon targeted direct compressible budesonide tablet

In the current study, dually modified retrograded acetylated corn starch was prepared with improved physicochemical properties than its native form. The modified starch was utilized as a polymer for colonic targeted direct compressible tablets with budesonide as a model drug. In vitro release study showed the formulation exhibited pH dependent release profile with 81.38% drug release within the entire ileocolonic region. This suggests a significant improvement in the release profile over currently available colon targeted oral budesonide formulations that release most of the drug before the large intestine. In the dual modified starch, retrogradation resulted in the conversion of starch granules into small crystallites which blocked the void spaces of the polymer network and thereby retarded its disintegration. Esterification enhanced hydrophobicity, decreased swelling power and surface porosity of the starch. The direct compressible budesonide tablet using retrograded starch acetate polymer can therefore be a novel treatment option for ileocolonic irritable bowel disease.

Acetylated corn starch as a fat replacer: Effect on physiochemical, textural, and sensory attributes of beef patties during frozen storage

Acetylated corn starch was used as a fat replacer in beef patties and its effect on the physicochemical, textural, and sensory attributes of the patties was assessed during frozen storage (-20 °C) for 60 days. The results showed that acetylated corn starch enhanced the redness, moisture retention, thickness, and sensory attributes of the patties (P ≤ 0.05). It also reduced the firmness, cooking loss, diameter reduction rate, and dimensional shrinkage of the patties (P ≤ 0.05). The patties contain 15% acetylated corn starch showed a microstructure similar to that contain 15% animal fat as examined by scanning electron microscopy. Patties containing acetylated corn starch showed high scores of physicochemical properties and sensory attributes, which revealed the beneficial use of this modified starch in meat industry. In conclusion, acetylated corn starch improved the physicochemical properties and sensory attributes of beef patties and can thus be used as fat replacer in meat products.

Preparation and Physicochemical Properties of Modified Corn Starch-Chitosan Biodegradable Films.

Starch is a biopolymer with enormous potential for generating new biodegradable packages due to its easy availability and low cost. However, due to its weak functional properties, limitation of its interaction with some hydroxyl groups and evaluation of blends with other polymers are necessary in order to improve its performance. Glycerol-plasticized acetylated corn starch films were developed using the casting method, and the impact of incorporating chitosan (TPS:CH) in various proportions (75:25, 50:50, and 25:75 v/v) was studied in the present research. The effect of chitosan ratios on the physical, mechanical, water-vapor barrier, and thermal properties of the film was studied. Chitosan-protonated amino groups promoted the formation of intermolecular bonds, improving tensile strength, thermal stability, hydrophobicity, water adsorption capacity, and the gas barrier of starch films. The results show that the film composed of TPS25-CH75 proved to be the best barrier to water vapor; thus, these composite films are excellent choices for developing biodegradable packaging for the food industry.

Mechanical, physical and microstructural properties of acetylated starch-based biocomposites reinforced with acetylated sugarcane fiber

Fiber-reinforced starch-based biocomposites provide an environmentally friendly alternative to replace petroleum-based plastics. Nevertheless, these materials present structural stability problems owing to their hydrophilicity. Therefore, a chemical modification is usually necessary. Hence, the aim of this research is to obtain biocomposites based on acetylated corn starch (AS), acetylated sugarcane fiber (AcSF) and glycerol. Also, to assess the AcSF content (FC, 0.0–20.0%) and glycerol content (GC, 20.0–30.0%) on their physical, mechanical and microstructural properties. A single-screw extruder and central composite rotatable design were employed. Due to acetylation and possible interaction between matrix-fiber, there was an improvement in water resistance; while the mechanical properties were enhanced by increasing FC up to 12.0%. Biodegradability recorded a range of 24.2–39.3%. Microstructural analysis evidenced the extrusion process effect, chemical modification and new interactions formation. It was found that an optimum blend was of FC = 12.0% and GC = 24.0%. The acetylation of both sugarcane fiber and corn starch allowed us to obtain eco-friendly materials with good mechanical properties and water resistance.

Study on physicochemical properties, digestive properties and application of acetylated starch in noodles.

The physicochemical and digestive properties of acetylated corn starch with different degrees of substitution were studied, which were prepared by microwave pretreatment and acetate esterification. Native corn starch-wheat noodles, acetylated corn starch-wheat flour noodles and native wheat noodles were prepared and their properties were compared. The results showed that the transparency, condensation volume ratio, hydrophilicity and lipophilicity of modified corn starch increased with increasing of substitution degree, which were 4.0% to 12.1%, 21.11% to 31.78%, 0.73 g/g to 0.91 g/g and 0.66 g/g to 0.88 g/g, respectively and the rate of water evolution decreased from 44.9% to 33.3%. Fourier transform infrared spectroscopy showed that acetyl group was successfully introduced. Scanning electron microscopy showed that microwave pretreatment and group introduction made the surface of starch granules locally porous and rough. Differential scanning calorimetry showed lower onset temperature, peak temperature, conclusion temperature and enthalpy than native corn starch, which proved that acetylated corn starch reduced the content of rapidly digestion starch and increased the content of slow digestible starch and resistant starch. At the same time, the results showed that the color, texture and tensile properties of noodles with acetylated corn starch were improved. It showed that acetylated corn starch prepared by microwave pretreatment and acetate esterification had certain application prospects.

Preparation and characterization of acetylated maltodextrin and its blend with poly(butylene adipate-co-terephthalate)

Acetylated maltodextrins (AMDs) were synthesized. It was found that maltodextrin (MD) was easily acetylated to form AMDs with high degree of substitution (DS). The DS of the prepared AMDs was much higher than that of acetylated corn starches (ACSs) obtained under the same reaction conditions. The differential scanning calorimetry (DSC) measurements clearly highlighted that AMD underwent a glass transition at about 109°C. Moreover, AMD possessed higher thermal stability than MD. The AMD with DS 2.13 (AMD2.13) was melt-blended with poly(butylene adipate-co-terephthalate) (PBAT) to fabricate novel PBAT/AMD polymer blends. Rheological measurements indicated that AMD2.13 had a plasticizing effect on PBAT. Moreover, scanning electron microscopy (SEM) measurements indicated good interfacial adhesion between PBAT and AMD2.13. The onset temperature of non-isothermal melt crystallization of PBAT increased from 81.95 to 92.19°C due to the favorable heterogeneous nucleation effect. Mechanical tests showed that the yield strength of the PBAT/AMD blends was enhanced.

The effect of amylose content and level of oxidation on the structural changes of acetylated corn starch and generation of free radicals

This study was aimed at determining the effect of starch oxidation on its acetylation, structure of starch granules, and generation of free radicals. Corn and waxy corn starches were oxidised by NaClO applied in doses of 10, 20, and 30g Cl/kg of starch, and then acetylated using acetic acid anhydride. The carboxyl, carbonyl, acetyl groups were determined in modified starches. Structural properties of starch granules were evaluated based on molecular weight distribution, gelatinisation, crystallinity, specific surface, intrinsic viscosity. EPR measurements were carried out to establish starch susceptibility to UV irradiation induced generation of free radicals. It was found that the number of carbon centered radicals was dependent on the kind of starch and its chemical modification. Study results allowed concluding that the applied modifications contributed to significant changes in starch granules that were determined not only by the amylose content of starch but also by the degree of its oxidation.

Biological Control of Aflatoxin Contamination in U.S. Crops and the Use of Bioplastic Formulations of Aspergillus flavus Biocontrol Strains To Optimize Application Strategies.

Aflatoxin contamination has a major economic impact on crop production in the southern United States. Reduction of aflatoxin contamination in harvested crops has been achieved by applying nonaflatoxigenic biocontrol Aspergillus flavus strains that can out-compete wild aflatoxigenic A.flavus, reducing their numbers at the site of application. Currently, the standard method for applying biocontrol A.flavus strains to soil is using a nutrient-supplying carrier (e.g., pearled barley for Afla-Guard). Granules of Bioplastic (partially acetylated corn starch) have been investigated as an alternative nutritive carrier for biocontrol agents. Bioplastic granules have also been used to prepare a sprayable biocontrol formulation that gives effective reduction of aflatoxin contamination in harvested corn kernels with application of much smaller amounts to leaves later in the growing season. The ultimate goal of biocontrol research is to produce biocontrol systems that can be applied to crops only when long-range weather forecasting indicates they will be needed.

Preparation and characterization of acetylated starch nanoparticles as drug carrier: Ciprofloxacin as a model

The objective of this study was to characterize in-vitro the potential of acetylated corn starch (ACS) particles as a matrix for the delivery of ciprofloxacin (CFx). ACS was successfully synthesized and optimized by the reaction of native corn starch using acetic anhydride and acetic acid with low and high degrees of substitution (DS). The nanoprecipitation method was applied for the formation of the ACS-based nanoparticles, by the dropwise addition of water to acetone solution of ACS under stirring. The effects of acetylation and nanoprecipitation on the morphology and granular structure of ACS samples were examined by the FT-IR, XRD, DSL and SEM techniques. The efficiency of CFx loading was also evaluated via encapsulation efficiency (EE) in ACS nanoparticles. The average degree of acetyl substitution per glucose residue of corn starch was 0.33, 2.00, and 2.66. The nanoparticles size of the ACS and ACS-loaded with CFx were measured and analyzed relative to the solvent:non-solvent ratio. Based on the results, ACS nanoparticles with DS of 2.00 and water:acetone of 3:1 had 312nm diameter. Increasing DS in starch acetate led to increase in the EE from 67.7 to 89.1% and with increasing ratio of water/acetone from 1:1 to 3:1, the EE raised from 48.5 to 89.1%. X-ray diffraction indicated that A-type pattern of native starch was completely transformed into the V-type pattern of acetylated starch. The scanning electron microscopy showed that the different sizes of pores formed on the acetylated starch granules were utterly converted into the uniform-sized spherical nanoparticles after the nanoprecipitation.

Retrogradation kinetics of cross-linked and acetylated corn starches under high hydrostatic pressure

Retrogradation kinetics of conventionally and high hydrostatic pressure (HHP)-assisted chemically modified (cross-linked with sodium trimetaphosphate/sodium tripolyphosphate (STMP/STPP) and acetylated with acetic anhydride) corn starches were investigated. During storage at 4°C, the glass transition temperature (Tg′) and the ice melting enthalpy were measured using differential scanning calorimetry (DSC), and relative crystallinity was measured using an X-ray diffractometer (XRD). In both conventionally and HHP-assisted modified corn starches, the Tg′ value and relative crystallinity increased during first 7–10 days of storage, then stabilized, whereas the ice melting enthalpy decreased until 10 days of storage, then remained constant. HHP-assisted modified starch showed different retrogradation kinetics from conventionally modified starch. However, the retrogradation rates of both samples were lower than for native corn starch. Although the Tg′ value, the ice melting enthalpy, and relative crystallinity represent different physicochemical properties, all can be used as indicators for evaluation of starch retrogradation.

Synthesis and Physicochemical Characteristics of Acetylated Corn Starch under Microwave Assistance

Native corn starch(NCS) was acetylated by a microwave-assisted method using vinyl acetate(VAc) as an acetylating agent and potassium carbonate K2CO3as a catalyst. Acetylated corn starch(ACS) was characterized by Fourier-transform infrared spectroscopy(FT-IR), scanning electron microscopy(SEM), and X-ray diffraction(XRD). The physicochemical properties, adhesive properties and biodegradability of ACS were systematically investigated. The results show that the physicochemical properties of ACS were improved compared with NCS: the hydration capacity raised, solubility, swelling power and paste clarity increased; the intrinsic viscosity, apparent viscosity decreased, rheological property were improved; the syneresis decreased, anti-retrogradation were enhanced. The adhesion to polyester/cotton fibers of ACS was enhanced, which compensated for the insufficient adhesion to hydrophobic fibers of native starch. BOD5/CODcrvalue of ACS was outclasses that of PVA-205.

Microwave‐assisted synthesis and characterization of acetylated corn starch

In this study, native corn starch (NCS) was acetylated by a microwave‐assisted method using vinyl acetate as an acetylating agent and potassium carbonate as a catalyst. Acetylated corn starch (ACS) was characterized by Fourier‐transform infrared spectroscopy, SEM, and XRD. The optimum conditions of acetylation (i.e., reaction temperature, exposure time, and catalyst concentration) were assessed. The physicochemical properties of ACS including swelling power, solubility, intrinsic viscosity, apparent viscosity, paste clarity, and syneresis were studied. Furthermore, the adhesion property and sizing performance were evaluated. The results revealed that the physicochemical properties of ACS were improved compared with those of NCS. The adhesion force of ACS to polyester/cotton fibers increased significantly; the sizing properties of ACS were better than those of NCS. ACS, which has potential applications in the textile industry, is an ideal substitute for polyvinyl alcohol.

Preparation and characterization of acetylated corn starch–(PVOH)/clay nanocomposite films

Acetylated corn starch (ACS)-based clay (NaMMT) nanocomposite films, with or without addition of polyvinyl alcohol (PVOH), were prepared by casting with glycerol as a plasticizer. The obtained nanocomposite structure was ascertained by XRD study for all polymer–clay nanocomposites. XRD patterns are indicative of an intercalated nanocomposite structure. Mechanical and thermomechanical properties of polymer nanocomposites were studied. The addition of clay induces significant reinforcing effects in the thermoplastic ACS systems. Replacement of glycerol with PVOH in the ACS–NaMMT system results in superior mechanical strength, due to the creation of hydrogen bonds between the ACS and the PVOH chains. Enhancement in water barrier properties was observed for all nanocomposite films, which reaches up to 67% for acetylated starch–PVOH–clay nanocomposites in comparison to acetylated thermoplastic starch, as indicated by water vapor transmission measurements.

Fabrication and Characterization of Size-Controlled Starch-Based Nanoparticles as Hydrophobic Drug Carriers

Acetylated corn starch was successfully synthesized and optimized by the reaction of native corn starch with acetic anhydride and acetic acid in the presence of sulfuric acid as a catalyst. The optimal degree of substitution of 2.85 was obtained. Starch-based nanoparticles were fabricated by a simple and novel nanoprecipitation procedure, by the dropwise addition of water to acetone solution of acetylated starch under stirring. Fourier transform infrared spectrometry showed that acetylated starch had some new bands at 1750, 1375 and 1240 cm(-1) while acetylated starch nanoparticles presented the identical peaks as the drug-loaded acetylated starch nanoparticles and the acetylated starch. Wide angle X-ray diffraction indicated that A-type pattern of native starch was completely transformed into the V-type pattern of Acetylated starch and starch-based nanoparticles show the similar type pattern with the acetylated starch. The scanning electron microscopy showed that the different sizes of pores formed on the acetylated starch granules were utterly converted into the uniform-sized spherical nanoparticles after the nanoprecipitation. The encapsulation efficiency and diameter of nanoparticle can be adjusted by the degree of substitution, the volume ratio of nonsolvent to solvent and the weight ratio of acetylated starch to drug. It was also depicted that the release behaviors of drug-loaded nanoparticles depend on the size of nanoparticles and the degree of substitution of the acetylated starch. Release studies prove that the starch-based nanoparticles with uniform size can be used for the encapsulation of hydrophobic drug and attained the sustained and controllable drug release carriers.

Synthesis, optimization and characterization of acetylated corn starch with the high degree of substitution

Acetylated corn starch (ACS) was synthesized by the reaction of native corn starch (NCS) with acetic anhydride (AA) and acetic acid in an aqueous medium in the presence of p-toluenesulfonic acid (PTSA) as a catalyst. The factors that could affect the degree of substitution (DS) of corn starch were investigated which included the reaction temperature and time, the volume ratio of AA to acetic acid and the usage of the catalyst PTSA. The optimal DS of 2.85 was obtained. Fourier transform infrared (FTIR) spectrometry showed new bands at 1733, 1375 and 1252cm−1. As DS increased, the bands at 3400cm−1 and 1083cm−1 were gradually weakened. The scanning electron microscopy (SEM) of the ACS indicated that the exterior and interior of native starch were destroyed by the esterification. Wide angle X-ray diffraction revealed that the peaks at 15°, 18°, 20° and 23° were diminished, while the peak at 21° became more distinct as the DS increased. Differential scanning calorimetry (DSC) thermograms exhibited that ACS had some lower gelatinization temperatures and enthalpies than NCS.

Acetylated and native corn starch blend films produced by blown extrusion

Thermoplastic starch (TPS) materials were developed from mixtures of native and acetylated corn starches with glycerol. To optimize the formulations an experimental design for multicomponent mixtures was used and the assayed formulations were determined by statistical software. Blends and pellets humidity content increased with glycerol concentration. Starch destructuration during the extrusion process was studied by thermal analysis. Films presented homogenous structure, rough surfaces and certain stickiness. They presented different properties, related mainly to the differential characteristics of native and acetylated starches and to hydrophilic character of glycerol. Their mechanical behavior indicated that they are a good option as a food packaging materials since TPS films resulted enough resistant to protect the product and flexible to resist moderate deformations. Besides, the use of acetylated starch in the formulations enhanced film resistance and reduced their WVP, despite of its low modification degree. The storage of the films under controlled conditions increased their stiffness, while their flexibility and WVP were reduced. Plasticizer migration towards the matrix surface was observed in stored films. Films resulted stable till aw=0.7 and due to their selective gaseous permeability they are useful to package products susceptible to oxidation or to control vegetable respiration and senescence.

Potassium sorbate controlled release from corn starch films

Active starch films with glycerol and potassium sorbate were obtained by casting. Native and acetylated corn starches, as well as the mixture of them in equal proportions were used and filmogenic suspensions with pH 4.5 were also prepared. Sorbate concentration decreased during film storage due to its oxidative degradation. Active films resulted more yellow and less transparent than films without sorbate. The minimum inhibitory concentration of sorbate resulted 0.3%, regardless of the starch type and the formulation pH. The use of antimicrobial package was more effective to prevent microbial growth on food surfaces than the use of conventional methods. Additive kinetic release was neither affected by the starch type nor by the formulation pH. Sorbate diffusion process was mathematically modeled satisfactorily. Active films were able to inhibit Candida spp., Penicillium spp., S. aureus and Salmonella spp. growth. Active films extended 21% the shelf life of refrigerated cheese, regardless of the formulation pH.