Pure Starch Films Research Articles

Fabrication of debranched starch nanoparticles via reverse emulsification for improvement of functional properties of corn starch films

In this study, we present a simple and novel method for preparing debranched starch nanoparticles (DSNPs) via reverse emulsification by using waxy corn starch (WCS) as the raw material. The morphology and physicochemical properties of DSNPs were systematically investigated by dynamic light scattering, atomic force microscopy, transmission electron microscopy, X-ray diffraction, and differential scanning calorimetry. In contrast to the microscale range of native WCS, the average particle sizes of DSNPs were mainly in the nanoscale range of 130 nm–280 nm, and showed good monodispersity. All DSNPs samples showed a B + V-type crystalline structure, which is quite different from the A-type of WCS. Furthermore, the relative crystallinity of DSNPs increased from 39.8% to 57.4%. Compared with pure corn starch films, the tensile strength of nanocomposite films increased by 85.9% when the additive amount of DSNPs varied from 0 to 5%. In addition, water vapor permeability and oxygen transmission rate decreased by 30.94% and 79.31%, respectively. The new approach of synthesis starch nanoparticles by reverse emulsification will advance the research of carbohydrate nanoparticles.

Biodegradability and disintegration of multilayer starch films with electrospun PCL fibres encapsulating carvacrol

The biodegradation and disintegration of thermoplastic starch multilayers containing carvacrol(CA)-loaded poly-(ε-caprolactone) electrospun mats were evaluated under thermophilic composting conditions for 45 and 84 days, respectively, and compared with non-loaded carvacrol films and pure starch films. Sample mass loss, thermogravimetric and visual analyses were performed throughout the disintegration test. The disintegration behaviour of all multilayers was similar, reaching values of 75–80% after 84 days. Biodegradation, assessed by carbon dioxide measurements, revealed that all the carvacrol-free films completely biodegraded after 25 composting days. However, the presence of CA notably affected the compost inoculum activity, thus limiting the biodegradability of the CA-loaded multilayers to a maximum value of around 85% after 45 days. Nevertheless, this value was close to that established by the standard ISO method to qualify as biodegradable material.

Properties of active starch-based films incorporating a combination of Ag, ZnO and CuO nanoparticles for potential use in food packaging applications

Abstract Starch (St)-based nanocomposite films containing single or a combination of Ag, ZnO and CuO nanoparticles (NPs) were prepared by the solution casting method. Physico-mechanical and antibacterial properties of the obtained films were investigated. The results indicated that St-ZnO film had higher tensile strength than those of St/Ag and St/CuO films at 2 wt.% of each NPs. Moreover, the film containing a combination of Ag-ZnO-Cuo NPs showed a higher tensile strength and Young’s modulus than those of St/Ag film. Elongation at break % of the control (pure starch) film was the highest followed by St-Ag, St-CuO, St-ZnO, and St-Ag-ZnO-CuO nanocomposite films. The results showed that St-ZnO-CuO-Ag film with 0.667 wt.% of each NPs as well as St-ZnO (3%) film had the lowest solubility in water. The ultraviolet spectroscopy revealed that the St-ZnO film had the highest UV absorbance. Microbial tests showed that St-Ag and St-CuO films had the highest antibacterial activity against E. coli and S. aureus, respectively. With increasing NPs concentration from 1 to 3 wt.% this effect was more enhanced. We found that combinatorial use of Ag/ZnO/CuO NPs in the formulation of starch-based films exhibit synergistic effect in enhancing the antimicrobial and mechanical properties of the resulting films. This would have an important impact in the development of antimicrobial films aiming to reduce the required does of individual metallic NPs.

Characterization and properties of cellulose microfibers from water hyacinth filled sago starch biocomposites

The cellulose microfibers (CMF) from water hyacinth (WH) fiber as a filler in sago starch (SS) biocomposites was investigated. The CMF was isolated by pulping, bleaching and acid hydrolysis methods. The addition of CMF in sago matrix was varied i.e. 0, 5, 10, 15 and 20 wt%. Biocomposites were made by using solution casting and glycerol as a plasticizer. The biocomposites were also determined by tensile test, FTIR, X-Ray, thermogravimetric, SEM, and soil burial tests. The results show that the SS15CMF sample has the highest tensile strength of 10.23 MPa than those other samples. Scanning Electron Microscope (SEM) images show that the strong interaction was formed between CMF WH and matrix. Fourier Transform Infra-red (FTIR) indicated that the functional group of biocomposites was a hydrophilic cluster. The addition of CMF WH in sago starch biocomposites lead to the moisture barrier, crystallinity, and thermal stability increased; it is due to the pure sago starch film was more rapidly degraded than its biocomposites.

Improvement of Thermal Stability of Cassava Starch Films from the Incorparation of Bentonite Clay

This study considered the effect of modified and unmodified bentonite clay on the thermal properties of films based on cassava starch. The bentonite clay was modified in the presence of cetyl trimethyl ammonium bromide (CTAB). The attainment of exfoliated or intercalated nanocomposite was characterized by X-ray diffraction (XRD) and Fourier transform by infrared radiation (FTIR). In XRD, it was verified that the cassava starch dispersed the modified clay in an exfoliated way and unmodified clay in an intercalated way. In the FTIR it was characterized that the cassava starch interacted more with the modified bentonite clay compared to unmodified. Finally, thermogravimetric curves showed the thermal property of the starch films concluding that the modified clay was the reinforcing material that contributed the most to the thermal stability of the cassava starch film, retarding its decomposition point, around 35oC , in relation to the pure starch film.

Using grafted poly(ε-caprolactone) for the compatibilization of thermoplastic starch-polylactic acid blends

Thermoplastic starch (S) and polylactic acid (PLA) blend films were obtained by melt blending and compression moulding using grafted polycaprolactone with maleic anhydride and/or glycidyl methacrylate (PCLMG or PCLG) as compatibilizers. The effect of both the PLA ratio in the blend (20 and 40% with respect to starch) and the amount of both compatibilizers (2.5 and 5%) on the film properties was analysed. Compatibilized blends presented a better dispersion of the PLA in the continuous starch phase, but the use of PCLG provoked a phase inversion in the matrix when 40% of the starch was substituted by PLA. The compatibilized blend films exhibited higher values of elastic modulus than pure starch films, but were less extensible. The use of compatibilizers did not affect the film's water vapour permeability, which was reduced by up to 33 or 50% for 20 and 40% PLA, respectively, although inverted films with 40% PLA and 5% PCLG, exhibited marked reduction (67%). Compatibilizers decreased the oxygen permeability of the films by about 50%, regardless of the ratio of PLA and the kind and amount of compatibilizer. Therefore, substituting 20% of the starch by PLA and incorporating 5% of PCLG would be a good strategy to obtain films useful for food packaging.

Films based on cassava starch reinforced with soybean hulls or microcrystalline cellulose from soybean hulls

Abstract The objectives of this work were to produce films based on cassava starch reinforced with soybean hulls (SH) or microcrystalline cellulose (MCC) obtained from SH by reactive extrusion. The SH and MCC were used at different concentrations (0, 2.5, and 5.0% w/w), and glycerol (25–30 % w/w) was used as a plasticizer to obtain films by extrusion. The addition of 2.5% SH and MCC led to films with lower solubility, water vapor permeability and hygroscopicity than pure starch film, and incorporation of 2.5% MCC improved the film flexibility. The addition of 5% fiber (SH or MCC) resulted in more brittle and hygroscopic films. The incorporation of 2.5% SH and MCC generated films with better performance than that of pure starch ones, and this combination could be a strategy to obtain extruded films with a fully renewable source of polymeric matrix composed mainly of starch.

Preparation of Borax Cross-Linked Starch Nanoparticles for Improvement of Mechanical Properties of Maize Starch Films.

Recently, starch nanoparticles have attracted widespread attention from various fields. In this study, a new strategy for preparing covalent-cross-linked starch nanoparticles was developed using boron ester bonds formed between debranched starch (DBS) and borax. The nanoparticles were characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), X-ray diffraction (XRD), dynamic light scattering (DLS), differential scanning calorimeter (DSC), and thermogravimetric analysis (TGA). The obtained nanoparticles were spherical with a size of 100-200 nm. The formation of boron ester bonds was confirmed by FTIR. The as-prepared starch nanoparticle exhibited a low relative crystallinity of 13.6%-23.5%. Compared with pure starch film, the tensile strength of starch film with 10% starch nanoparticles increased about 45%, and the elongation at break percentage of starch film with 5% starch nanoparticles increased about 20%. The new strategy of forming starch nanoparticles by using boron ester bonds will advance the research of carbohydrate nanoparticles.

Production of active film based on potato starch containing Zedo gum and essential oil of Salvia officinalis and study of physical, mechanical, and antioxidant properties

In this study, biodegradable/antioxidant active film based on potato starch was provided. Composite films of potato starch/Zedo gum/ Salvia officinalis essential oil were provided in different percents of Zedo gum (0.5–1.5%) and S. officinalis essential oil (0–500 µl). The characters of composite film, including physical, mechanical, and antioxidant properties were studied. The results showed that adding different amounts of Zedo gum and essential oil to starch film causes a significant decrease ( p < 0.05) in moisture content, solubility, and film water vapor permeability (WVP). The film containing 1.5% gum and 500 µl of essential oil had minimum moisture content, solubility, and WVP. Results showed that the addition of Zedo gum significantly increased the thickness and opacity of the films and reduced the transparency of the films. Increasing the essential oil is significant on the film opacity and leads to a decrease in the passage of light from the films. By adding different amounts of gum, the antioxidant content of the films was significantly increased compared to the control film (pure starch film). Also, increasing the concentration of essential oil in the film composition caused a significant increase in the antioxidant activity of the films ( p < 0.05). Modified starch films containing 1.5% gum (without essential oil) with 62.64% antioxidant activity and film with 1.5% gum and 500 µl essential oils with 68.35% antioxidant activity had the highest antioxidant activity. The addition of salvia essential oil and Zedo gum significantly decreased the elongation and tensile strength of the potato starch film ( p < 0.05). Finally, the potato starch composite film containing Zedo gum and salvia essential oil showed excellent physical and antioxidant properties and had an excellent ability to be used in the food packaging industry.

THE EFFECT OF OXIDATION ON SAGO STARCH AND ITS APPLICATION AS EDIBLE FILM

THE EFFECT OF OXIDATION ON SAGO STARCH AND ITS APPLICATION AS EDIBLE FILM. The oxidation reaction with hydrogen peroxide in sago starch can influence the proximate test value, physicochemical properties and edible film properties. The hydrogen peroxide formula for starch modifica- tion is 1, 2, 3 and 4%. The presence of hydrogen peroxide increases the physicochemical properties of sago starch so that the quality of modified sago starch is better than pure sago starch. Glycerol is used to improve film flexibility in the manufacture of edible coatings. The characterization of edible film includes water content, contact angle and elongation. Edible film from modified sago starch shows lower water content compared to pure sago starch films. The oxidation effect of H2O2 on edible film results in changes in the hydrophilic properties including the contact angle. Edible film of pure sago starch shows a lower contact angle value. The hydrophilic nature of edible film decreases in the presence of hydrogen peroxide. The high hydrophobicity of the modified sago starch film is caused by the role of carboxyl groups in the starch molecule chain.

Development and characterization of edible films based on eggplant flour and corn starch

In this study, biodegradable and edible films based on eggplant flour (EF) and corn starch (CS) were prepared using casting method at proportion of 0–100, 25–75, 50–50, 75–25 and 100–0%, w/w. The mechanical, barrier, physical, and biodegradability properties were evaluated. Tensile strength, elongation at break, Young's modulus, thickness, density and L⁎ parameter of pure starch films were higher than those of other films. Solubility, water vapor permeability (WVP), moisture content and swelling index of films were augmented with the substitution of CS by EF. Color measurement of the edible films indicated that increasing the proportion of EF increased a⁎, b⁎ and opacity values. The highest amount of water sorption was obtained for pure EF films. Moreover, the incorporation of EF accelerated films biodegradability compared to ones with only starch. In general, EF is a promising material for the formulation of edible and biodegradable films with adequate physical properties for food applications by direct contact.

New Composite Biopolymer with Conductive Properties Obtained from Cassava and Poly Starch (3, 4-Ethylenedioxythiophene)

Objectives: To use of cassava (Manihot esculenta Crantz) starch to prepare a new composite biopolymer from starch and poly (3,4-ethylenedioxythiophene) starch/PEDOT with conducting properties and redox activity. Methods/Analysis: The synthesis of the composite biopolymer starch/PEDOT was carried out by thermochemical process. Its electrochemical properties were studied by means of cyclic voltammetry and the structural characteristics were determined with infrared spectroscopy. Findings: The results showed excellent redox behavior of the composite biopolymer starch/PEDOT, with oxidation and reduction of the polymer at 0.38 V and - 0.43 V potential, respectively. In addition, the kinetic of the composite biopolymer films shows to be faster and more sensitive response that the pure starch and pure PEDOT films. Moreover, a study was conducted with infrared spectroscopy to determine possible interactions or structural changes in the polymer chains of starch when combined with PEDOT. The results of these studies showed that there is an interaction between the molecules of both polymers and an improvement in the conductivity of the starch polymer. Novelty/Improvement: In this way, a composite conductive biopolymer stable from cassava starch and PEDOT was obtained, which has excellent electrochemical properties, which makes it a material with technological potential in chemical sensor or charge storage. Keywords: Composite Biopolymer, Conducting Polymer, Cassava Starch, Electrochemistry, Poly (3, 4-etilendioxitiofeno)

Release of polyphenols from starch-chitosan based films containing thyme extract

The release kinetics of thyme extract polyphenols (TE) from chitosan (CH), pea starch (S) and CH:S blend films in different solvents was evaluated, as well as their antioxidant activity in each release media. Pure starch films showed the fastest delivery rate and the highest delivery ratio of polyphenols, although the corresponding release media exhibited the lowest antioxidant capacity. TE provided CH based films with remarkable antioxidant activity, despite the lower polyphenol release obtained in all solvents, due to the strong polyphenols-chitosan interactions. The maximum amount of polyphenols delivered was found in the acetic acid solution, due to the high solubility of CH. The incorporation of tannic acid (TA) into CH films promoted cross-linking effect, which delays the TE release rate in water and ethanol aqueous solutions, except for CH:S:TA films. Thus, the polarity of the solvents and the polyphenols-matrix interactions markedly affected the polyphenol release and the antioxidant activity of the films.

Effects of chitin nano-whiskers on the antibacterial and physicochemical properties of maize starch films

We investigated the effects of chitin nano-whiskers (CNWs) on the antibacterial and physiochemical properties of maize starch–based films. The microstructures, crystalline structures, and thermal, mechanical and barrier properties of the nanocomposite films were characterized by using transmission electron microscopy, X-ray diffraction analysis, thermogravimetric, differential scanning calorimeter, and texture profile analysis. The tensile strength of the maize starch films increased from 1.64MPa to 3.69MPa (P<0.05) after CNW reinforcement with up to 1%. The water vapor permeability of the nanocomposite films decreased from 5.32×10−12 to 2.22×10−12gm−1s−1Pa−1 with the CNW content increasing from 0% to 2%. The onset temperature, peak temperature and the gelatinization enthalpy of the films containing CNWs were higher than those of the pure starch films. Furthermore, the nanocomposite films exhibited strong antimicrobial activity against Gram-positive Listeria monocytogenes but not against Gram-negative Escherichia coli.

A Kinetics Study on the Thermal Degradation of Starch/Poly (Vinyl Alcohol) Blend

The thermal degradation of starch/poly (vinyl alcohol) (PVA) blend was studied by using TG in air atmosphere. Thermo-analytic investigations on pure starch film and starch/PVA blend film were carried out to evaluate the thermal stability and the respective activation energy of the materials. Experiments in air atmosphere and under non-isothermal and isothermal condition carried out. The Kissinger and Flynn-Wall-Ozawa methods were used to calculate the activation energy of non-isothermal degradation of starch and starch/PVA blends. The results show that these two methods were suitable and effective to describe the thermal degradation of starch and starch/PVA blends. These results are shown that starch/PVA blend was thermally less stable than pure starch and thermal stability of films decreased with increasing PVA content.

Characterization of edible corn starch nanocomposite films: The effect of self‐assembled starch nanoparticles

Corn starch nanocomposite films with varying concentrations (0–25%) of starch nanoparticles (SNPs) were obtained with the solution casting method. The scanning electron microscopy images, crystalline characteristics, transparency, water vapor permeability, mechanical properties, and thermal behavior of the nanocomposite films were evaluated. The results showed that when incorporated SNPs from 0 to 15% in the films, the water vapor permeability decreased from 5.89 × 10−12to 3.08 × 10−12 g/m s Pa, and the tensile strength significantly improved from 1.40 to 2.35MPs. Scanning electron microscopy (SEM) revealed that the film surfaces were rougher than those of the pure starch films. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) showed that the thermal stability of the nanocomposite films increased. A slight change in the crystalline structure of the nanocomposite films was observed in the X‐ray diffraction (XRD) pattern, due to the SNPs. Our research suggested that SNPs have a favorable effect on the properties of corn starch films, which would helpful in applications as biodegradable packaging material.

Composite materials derived from biodegradable starch polymer and Atriplex halimus fibers

AbstractBiocomposites from starch and cellulose fibers have gained renewed interest as environmentally friendly materials and as biodegradable renewable resources for a sustainable development. In this study, natural fibers were extracted from a Mediterranean saltbush (Atriplex halimus) plant found abundantly in North Africa. The composites were prepared by a solution casting method from corn starch using 0–15 wt.% of micro-cellulose fibers as a filler. The structure of the composites was investigated by Fourier transform infrared spectroscopy. The physical properties of the composites were determined by mechanical tensile tests, thermogravimetric analysis and water absorption. The results showed that higher fiber content raised the elastic modulus by 92% and the temperature of degradation by up to 355°C. Optical microscopy revealed a good adhesion between the matrix and the fibers owing to their chemical similarities. Water uptake measurements showed that the composites had a much better water resistance and a more hydrophobic character than pure thermoplastic starch films. Biodegradability tests confirmed that the prepared composites are an environmentally safe material suited for different applications.

Starch‐MMT composite films: Effects of bio‐inspired modification on MMT

Montmorillonite (MMT) was modified by bio‐inspired polydopamine (PDA) to obtain an exfoliated structure. Then, the modified MMT (MMT‐D) and the original MMT were incorporated into starch to fabricate individual composite films. MMT lamellae were mostly intercalated in starch, while those of MMT‐D were more likely to be exfoliated and presented better dispersibility, as revealed by the surface morphologies and XRD patterns of the composite films. Although MMT provided greater thermal protection to starch, MMT‐D improved the tensile properties of the composite films more effectively. The composite film containing 2% MMT‐D displayed a tensile strength as high as 8.1 MPa and a Young's modulus as high as 416.4 MPa, which were 2.1 and 3.8 times the values of the pure starch film, respectively. However, the composite films containing MMT had reduced tensile strength and modulus. This study showed that PDA pre‐modification of MMT could improve the performance of starch‐based nanocomposites, thus accelerating their acceptance in food packaging applications.

Characterisation of corn starch-based films reinforced with taro starch nanoparticles

Taro starch nanoparticles (TSNPs) obtained by hydrolysis with pullulanase and the recrystallisation of gelatinised starch were used as reinforcing agents in corn starch films. The influence of TSNPs contents (0.5–15%) on the physical, mechanical, thermal, and structural properties of starch films was investigated. An increase in the concentration of TSNPs led to a significant decrease in the water vapour permeability (WVP) of films. The addition of TSNPs increased the tensile strength (TS) of films from 1.11MPa to 2.87MPa. Compared with pure starch films, the surfaces of nanocomposite films became uneven. The onset temperature (To) and melting temperature (Tm) of films containing TSNPs were higher than those of pure starch films. The addition of TSNPs improved the thermal stability of starch films.

Characterisation of composite edible films based on wheat starch and whey‐protein isolate

SummaryComposite films prepared by casting wheat starch and whey‐protein isolate at proportions of 100–0%, 75–25%, 50–50%, 25–75% and 0–100% were characterised. Combination of both substances gave continuous and homogeneous films. The more the starch is in a film, the more dull is the appearance. The highest water adsorption was observed for pure whey‐protein films and the lowest for pure wheat starch films with the final water content of 0.264 and 0.324 g water g d.m.−1, respectively. An exponential equation well fitted the experimental data of water vapour kinetics (R2 ≥ 0.99). The highest values of thickness and elongation at break were observed for films obtained by blending of wheat starch and whey protein. With the increasing content of whey‐protein isolate, the values of the swelling index and tensile strength increased from 34.31% to 71.01% and from 2.29 to 8.90 MPa, respectively. The values of water vapour permeability depended on humidity conditions and decreased slightly with the increasing content of whey‐protein isolate.