PhD student , RMIT University
A biodegradable composites material with improved mechanical and physical properties for packaging.
Environmental and legislative pressure has driven industry to develop waterborne and biodegradable polymer composites. Hence, the interest in developing composites of polymers that are dispersible in water and are biodegradable is increasing due to their biodegradable nature and other desirable properties. Such composites are expected to facilitate the tailoring or designing of materials to meet the requirement of specific end users. This project aims to develop novel ionic functionalized polyurethane (FPU) and investigate the effect of FPU structure on starch properties. Starch are chosen as the polysaccharide component of the FPU-polysaccharide composite as they are biodegradable and biocompatible. PUs are well known for their excellent biocompatibility, mechanical properties and approved by FDA regulation for biomedical, pharmaceutical and food application.
Most of research to date in developing starch-PU composite materials has used starch as a filler material to provide reinforcement to composite. Yet, a well dispersed starch-PU composite contains up to 20 % w/w starch, above which phase separation occurs which leads to poor mechanical.
We have successful developed a flexible starch-FPU films with improved hydrophobicity and physical properties. It is possible to mix FPU with starch to enhance the performance the thermoplastic starch. This is because both FPU and starch contain hydrophilic groups (anionic/ cationic urethane and hydroxyl group). The hydrophilic groups in both starch and PU show potential miscibility which makes it possible to incorporate FPU into starch. Ionic polyurethane have reported to have improved compatible systems, due to coulombic forces between ionic PUI create more entanglements between the polymeric chains of the ionomers and the blending materials. Incorporating certain optimal concentration of FPU into starch matrix enhances the performance of the said FPU/starch composite in terms of mechanical properties (higher tensile strength and higher elongation at break) and improves hydrophobicity of the resultant starch-FPU composite films.
Abstract: Acid‐converted cornstarch was subjected to a pretreatment of cationization using N‐(3‐chloro‐2‐hydroxypropyl) trimethylammonium chloride to introduce 3‐(trimethylammonium chloride)‐2‐hydroxypropyl (TMACHP) substituents onto starch chains. Then, the quaternized starch was further modified via a graft copolymerization of the starch with acrylic acid in aqueous medium using Fe2+‐H2O2 initiator. The investigation was carried out to reveal the influence of TMACHP substituents on the graft copolymerization and sizing properties. The graft copolymerization was evaluated with grafting efficiency, grafting ratio, and conversion of monomer to polymer while the sizing properties considered included paste viscosity, adhesions to fibers, film performances, mechanical properties of sized yarns, and desizability. It was found that the TMACHP substituents introduced was able to increase the grafting efficiency and ratio of the copolymerization. In addition, the quaternized starch‐g‐poly(acrylic acid) (QS‐g‐PAA) was superior to starch‐g‐poly(acrylic acid) (S‐g‐PAA) in the adhesions. The cationization was capable of toughening starch film due to significant increase in breaking elongation, work‐to‐break, and bending endurance of the film. Moreover, the mechanical properties of the yarns sized with QS‐g‐PAA were better than those with S‐g‐PAA. Furthermore, the QS‐g‐PAA was stable in paste viscosity and desizable from sized yarns. A low level of the quaternization could be adopted to improve the grafting efficiency and sizing properties.
Pub.: 22 Feb '16, Pinned: 26 Aug '17
Abstract: White shrimps (Litopenaeus vannamei) are a major aquaculture product in the world fishery market. The main aim of this study was to investigate the effect of clove‐ and cinnamon‐assimilated starch edible films on the shelf life of white shrimps in terms of maintaining their freshness and other organoleptic properties. Physical, chemical, microbial and sensory qualities of edible film‐wrapped white shrimps were studied until they reached their limit of acceptability during storage at different temperatures (10 and 4 °C).Shrimp samples wrapped with spice‐assimilated edible films showed lower bacterial counts. Shelf life extension of edible film‐wrapped white shrimps was estimated to be 14 and 12 days for storage at 10 and 4 °C respectively. Reduced lipid oxidation and release of nitrogen base compounds were noted for edible film‐wrapped shrimp samples. Good consumer acceptance was noted for edible film‐wrapped shrimp samples through sensory evaluation.The results of this study show that spice‐fused edible films were effective in inhibiting the growth of microbial populations. Reductions in lipid oxidation and total volatile base nitrogen were also achieved through edible film wrapping of shrimps, which increased their consumer acceptance during sensory evaluation. © 2016 Society of Chemical Industry
Pub.: 26 Feb '16, Pinned: 26 Aug '17
Abstract: Fully biobased edible films were prepared using native potato starch plasticized with glycerol and further reinforced with catechin (Cat) and starch nanocrystals (SNC) obtained by acidic hydrolysis from waxy maize starch granules. The thermal stability of starch nanocrystals obtained at different pH was studied, resulting on a decreasing in thermal stability at higher pH values. The X-ray diffraction patterns of the plasticized reinforced materials display complete destructuration of starch by solvent casting process. Plasticized films showed lower onset degradation temperatures than non-plasticized starch film. The reduction of the inter- and intra-molecular bonds interaction within the polymer matrix due to glycerol presence leads to a decrease of the thermal stability of the whole system. On the other hand, Cat and SNC produced an increase on the thermal stability of the bionanocomposites delaying the beginning of the thermal decomposition of starch/glycerol systems of about 20 °C. The mechanical performance was also improved in the ternary bionanocomposite edible films. All the edible films were fully disintegrated in compost conditions suggesting their possible applications as biodegradable edible films for packaging.
Pub.: 27 Feb '16, Pinned: 26 Aug '17
Abstract: In this study, composite films of corn starch, methylcellulose and carboxymethylcellulose plasticized by glycerol or polyethylene glycol (PEG) were prepared and the effects of blending level as well as the plasticizer type on the microstructure, water vapor permeability (WVP), opacity and solubility properties were investigated. Scanning electron Microscopy (SEM) observations showed homogeneous matrix of glycerol plasticized films and it was taken as an indicator of structural integrity. PEG plasticized films exhibited discontinuous surface, and this was attributed to phase separation. WVP of the films was found between 1.5 × 10−11 and 13.3 × 10−11 g/s m Pa and composite films were more resistant to water than starch film. However, WVP values were significantly higher than many of the synthetic films; as a result, one of the potential applications for presented films might be utility as a hydrophilic polymer layer in active food packaging applications. Among the factors studied, the plasticizer type was the most effective factor on the opacity of the films. Besides, differences in solubility were attributed to the differences in their structural integrity.Starch films have good barrier properties to oxygen, carbon dioxide and lipids; however, they have limited mechanical properties and water vapor resistance. In the presented study, this problem is overcome by blending with cellulose ethers and water resistance is improved up to six folds. The developed films are in hydrophilic character when compared to conventional synthetic films such as PE and PP. Therefore, the developed films are quite appropriate to be used as a carrier polymer matrix for active hydrophilic and/or volatile compounds in active food packaging applications. Another potential applications of those films presented in this study is utilization as edible film layer where mechanical and permeability resistance needed.
Pub.: 22 Mar '16, Pinned: 26 Aug '17
Abstract: Fabrication of starch-based edible film using blown film extrusion is challenging and interesting because this process provides continuous operation with shorter production time and lower energy consumption, is less labor intensive, and results in higher productivity than the conventional solution casting technique. Previously, we reported on the preparation and some properties of thermoplastic starch/chitosan (TPS/CTS) blown films; however, their morphological characteristics and barrier properties had not yet been elucidated. The present work thus aims to investigate the effect of chitosan (0.37–1.45%) on morphological characteristics, water vapor and oxygen barrier properties as well as hydrophilicity of the TPS and TPS/CTS films. The relationship between morphological characteristics and properties of the films was also discussed. Scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM) and X-ray photoelectron spectroscopy (XPS) confirmed the distribution and deposition of chitosan on the film surface. The existence of chitosan on the surface imparted the improved water vapor and oxygen barrier properties and the reduced surface hydrophilicity to the film. The results suggest that this biodegradable bio-based TPS/CTS film could potentially be used as an edible film for food and pharmaceutical applications.
Pub.: 28 Apr '16, Pinned: 26 Aug '17
Abstract: In this research, potato starch and TiO2 nanoparticles (0.5, 1 and 2 weight %) films were developed. Influences of different concentrations of TiO2 on the functional properties of nanocomposite films (water-related properties, mechanical characteristics, and UV transmittance) were investigated. XRD, FTIR, and DSC analyses were used to characterize the morphology and thermal properties of the films. The results revealed that TiO2 nanoparticles dramatically decreased the values of water-related properties (water vapor permeability: 11-34%; water solubility: 1.88-9.26%; moisture uptake: 2.15-11.18%). Incorporation of TiO2 led to a slight increment of contact angle and tensile strength, and a decrease in elongation at break of the films. TiO2 successfully blocked more than 90% of UV light, while opacity and white index of the films were enhanced. Glass transition temperature and melting point of the films were positively affected by the addition of TiO2 nanoparticles. The result of XRD study exhibited that due to a limited agglomeration of TiO2 nanoparticles, the mean crystal size of TiO2 increased. Formation of new hydrogen bonds between the hydroxyl groups of starch and nanoparticles was confirmed by FTIR spectroscopy. In conclusion, TiO2 nanoparticles improved the functional properties of potato starch film and extended the potential for food packaging applications.
Pub.: 28 Apr '16, Pinned: 26 Aug '17
Abstract: The moisture sorption isotherm of pea starch films prepared with various glycerol contents as plasticizer was investigated at different storage relative humidities (11%–96% RH) and at 5 ± 1, 15 ± 1, 25 ± 1 and 40 ± 1 °C by using gravimetric method. The results showed that the equilibrium moisture content of all films increased substantially above aw = 0.6. Films plasticized with glycerol, under all temperatures and RH conditions (11%–96%), adsorbed more moisture resulting in higher equilibrium moisture contents. Reduction of the temperature enhanced the equilibrium moisture content and monolayer water of the films. The obtained experimental data were fitted to different models including two-parameter equations (Oswin, Henderson, Brunauer–Emmitt–Teller (BET), Flory–Huggins, and Iglesias–Chirife), three-parameter equations Guggenhiem–Anderson–deBoer (GAB), Ferro–Fontan, and Lewicki) and a four-parameter equation (Peleg). The three-parameter Lewicki model was found to be the best-fitted model for representing the experimental data within the studied temperatures and whole range of relative humidities (11%–98%). Addition of glycerol increased the net isosteric heat of moisture sorption of pea starch film. The results provide important information with estimating of stability and functional characteristics of the films in various environments.
Pub.: 24 Dec '15, Pinned: 26 Aug '17
Abstract: The use of plastic film in agriculture has the serious drawback of producing vast quantities of waste. In this work, films were prepared from natural fibers and biodegradable polymers as potential substitutes for the conventional non-biodegradable plastic film used as mulching material in agricultural production. The physical properties (e.g., mechanical properties, heat preservation, water permeability, and photopermeability) and degradation characteristics (evaluated by micro-organic culture testing and soil burial testing) of the films were studied in both laboratory and field tests. The experimental results indicated that these fiber/polymer films exhibited favorable physical properties that were sufficient for use in mulching film applications. Moreover, the degradation degree of the three tested films decreased in the following order: fiber/starch (ST) film > fiber/poly(vinyl alcohol) (PVA) film > fiber/polyacrylate (PA) film. The fiber/starch and fiber/PVA films were made from completely biodegradable materials and demonstrated the potential to substitute non-biodegradable films.
Pub.: 12 May '16, Pinned: 26 Aug '17
Abstract: To identify the significant contribution of intermolecular hydrogen bonds of starch molecules to the film structure formation, pH of film‐forming solutions was adjusted and also various salts (NaCl, CaCl2, CaSO4, and K2SO4) were mixed into the glycerol‐plasticized pea starch film. The film made from pH 7 possessed the highest tensile strength‐at‐break (2 times) and elastic modulus (4 to 15 times) and the lowest elongation‐at‐break compared with those of the films made from acid and alkali environments. The pH 7 film also has the highest film density and the lowest total soluble matter. At the level of 0.01 to 0.1 M of CaSO4 and 0.1 M of K2SO4 in a kilogram of starch, the water solubility of the film increased, while chloride salts slightly lowered the solubility. NaCl and CaSO4 reduced water vapor permeability (WVP), while CaCl2 slightly increased WVP at 0.01 and 0.06 M concentrations, and K2SO4 significantly increased WVP at 0.03 and 0.15 M. Presence of salts increased tensile strength (5 to 14 times than the control films) and elastic modulus (35 to 180 times) of starch film at 0.01 to 0.03 M of CaSO4 and K2SO4. Elongation‐at‐break increased significantly as salt concentration increases to an optimal level. However, when the concentration exceeded above the optimal level, the E of starch films decreased and showed no significant difference from the control film. Overall, the addition of salts modified physical and mechanical properties of pea starch films more than pH adjustment without any salt addition.High amylose starch is a naturally made linear polymer and has a great potential for various polymer applications such as biodegradable plastics, edible coatings/films, a delivery matrix for flavors, nutraceuticals, and pharmaceuticals. By altering pH and including various salts, the mechanical and physical properties of the starch films were modified to be more suitable for the industrial applications. These treatments can improve the process applicability and material suitability of starch films without complicated R&D processes required cost and high technology for food and pharmaceutical industry.
Pub.: 31 May '16, Pinned: 26 Aug '17
Abstract: The mechanical properties and moisture sorption at relative humidity (RH) range of 11–94%, water vapor permeability (WVP), solubility in water and color of the pea starch films as a function of glycerol were examined. The results showed that increasing the concentration of plasticizer resulted in improvement of the tensile strength of the films at RH <43%, the percent elongation as well as the deformation at break at RH <84%. Increasing plasticizer content and RH also resulted in films with lower Young's modulus, lower puncture force, but higher puncture deformation. Furthermore, increasing plasticizer content led to the films with more opaque appearance. Films prepared with 15 and 25% glycerol had lower WVP in comparison with unplasticized film. This study provides information regarding the advantageous or disadvantageous of possible application of pea starch films in food packaging industry.Starch edible films have been utilized for packaging technologies and edible coatings. Pea starch has been found to produce the films with improved physical and mechanical properties in comparison with films prepared from other starches due to high amount of amylose. The development of pea starch film with improved functions affects its application. Pea starch edible films may find practical applications in the poultry, meat, seafood, fruit, vegetable, grains and candies industries.
Pub.: 01 May '16, Pinned: 26 Aug '17
Abstract: The present study investigated the effects of plasticizers (fructose, urea, tri‐ethylene glycol, and triethanolamine) with different concentrations on the physical, thermal, and mechanical properties of cassava‐starch‐based films. The film samples were prepared using casting methods. The moisture content, water solubility, and water absorption of the films increased with increasing plasticizer content. Fructose‐plasticized films show excellent water resistance compared to other plasticizers. Film plasticized with 30% fructose showed the highest density (1.74 g/cm3), but the lowest water content (10.96%) and water absorption (110%). Films containing fructose presented smooth surfaces without pores. The glass transition temperatures of the plasticized film also decreased with increased plasticizer content, irrespective of the plasticizer type. The relative crystallinity decreased with increasing plasticizer content. The film plasticized by 30% fructose presented higher relative crystallinity (0.31). The increase of plasticizer concentration resulted in a decrease of tensile strength, but increased elongation at break of the film samples. Film plasticized with 30% fructose showed the highest tensile strength (4.7 MPa) and tensile modulus (69 MPa). Thus, fructose was the most efficient plasticizer agent among the various plasticizers used in this study. High contents of plasticizer resulted in changes in the properties of the films. Overall, it can be concluded that the plasticizer type and concentration significantly influence the properties of cassava‐starch‐based film.
Pub.: 02 Jun '16, Pinned: 26 Aug '17
Abstract: Barley husk (BH) was graft copolymerized by palmitic acid. The crystalline behavior of BH decreased after grafting. Poly vinyl alcohol (PVA)/starch (St) blend film, urea formaldehyde cross linked PVA/St films and composite films containing natural BH, grafted BH were prepared separately. The effect of urea/starch ratio, content of BH and grafted BH on the mechanical properties, water uptake (%), and biodegradability of the composite films was observed. With increase in urea: starch ratio from 0 to 0.5 in the blend, tensile strength of cross linked film increased by 40.23% compared to the PVA/St film. However, in grafted BH composite film, the tensile strength increased by 72.4% than PVA/St film. The degradation rate of natural BH composite film was faster than PVA/St film. Various films were characterized by SEM, FT-IR and thermal analysis.
Pub.: 09 Jun '16, Pinned: 26 Aug '17
Abstract: Native and modified starches have received considerable attention for biodegradable films formulation due to their completely biodegradable nature, edible characteristics, and low cost. Development and characterization of starch films obtained by: (i) casting, (ii) blown extrusion and (iii) the thermo‐compression moulding process are described. The rheological properties of filmogenic suspensions, the barrier properties, and the mechanical resistance of the obtained films are reported. Addition of specific additives to the formulations modifies the film functionality transforming them into active materials. Diffusion of antimicrobial agents such as potassium sorbate from the active starch film, as well as their efficacy in dairy products is discussed. Likewise, reinforcing agents lead to composite materials with improved mechanical resistance. Starch‐based materials show higher permeability to carbon dioxide than to oxygen, which is useful to control the respiration rate of fruits and vegetables. The application of active starch‐based coatings to strawberries and Brussels sprouts in order to prolong their refrigerated storage life is analyzed. A detailed overview on the formulation and performance of starch‐based films employing industrial and lab‐scale methods, as well as the application of starch coatings to improve food quality is presented, with the aim of analyzing the possibility of development and application of such materials.
Pub.: 19 Jun '16, Pinned: 26 Aug '17
Abstract: The structure and property of cassava starch‐based films, produced by using 1‐butyl‐3‐methylimidazolium chloride ([BMIM]Cl) and glycerol as combined plasticizers, were investigated. The combined plasticizers exhibited a stronger effect on the disruption of starch granules compared with glycerol as observed by scanning electron microscopy (SEM). When the mass ratio of [BMIM]Cl/glycerol used was 15/15, all the starch granules were disrupted and transferred to a continuous phase. Due to the strong plasticization effect of [BMIM]Cl, the combined plasticizers contributed to a lower water content, crystallinity, and glass‐transition temperature, as well as a higher flexibility when compared with glycerol. Additionally, in spite of the slight decrease in the elongation at break, the combined plasticizers contributed to a higher thermal stability, higher tensile strength, and a lower cost relative to [BMIM]Cl alone, showing excellent potential for practical applications. Therefore, using [BMIM]Cl and glycerol as combined plasticizers to plasticize starch film is effective, practical, and economical, and opens up a new perspective for the plasticization of starch.
Pub.: 23 Jun '16, Pinned: 26 Aug '17
Abstract: This work revealed the influence of thermal processing on the microstructural, mesoscopic and molecular scale structures and thus the plasticizer migration of the starch ester films. Thermal processing promoted the permeation of water molecules to hinder the shrink of the amorphous macromolecules. That is, the swelling of the amorphous macromolecules diminished the ordered regions to a certain degree, resulting in the enlarged amorphous regions. Along with slight degradation of the macromolecules, the crystallites were partially disorganized, as indicated by a reduced relative crystallinity. These multi-scale structural changes of the films and the thermally enhanced mobility of plasticizer molecules synergistically enhanced the plasticizer migration. This study not only enables a well understanding of how thermal treatment alters the plasticizer migration of starch-based films from a multi-scale structural view, but also hints to our future work that rationally modulating the structural features of starch-based film may effectively control the migration of chemicals.
Pub.: 13 Jul '16, Pinned: 26 Aug '17
Abstract: Nanocomposites are being used as a new type of packaging that has good biodegradability and antibacterial ability and that has wide applicability in the preservation and storage field. Transmission electron microscopy results demonstrated that the AgNPs were spherical in shape with the diameter of 2–6 nm for 48 h reaction time. The mechanical properties of composite films increased after the incorporation of AgNPs. Differential scanning calorimetric and thermogravimetric analysis results showed that the thermal stability of silver–starch composite film was increased through incorporation with AgNPs. The composite films exhibited strong antibacterial activity against Escherichia coli and Staphylococcus aureus, and the composite films were more effective against Gram-negative bacteria (E. coli).
Pub.: 30 Jul '16, Pinned: 26 Aug '17
Abstract: This work compares the effect of adding different biopolyester electrospun coatings made of polycaprolactone (PCL), polylactic acid (PLA) and polyhydroxybutyrate (PHB) on oxygen and water vapour barrier properties of a thermoplastic corn starch (TPCS) film. The morphology of the developed multilayer structures was also examined by Scanning Electron Microscopy (SEM). Results showed a positive linear relationship between the amount of the electrospun coatings deposited onto both sides of the TPCS film and the thickness of the coating. Interestingly, the addition of electrospun biopolyester coatings led to an exponential oxygen and water vapour permeability drop as the amount of the electrospun coating increased. This study demonstrated the versatility of the technology here proposed to tailor the barrier properties of food packaging materials according to the final intended use.
Pub.: 11 Aug '16, Pinned: 26 Aug '17
Abstract: This study investigated the possibility of enhancing the properties of collagen with three different maize starches: waxy maize starch, normal starch, and high amylose starch. Scanning electron microscopy images revealed that starch-collagen films had a rougher surface compared to pure collagen films which became smoother upon heating. Amylose starch and normal starch increased the tensile strength of unheated collagen films in both dry and wet states, while all starches increased tensile strength of collagen film by heating. Depending upon the amylose content and starch concentrations, film solubility in water decreased with the addition of starch. DSC thermograms demonstrated that addition of all starches improved the thermal stability of the collagen film. Moreover, X-ray diffraction results indicated that except for high amylose starch, the crystallinity of both starch and collagen was significantly decreased when subject to heating. FTIR spectra indicated that intermolecular interactions between starch and collagen were enhanced upon heating.
Pub.: 17 Aug '16, Pinned: 26 Aug '17
Abstract: Abstract This work examines the effect of lithium trifluoromethanesulfonate (LiCF3SO3) and glycerol on the conductivity and dielectric properties of potato starch-chitosan blend-based electrolytes. The electrolytes are prepared via solution cast technique. From X-ray diffraction (XRD) analysis, the blend of 50 wt.% starch and 50 wt.% chitosan is found to be the most amorphous blend. Fourier transform infrared (FTIR) spectroscopy studies show the interaction between the electrolyte materials. The room temperature conductivity of pure starch-chitosan film is found to be (2.85 ± 1.31) × 10−10 S cm−1. The incorporation of 45 wt.% LiCF3SO3 increases the conductivity to (7.65 ± 2.27) × 10−5 S cm−1. Further conductivity enhancement up to (1.32 ± 0.35) × 10−3 S cm−1 has been observed on addition of 30 wt.% glycerol. This trend in conductivity is verified by XRD and dielectric analysis. The temperature dependence of conductivity of all electrolytes are Arrhenian.AbstractThis work examines the effect of lithium trifluoromethanesulfonate (LiCF3SO3) and glycerol on the conductivity and dielectric properties of potato starch-chitosan blend-based electrolytes. The electrolytes are prepared via solution cast technique. From X-ray diffraction (XRD) analysis, the blend of 50 wt.% starch and 50 wt.% chitosan is found to be the most amorphous blend. Fourier transform infrared (FTIR) spectroscopy studies show the interaction between the electrolyte materials. The room temperature conductivity of pure starch-chitosan film is found to be (2.85 ± 1.31) × 10−10 S cm−1. The incorporation of 45 wt.% LiCF3SO3 increases the conductivity to (7.65 ± 2.27) × 10−5 S cm−1. Further conductivity enhancement up to (1.32 ± 0.35) × 10−3 S cm−1 has been observed on addition of 30 wt.% glycerol. This trend in conductivity is verified by XRD and dielectric analysis. The temperature dependence of conductivity of all electrolytes are Arrhenian.33−10−133−5−1−3−1
Pub.: 01 Sep '16, Pinned: 26 Aug '17
Abstract: The individual and interactive impacts of guar gum and glycerol on the pea-starch-based edible film characteristics were examined using three factors with three-level Box–Behnken response surface design (BBD). The results showed that density and elongation at break were only significantly (p < 0.05) affected by pea starch and guar gum in a positive linear fashion. The quadratic regression coefficient of pea starch showed a significant effect (p < 0.05) on thickness, density, puncture force, water vapor permeability, and tensile strength, while tensile strength and Young's modulus were affected by the quadratic regression coefficient of glycerol and guar gum, respectively. The results were analyzed using Pareto analysis of variance (ANOVA) and the developed predictive equations for each response variable presented reliable and satisfactory fit with high coefficient of determination (R2) values (≥0.96). The optimized conditions with the goal of maximizing mechanical properties and minimizing water vapor permeability were 2.5 g pea starch, 0.3 g guar gum, and 25% w/w glycerol based on the dry film matter in 100 mL of distilled water.
Pub.: 26 Sep '16, Pinned: 26 Aug '17
Abstract: In order to study the impact of starch in film performance, high amylose corn starch was composited in gelatin films under different gelatinization conditions and, in high and low concentrations (10 and 50 wt.%). It was found that hot water gelatinized starch (Gel-Shw) increased film mechanical strength and was dependent upon the starch concentration. The addition of an alkali component to the starch significantly enhanced the swelling of the starch granules and expedited the gelatinization process. Incorporation of starch, especially the alkalized starch (Sha), into the gelatin films decreased film solubility which improved its water resistance and water vapor permeability (WVP). Multiple techniques (DSC, TGA, FT-IR, and XRD) were used to characterize the process and results, including the crosslinking of the dissolved starch molecules and the particles formed from gelatinized starch during retrogradation process, which played an important role in improving the thermal stability of the composited gelatin films. Overall, the starch-gelatin composition provides a potential approach to improve gelatin film performance and benefit its applications in the food industry.
Pub.: 11 Oct '16, Pinned: 26 Aug '17
Abstract: Biodegradable films from native or acetylated starches with different amylose levels were prepared. The films were characterized according to the mechanical, water vapor barrier, thermal, and biodegradability properties. The films from acetylated high amylose starches had higher moisture content and water solubility than the native high amylose starch film. However, the acetylation did not affect acid solubility of the films, regardless of the amylose content. Films made from high and medium amylose rice starches were obtained; however low amylose rice starches, whether native or acetylated, did not form films with desirable characteristics. The acetylation decreased the tensile strength and increased the elongation of the films. The acetylated starch-based films had a lower decomposition temperature and higher thermal stability than native starch films. Acetylated starches films exhibited more rapid degradation as compared with the native starches films.
Pub.: 31 Oct '16, Pinned: 26 Aug '17
Abstract: Publication date: March 2016 Source:Food Packaging and Shelf Life, Volume 7 Author(s): Aníbal M. Slavutsky, María A. Bertuzzi A nanolaminate consists of two or more layers of material with nanometric dimensions that are physically or chemically bonded to each other. Starch based edible films present suitable characteristics for food protection, but their functional properties are affected by film water content. Nanolaminated films were formulated by coating the starch film with lipid nanolayers in order to improve their water resistance and barrier properties. Lipid nanolayer presence was confirmed by SEM images and contact angle measurements. Sorption isotherms of nanolaminated films showed an important reduction in film water adsorption through all the a w range studied. The effect on permeability of the driving force (a w difference) and the a w values at each side of the film, were analysed. Water vapour transport was controlled by water diffusion through hydrophobic nanolayers. Nanolamination of edible films improved the water barrier properties of hydrophilic films by combining starch with lipids materials at nanometric scale.
Pub.: 11 Feb '16, Pinned: 26 Aug '17
Abstract: A nanocomposite degradable chitosan–rice-starch (CRS) film was prepared by incorporation of commercial (Comm.) and microbial synthesized silver (Ag) and zinc oxide (ZnO) nanoparticles (NPs) using a solvent-casting technique. The prepared films were characterized for thickness, surface color measurement, transparency, presence of crystalline features, surface topography, and surface elemental composition. The fabricated nanocomposite films were evaluated for antimicrobial activity and were observed to curb the growth of test Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) microorganisms in an in vitro media Petri plate study. The screened nanocomposite films were then tested to improve the shelf life of peach fruits (cv. Shan-i-Punjab) in packaging. The nanocomposite films with incorporated NPs decreased the overall surface microbial load and enhanced the shelf life of packed peach fruits as compared to unpackaged and packaged fruits with control film. The lowest percentage loss in weight (4.75%) was recorded in peach fruits packaged with film incorporated with Comm. Ag NPs. The lowest change in diameter (4.25–4.05 cm) and the highest ascorbic acid content (0.51 mg/g) were found in peach fruits packaged with films incorporated with Comm. ZnO NPs. The lowest percent (9.6%) increase in total soluble solids was observed for fruits packaged with films incorporated with Comm. AgNPs. The microbial counts on the surface of the fruit was highest for the unpackaged control treatment and lowest for fruits packaged with Comm. Ag NPs. SEM study of the surface of the peaches showed the presence and adherence of microbial cells (bacteria, yeast, and fungi) on the trichomes and the fruit surface.
Pub.: 03 Jan '17, Pinned: 26 Aug '17
Abstract: Starch is regarded as one of the most promising biopolymers to replace the fossil resources. However, due to the poor mechanical properties, high sensitivity to humidity, and low barrier property, the development of starch-based materials has been limited. In this study, they improved the mechanical and barrier properties of starch film with reduced graphene oxide (RGO) modified by sodium dodecyl benzene sulfonate (SDBS). The hydrophilia of modified RGO (r-RGO) was improved and result in a good dispersion in oxidized starch (OS) matrix. The tensile strength of the r-RGO-4/OS film increased to 58.5 MPa which was more than three times of the OS film (17.2 MPa). Besides, both the water vapor and oxygen barrier properties of r-RGO/OS film were improved greatly compared with OS and GO/OS films. Moreover, the r-RGO/OS film could protect against UV light effectively due to its lightproof performance. In conclusion, the r-RGO/OS composite film has great potential applications in packaging industry. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 133, 44910.
Pub.: 07 Feb '17, Pinned: 26 Aug '17
Abstract: Consumer markets have questioned the use of plastics in packaging because of their environmental impact, and alternative, bio-based films are being developed for this purpose. This study employs Life Cycle Assessment to analyze the environmental and energy performances of producing cassava starch-based film made from casting in Brazil. Results indicate that impacts are mainly caused by the cassava crops, the film manufacture, and the fossil glycerin and ethanol additives used. Resource efficiency and cleaner production measures were devised to reduce the environmental and energy impacts of the product. In terms of energy, an arrangement using both renewable glycerin and biofilm made by extrusion combining cassava starch and polyethylene was shown to be an adequate option to reduce impact. The use of sugarcane ethanol led to an increase in impact for most of the analyzed categories. On the other hand, if the carbon balance considers both carbon dioxide sequestration and biogenic carbon dioxide emissions, the use of renewable alcohol leads to lower impact in Climate Changes. This systemic analysis also allowed for the identification of trade-offs in terms of environmental impacts when considering cultivating and processing cassava in other sites.
Pub.: 30 Dec '16, Pinned: 26 Aug '17
Abstract: A hybrid composite was prepared from cassava bagasse (CB) and sugar palm fiber (SPF) using casting technique with cassava starch (CS) as matrix and fructose as a plasticizer. Different loadings of SPF (2, 4, 6 and 8% w/w of dry starch) were added to the CS/CB composite film containing 6% CB. The addition of SPF significantly influenced the physical properties. It increased the thickness while decreasing the density, water content, water solubility and water absorption. However, no significant effect was noticed on the thermal properties of the hybrid composite film. The incorporation of SPF increased the relative crystallinity up to 47%, compared to 32% of the CS film. SEM micrographs indicated that the filler was incorporated in the matrix. The film with a higher concentration of SPF (CS-CB/SPF8) showed a more heterogeneous surface. It could be concluded that the incorporation of SPF led to changes in cassava starch film properties, potentially affecting the film performances.
Pub.: 16 Mar '17, Pinned: 26 Aug '17
Abstract: With the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) as a model drug, a series of poly(vinyl alcohol)–starch (PVA–ST) composite films for controlled drug release were prepared by a casting method. The morphology, structure, and release properties were systematically investigated. The results show that when the PVA–ST composite film containing 2,4-D (PSD) was immersed in water, the drug-release rate was high, whereas the introduction of sodium montmorillonite (Na-MMT) and an alginate ion-crosslinking structure to PSD significantly reduced the release rate and maintained the sustained release of the model drug for a longer period. A leaching experiment through the soil layer showed that the PSD drug-loaded film with Na-MMT and the alginate ion-crosslinking structure (PSDMA) possessed good release properties. The cumulative leached amount of the herbicide 2,4-D after eight irrigations was reduced to 57.6% from 100%. In addition, the PSDMA film showed favorable mechanical and thermal properties. This composite film is expected to have potential applications in the fields of agriculture, drug delivery, and more. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45051
Pub.: 16 Mar '17, Pinned: 26 Aug '17
Abstract: The molecular dynamics (MD) simulation method was used to investigate the hydrogen bonding energy of starch/glycerol system under different temperatures (range from 90 °C to 120 °C) and different glycerol contents (range from 20% to 40%, based on dry starch weight). These effects on the hydrogen bonding energy (including the total hydrogen bonding energy, hydrogen bonding energy of starch/starch, glycerol/glycerol, and starch/glycerol) were analyzed in detail. Meanwhile, glycerol plasticized starch films were prepared using casting method. The relationship between the hydrogen bonding energy and the performances of thermoplastic starch film (TPSF), such as crystallinity, mechanical properties and water uptake determined experimentally, were revealed and discussed.
Pub.: 01 Mar '17, Pinned: 26 Aug '17
Abstract: The influence of amadumbe starch nanocrystals (SNCs) at varying concentrations (2.5, 5 and 10%) on the physicochemical properties of biocomposite films prepared using two starch matrices, amadumbe and potato starches were investigated. Amadumbe SNCs exhibited square-like platelets morphology, typical of SNC derived from A-type starches. In general, the inclusion of SNCs significantly decreased water vapour permeability (WVP) of composite films whilst thermal stability and opacity were increased. Amadumbe starch films showed substantially high tensile strength (TS) compared to potato starch in the presence of SNCs. At 2.5% SNCs, TS of composite amadumbe film (8 MPa) was about four times that of composite potato films. However, SNCs ≥ 5% generally decreased TS of both potato and amadumbe films. Amadumbe SNCs can potentially be used as fillers to improve the properties of biodegradable starch films. Amadumbe starch has better film forming properties compared to potato starch.
Pub.: 16 Feb '17, Pinned: 26 Aug '17
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