Polyvinyl Alcohol Starch Research Articles

A biodegradable bi‐layer nano fibrous membrane fabricated by centrifugal spinning for active food packaging

AbstractTo solve the problem of cytotoxicity for most antimicrobial agents loaded in packaging materials, we developed a novel bi‐layer fibrous membrane by using centrifugal spinning, which of the outer layer was submicron native potato starch/polyvinyl alcohol (ST/PVA) composite fibers loaded with ZnO nanoparticles (ZnO NPs) for providing high antibacterial activity. The inner layer was nano‐based calcium alginate/polyethylene oxide (CA/PEO) fiber for providing excellent biocompatibility. The addition of ZnO caused the semicrystalline structures of ST/PVA fibers, while the CA/PEO fibers were shown semicrystalline structures due to the PEO. Fourier transform infrared indicated that posttreatment had not effect on the structures of ST/PVA/ZnO fiber, but the structure of CA/PEO fibers were affected by interaction between COO groups of alginate and Ca2+ ions. The results of mechanical property demonstrated that CA/PEO fibers showed highest stress of 3.83 ± 0.25 MPa and helpful for improving the stress of bi‐layer fibrous membrane. The obtained fibrous membrane had excellent antibacterial property with diameters of bacteriostatic zone against E. coli and S. aureus of 20.5 and 21.5 mm, respectively. On this basis, the shelf life of strawberry was improved up to 6th day by inhibit the growth of microorganisms, which indicated that the obtained fibrous membrane showed great potential for food packaging.

Synthesis of PVA–MWCNTs–UMCNOs–starch crosslinked nanocomposite biodegradable films for the removal of methylene blue and Congo red dyes from wastewater

AbstractPlastic waste and wastewater are indeed significant environmental issues that have wide‐ranging impacts on ecosystems, human health, and the economy. This study outlines the synthesis of biodegradable polyvinyl alcohol (PVA)–starch polymeric films incorporating multiwalled carbon nanotubes (MWCNTs) derived from plastic waste and unzipped carbon nanotubes oxides (UMCNOs) as co‐filled nanomaterials. These films were formulated based on data generated using a mixture design method in Design Expert 13 software, resulting in the synthesis of 19 films utilizing five types of PVA–starch polymer solutions (Types A–E). The synthesized films underwent characterization to study their surface morphology via scanning electron microscope and Fourier transform infrared spectroscopy analysis. Subsequently, the films were individually subjected to vacuum filtration, through which cationic dyes such as methylene blue (MB) and anionic dye Congo red (CR) were passed in batches. The highest removal efficiency of 96.43% for MB dye was achieved, accompanied by an exceptionally high flux of 3146.78 LMH. Similarly, the maximum removal of 88.08% for CR was observed with a flux of 1512.66 LMH. The renewable active sites mechanism resulted in increased dye removal with every cycle. Results indicated efficient reusability, particularly when washed with ethanol–water solution.

Novel intelligent packaging films based on starch/PVA with Cu-ICA nanocrystal as functional compatibilizer for monitoring food freshness

Considering public health and environmental safety, the development of reliable and efficient monitoring methods is essential to ensure food quality and safety. Herein, a new Cu-based metal organic framework (Cu-ICA) nanocrystal with ammonia-sensitive performance was built up and then introduced as a functional compatibilizer of starch/polyvinyl alcohol (STA/PVA) blend to develop high-performance intelligent packaging films for food freshness monitoring. The introduction of Cu-ICA upgraded the compatibility, mechanical strength (42.9 MPa), UV-protection (with UV transmittance of only 2.8 %), and moisture/oxygen barrier performances of STA/PVA film. Furthermore, the developed STA/PVA/Cu-ICA films presented long-term colour stability, outstanding antibacterial efficacy (over 99.5 %) toward both Escherichia coli and Staphylococcus aureus bacteria, as well as remarkable ammonia-sensitive discoloration capability. The STA/PVA/Cu-ICA films possessed visually identifiable colour change during the monitoring of shrimp spoilage. These findings indicate that the developed STA/PVA/Cu-ICA film possesses tremendous potential as an intelligent active packaging material.

Aloe vera Gel–Reinforced Biodegradable Starch–PVA Blends for Sustainable Packaging of Green Chillies

ABSTRACTThe objective of the current study was to evaluate the feasibility of Aloe vera gel as a plasticizer and crosslinker in improving the properties of starch–polyvinyl alcohol blends that could find applications in packaging. The concentration of Aloe vera gel was varied (1%, 3%, 5% and 7% wt/wt) to produce SPA‐1, SPA‐3, SPA‐5 and SPA‐7 films, respectively. The plasticizing and crosslinking characteristics associated with Aloe vera gel had a positive influence on the mechanical properties of the films. Addition of Aloe vera gel increased the tensile strength of films from 27.45 MPa (control) to 32.98, 32.53 and 32.32, for SPA‐1, SPA‐3 and SPA‐5 films, respectively. Among all the films, highest elongation at break (20.62%) was observed for SPA‐3 films. Due to crosslinking, degree of swelling, water solubility and water vapour permeability for SPA‐3 films decreased by 5.58%, 38.29% and 21.44%, respectively, compared to control films. The contact angle of the SPA‐3 film significantly increased by 49.25% when compared to control samples. Scanning electron microscope images revealed compact and smooth surface microstructure of control films, and crosslinking was evident in presence of Aloe vera gel. The rate of degradation for SPA‐3 films in soil after 40 days was enhanced by 32.25% compared to control films. SPA‐1 and SPA‐3 films were tested for use as packaging material for storage of green chillies. Chillies under unpacked conditions, in control and SPA‐1 films, turned red in 3 days. Those stored in films with 3% Aloe vera gel began to change colour later (after 5 days) with no visual evidence of microbial or fungal growth. In summary, starch–polyvinyl alcohol matrix films with 3% Aloe vera gel (SPA‐3) were effective as a sustainable alternative in increasing shelf life of foodstuff.

Biodegradable starch-polyvinyl alcohol composite films by the incorporation of lignin for packaging applications

In this work, firstly, the optimal performance ratio of potato starch and polyvinyl alcohol (PVA) was selected, and then the sustainable high-grade food packaging film was developed by adding different amounts (0, 5, 10, 15, 20, and 25 wt% based on the starch mass) of functional additive lignin into the starch - PVA film matrix. Starch - PVA based films with different amounts of lignin were studied from the aspects of morphology, physical and chemical properties, barrier properties, mechanical properties and antioxidant properties. Mechanical tests showed that lignin significantly improved the tensile strength (TS) of the film and effectively blocked the passage of water vapor. Lignin, starch and PVA were linked by hydrogen bond to form polymer network structure, which improved the interfacial compatibility between polymers. The interaction between polymer molecules and the distribution of lignin particles were confirmed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The high content of phenolic hydroxyl in lignin undergoes proton coupled electron transfer mechanism, which endows the composite film with high antioxidant activity, which is proved by DPPH radical scavenging activity experiment. At the same time, it also gives the film excellent UV barrier and antibacterial properties. The introduction of lignin in this study provides a valuable way for the preparation of multifunctional composite films using biomass as raw materials, and has a potential application prospect in food packaging.

Synthesis of a new three-dimensional cross-linked network dust suppressant and its mechanism of coal-dust inhibition

A new dust suppressant was proposed and studied by numerical calculations and experiments to control dust. The synthesis of suppressant required three steps. First, Polyvinyl alcohol starch was synthesized by the dehydration condensation of carboxymethyl starch and polyvinyl alcohol under the initiation of ammonium persulfate, requiring 288.8 kJ/mol energy. Second, polyvinyl alcohol caprolactam starch was synthesized by the dehydration condensation of caprolactam and polyvinyl alcohol starch under the initiation of ammonium persulfate, requiring 172.8 kJ/mol of energy. Third, the suppressant had the optimum wetting and bonding effects by 30 g/L polyvinyl alcohol caprolactam starch and 20 g/L sodium dodecylbenzene sulfonate. The suppressant–lignite system exhibited increased hydrogen bonds which were formed between the –OH and –COOH groups of the suppressant and the –OH, –COOH, and –NH2 groups on the coal surface. The solidified layer formed on the coal dust surface did not raise dust at wind speed of 10 m/s.

Fabrication of polyvinyl alcohol-starch controlled release active film incorporated with 2-hydroxypropyl-β-cyclodextrin/lemongrass oil emulsion for large yellow croaker (Pseudosciaena crocea) preservation

Polyvinyl alcohol-starch (PVA/ST) active films incorporated with lemongrass oil (LMO) or 2-hydroxypropyl-β-cyclodextrin, and LMO (HP-β-CD/LMO) emulsion were developed in the present work. The effects of LMO or HP-β-CD/LMO emulsion on the properties of films, and their application in large yellow croaker preservation were investigated. The average particle size and the encapsulation efficiency of the HP-β-CD/LMO emulsion were 150.07 nm and 81.32%, respectively. The scanning electron microscopy (SEM) results revealed that HP-β-CD improved the compatibility between PVA and starch, and LMO was well embedded in HP-β-CD. The incorporation of LMO or HP-β-CD/LMO enhanced the water vapour barrier property and flexibility of the film while weakening its mechanical strength. The oxygen barrier property of the film was weakened by the incorporation of LMO and strengthened by HP-β-CD/LMO. The film incorporated with HP-β-CD/LMO exhibited a little weaker antioxidant and antibacterial activities than the film containing LMO owing to their release property. The existence of HP-β-CD postponed the release of LMO from the film into food simulant (10% ethanol). The preservation results demonstrated that the film containing LMO or HP-β-CD/LMO efficiently inhibited the growth of microorganisms and lipid oxidation of fish; and delayed the decomposition of protein and freshness reduction of large yellow croaker. Additionally, the film added with HP-β-CD/LMO exhibited the best protection for fish quality. In other words, the film with the proper release property of active agents contributed to the preservation of aquatic products.

Fabrication of hydrogel controlled-released Phosphorus encapsulated in starch-polyvinyl alcohol film

Traditional soluble phosphorous(P) fertilizers can easily leach into water systems causing water eutrophication, a major environmental problem caused by an excess release of nutrients. Controlling the release of P in response to the plant demand could reduce fertilizer’s losses and also reduce environmental pollution. This study establishes a concept of controlled release fertilizer, in which a hydrogel fertilizer film is fabricated by incorporating starch, polyvinyl alcohol and ammonium dihydrogen phosphate fertilizer which tend to immobilize the release of phosphate ions and accelerate responsively their release rate in the presence of water. The experiment aims to study the effect of incorporating Starch, and Polyvinyl alcohol (PVA) to Ammonium Dihydrogen Phosphate fertilizer by varying the composition of PVA-Starch-Ammonium Dihydrogen Phosphate and preparing the films through solution casting method. FTIR is being used to investigate the effect of Starch, PVA, and Ammonium Dihydrogen Phosphate composition on the intermolecular bonding of the fabricated film. A total of 10 samples with different material composition is prepared and the intermolecular bonding between this composition is being compared with that of pure starch, pure PVA and pure Ammonium dihydrogen phosphate fertilizer. The FTIR peak will reveal evidence of hydrogen bonding between phosphate molecules and the functional group of polymer molecules as well as showed all the characteristics band of Starch, PVA and Ammonium Dihydrogen Phosphate. The varying formulation of film corresponded to varying intensity of peak and also stretching vibrations.

A slow-release fertilizer of urea prepared via biochar-coating with nano-SiO[formula omitted]-starch-polyvinyl alcohol: Formulation and release simulation

Chemical fertilizer is widely used to increase crop yield in conventional agricultural system. However, low use efficiency of chemical fertilizer could lead to its excessive application, and thus decreasing soil quality, causing environmental pollution. This study was designed to evaluate the physicochemical characteristics and slow-release properties of the biochar-coated nitrogen fertilizer with different formulations. The slow-release fertilizers were prepared with the biochar-fertilizer ratio of 1:9, 2:8 and 3:7, using urea as the fertilizer core, biochar as the coating material, and nano-SiO2-starch-polyvinyl alcohol as binder. The results showed that the compression resistance, wear resistance and moisture resistance of biochar-coated urea increased with the increase of the biochar-fertilizer ratio, which indicated that the biochar coating could decrease the ingredient loss when packaging, transportation and storage. The cumulative nitrogen release, the cumulative leaching of ammonium nitrogen and nitrate nitrogen of the biochar-coated nitrogen fertilizer were lower than those of non-coated one, especially the cumulative leaching of nitrate nitrogen decreased from 34.19% to 15.42% when the biochar coating increased from 10% to 30%. The dynamic characteristics of the cumulative release of nitrogen, the cumulative leaching of ammonium nitrogen and nitrate nitrogen with time in soil could be quantitatively simulated by Elovich equation. Therefore, biochar coating could effectively improve the use efficiency of fertilizer, and had a good slow-release performance.

Preparation of Film Based on Polyvinyl Alcohol Modified by Alkaline Starch and Lignin Fiber

This study presents an easily prepared film based on alkaline starch-polyvinyl alcohol hybrid and lignin fiber as an additive (SPL film). The SPL film was prepared under acidic conditions through a polycondensation reaction of PVA and a mixture incorporating alkaline starch and lignin fiber from agriculture or forest source. The examination using scanning electron microscopy (SEM) showed that the surface of SPL film was smooth and the lignin fiber had good compatibility within the film hybrid. Electrospray ionization mass spectroscopy (ESI-MS) and fourier transform infrared (FTIR) investigations indicated that alkaline starch and lignin fiber reacted with PVA under acidic conditions and that –CH2–O– groups were involved in the cross-linking of the SPL system. In addition, the SPL film exhibited only 4% light transmittance, which effectively reduces the ultraviolet and visible light (UV-Vis) penetration, along with good performance when exposed to thermal degradation, in which the mass loss reached around 60% at 400°C. Moreover, the SPL film acquired excellent tensile strength, which is much higher than that of PVA-lignin (PL) composite film.

Loading oregano essential oil into microporous starch to develop starch/polyvinyl alcohol slow-release film towards sustainable active packaging for sea bass (Lateolabrax japonicus)

Microporous starch (MS) was used as an adsorption carrier to load with oregano essential oil (OEO). The starch/polyvinyl alcohol (STA/PVA) films containing OEO or MS loaded with OEO (OEO-MS) were prepared. The films’ properties and their application in sea bass packaging were investigated. The FTIR spectra indicated that OEO and OEO-MS were successfully incorporated into STA/PVA film and their interaction occurred through hydrogen bonds. The SEM results demonstrated that loading OEO into MS promoted the dispersion of OEO in the film. The incorporation of OEO-MS improved tensile strength of film and reduced its flexibility. The water vapor and oxygen permeability of film decreased for OEO-MS incorporation, while the addition of OEO showed opposite results. The films containing OEO or OEO-MS both exhibited antioxidant and antibacterial activities. It showed that the release rate of OEO released from films into food simulant (10% ethanol) slowed down for loading OEO into MS. The preservation results of sea bass showed that the films containing OEO or OEO-MS could efficiently inhibit the growth of microorganisms, lipid oxidation and the decomposition of protein of sea bass. The STA/PVA film added with OEO-MS was the best to maintain the freshness of sea bass and prolonged its shelf life. Therefore, this sustained release active films showed a good potential for aquatic products packaging.

The effect of rice straw derived microfibrillated cellulose as a reinforcing agent in starch/polyvinyl alcohol/polyethylene glycol biocompatible films

At present petrochemical based plastic materials are being widely used in the packaging industries, however, due to their non-biodegradability their disposal has become a concerned issue for the environmentalists. This has shifted the concern of the researchers to manifest biodegradable, non-toxic bio plastic but either the existing biocomposite films lack antioxidant properties which makes them inefficient in food packaging or the cost of making is quite high leading to their incapability into marketing. Further, much work is not established on the extraction and characterization of cellulose from rice straw and later using it as fillers in the Starch/Polyvinyl alcohol (St/PVA) films. To target this the present study shows the potential of St/PVA films synthesized via solvent casting method, induced with cellulose fibers (CF) which are extracted from agricultural waste rice straw and polymer PEG (Polyethylene glycol) possessing antioxidant properties. The dispersion of the cellulose fillers and polymer PEG with St/PVA biocomposite films has been evaluated using Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and X- Ray Diffraction (XRD) where SEM results revealed PEG and CF promoted compatibility among St/PVA films. During physiochemical analysis it was seen that the strength and rigidity of the films improved with the addition of PEG and CF. The water vapour permeability of the composite films first increased then gradually decreased up to 25 wt% cellulose fibers. All the synthesized films with PEG showed antioxidant properties up to 20% making them capable to be used in the food industry as active packaging material.

Structural Optimization of Sorghum Straw Powder/ZnO/PVA Nanocomposite Films

This study sought to improve the utilization of sorghum straw resources and promote the industrial production of new biomass materials. Herein, we fabricated SSP/ZnO/PVA nanocomposite films from sorghum straw powder (SSP), corn starch, polyvinyl alcohol (PVA), and nanostructured ZnO via the casting method. Then, we used response surface methodology to examine the effects of the mass concentrations of SSP, glycerol (Gly), and nanostructured ZnO, as well as the starch–PVA mass ratio on the tensile strength (TS) and water vapor permeability (WVP) of the SSP/ZnO/PVA nanocomposite films. The optimum preparation conditions were as follows: SSP mass concentration of 2.0 g/150 mL, Gly mass concentration of 2.5 g/150 mL, starch–PVA mass ratio of 6:4.5, and nanostructured ZnO mass concentration of 0.7 g/150 mL. The TS and WVP of the prepared films were 47.57% higher and 27.07% lower, respectively, than those of ZnO/PVA composite films without SSP. Scanning electron microscopy and atomic force microscopy showed that the SSP/ZnO/PVA nanocomposite films had smooth surfaces and dense cross-sections, without obvious delamination or phase separation. Fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analyses revealed that SSP was highly compatible with the ZnO/PVA matrix. Thus, SSP addition could improve the crystallinity, thermal stability, and matrix interactions of SSP/ZnO/PVA nanocomposite films.

Preparation and characterization of crosslinked starch films pretreated with sodium hydroxide/amide/water solvent system

Potato starch (PS) was pretreated with a sodium hydroxide (NaOH)/amide/water solvent system, epichlorohydrin (ECH) was then added to the solution to form a crosslinked molecular network, and a crosslinked starch-polyvinyl alcohol film (SPF) was successfully fabricated after the incorporation of polyvinyl alcohol (PVA). SPF prepared from different solvent systems was characterized via scanning electron microscopy (SEM), infrared spectroscopy (IR), X-ray diffraction (XRD), thermogravimetry (TG) and differential scanning calorimetry (DSC). SPF from the NaOH/urea/formamide solvent system (SPF-UF) exhibited the most homogeneous cross-section with high crystalline intensity and thermal stability. The highest transmittance (75.16 %) and contact angle (83.5°) of SPF-UF also claimed the prominent compatibility between the crosslinked starch and PVA, partly proving the existence of the synergistic effect within the NaOH/urea/formamide solvent system, which had caused dramatic destruction of the internal hydrogen bonds of PS. In this work, the NaOH/urea/formamide solvent system as a novel system was applied to dissolve PS, to achieve the preparation of SPF with high compatibility and excellent properties, which would be more conducive for the application of this film in packaging and many other aspects.

High-performance multifunctional polyvinyl alcohol/starch based active packaging films compatibilized with bioinspired polydopamine nanoparticles

Bioinspired polydopamine (PDA) nanoparticles were synthesized and explored as functional compatibilizers in polyvinyl alcohol/starch (PVA/ST) matrix to develop high-performance multifunctional packaging film. The effect of the addition of PDA on the microstructural, mechanical, thermal, water vapor barrier, ultraviolet (UV)/high-energy blue light (HEBL) blocking, thermal insulating and antioxidant properties of PVA/ST composite films was fully investigated. Results demonstrated that the added PDA nanoparticles were evenly dispersed in the PVA/ST matrix, providing compact and dense nanocomposite films due to their compatibilization effect. Compared with virgin PVA/ST film, the resulting PVA/ST/PDA nanocomposite films exhibited greatly improved tensile strength, toughness, thermal stability, and water vapor barrier ability. Furthermore, the presence of PDA endowed PVA/ST composite film with excellent UV/HEBL blocking, thermal insulating as well as antioxidant functions. Thus, such high-performance multifunctional nanocomposite films hold the potential of protecting food quality against photothermal oxidative deterioration and extend food shelf life.

Fabrication of highly transparent and multifunctional polyvinyl alcohol/starch based nanocomposite films using zinc oxide nanoparticles as compatibilizers

This work explored biodegradable polyvinyl alcohol/starch (PVA/ST) film compatibilized by rod-like ZnO nanofillers as multifunctional food packaging materials. The influence of rod-like ZnO nanofillers on the microstructural, UV-shielding, antibacterial, mechanical, thermal, together with water barrier performances of PVA/ST composite films was fully studied. Results revealed that rod-like ZnO nanofillers could be uniformly distributed into the PVA/ST matrix, playing the role of compatibilizers to provide compact and dense nanocomposite films. The resulting nanocomposite films presented greatly improved mechanical and water vapor barrier properties as compared to virgin PVA/ST film. Moreover, the well distributed ZnO endowed PVA/ST film with excellent antimicrobial activity against both E. coli and S. aureus, together with outstanding UV-shielding capability meanwhile retaining highly optical transparency (approximately 90%). The developed PVA/ST/ZnO films were tested for packaging fresh-cut carrot slices to prevent microbial infection and prolong their shelf life. These results indicated that the developed highly transparent and multifunctional PVA/ST/ZnO nanocomposite films possess broad application prospects in active food packaging field.

Cellulose Nanofiber-Assisted Dispersion of Halloysite Nanotubes via Silane Coupling Agent-Reinforced Starch-PVA Biodegradable Composite Membrane.

HNTs (halloysite nanotubes) are widely used in reinforcing material, often used in material reinforcement and particle loading. However, their easy agglomeration causes them to have great limitations in application. In this work, two kinds of silane coupling agents (KH560 and KH570) were introduced to graft the CNF/HNT (cellulose nanofiber) nanoparticles used to reinforce the starch-polyvinyl alcohol (PVA) composite membranes. The mechanical properties, water resistance properties and thermal performance of the composite membrane were tested. The results showed that the CNF/HNTs nanoparticle system modified by two silane coupling agents enhanced the tensile strength (TS) of the starch–PVA composite membranes by increments of 60.11% and 68.35%, and, in addition, the water resistance of starch–PVA composite membrane improved. The introduction of chemical bonds formed associations and a compact network structure, which increased the thermal stability and the crystallinity of the starch–PVA composite membrane. In the study, we creatively used CNF to disperse HNTs. CNF and HNTs were combined under the action of the silane coupling agent, and then mixed into the starch–PVA membranes matrix to prepare high-performance degradable biological composite membranes.

Ag@MOF-loaded p-coumaric acid modified chitosan/chitosan nanoparticle and polyvinyl alcohol/starch bilayer films for food packing applications

Developing novel bilayer food packing film having the ability to prevent bacterial infections and capable of inhibiting oxidation is utmost important, since bacterial infections and oxidation can cause food spoilage. Ag-Metal−organic framework loaded p-coumaric acid modified chitosan (P-CS/Ag@MOF) or chitosan nanoparticles (P-CSNPs/Ag@MOF) and polyvinyl alcohol/starch (PVA/ST) were used as the upper film and lower layer film to successfully prepare a bilayer composite film. The microscopic morphology, water resistance, oil resistance, oxidation resistance, optical properties, cytotoxicity and antibacterial properties of the composite films were compared. The results showed that the surface of P-CS/Ag@MOF bilayer was relatively smooth and its tensile strength (TS) was higher (27.67 MPa). Among them, P-CS/Ag@MOF bilayer films had better oil resistance and oxidation resistance activity. In addition, the P-CS/Ag@MOF bilayer film had good UV-blocking properties and transparency. P-CSNPs/Ag@MOF bilayer film had higher antibacterial activity and cytotoxicity.

Development of Starch-Polyvinyl Alcohol Films-based pH indicator for Detection of Penicillin G Residue in Raw Milk

The detection of residual penicillin G (Pen G) in raw milk is very crucial to prevent the adverse effect from the allergy of Pen G to dairy consumer. However, the conventional detection methods require highly expensive instruments, high-skill technicians and complicated sample preparation process. In this research, a Lab-on-a-Disc (LOAD) to detect the residual Pen G in raw milk was introduced. The LOAD (ϕ: 9.0 cm) consisted of 10 micro-channels with the maximum volume of 200 μL was fabricated by laser machining of PMMA sheets. The 8.0 μm-thick polyvinyl alcohol, PVA (0.03125 % w/v) mixed with corn starch at a ratio of 3:7 (v/v) and bromocresol purple (BCP) pH indicator (0.025 % w/v) film that used as a Pen G indicator was prepared by hydrogel method and coated on the micro-channels by drop casting method. After the LOAD was rotated at 5000 rpm for 5 min at 25 °C, the BCP-(S-PVA) indicator film with the solubility of 93.56 % was dissolved in a raw milk mixed with Pen G (4.0 ng/mL) and the color of BCP-(S-PVA) film has changed from dark violet to light violet. The detection limit of BCP-(S-PVA) film to detect the Pen G in raw milk that obtained from the linear dose response curve (R2: 0.9630) is 0.17 ng/mL. Therefore, the LOAD with the BCP-(S-PVA) pH indicator is the fast and accurate promising method to determine the residual Pen G in raw milk at room temperature.

Effect of polymer blending on mechanical and barrier properties of starch-polyvinyl alcohol based biodegradable composite films

The study was aimed to improve the properties of starch-based biodegradable films by the way of polymer blending. The composite films were prepared by incorporating various proportions of PVA (10, 30, 50, 70, and 90% of starch wt.) to the starch using the solvent casting method. All films were analyzed for their mechanical behavior, barrier properties, water solubility, water contact angle, and biodegradability. Incorporation of PVA to starch polymer significantly (p < 0.05) improved the mechanical and barrier properties of composite films. The highest improvement in mechanical behavior was observed for the SP90 composite film, having a higher content of PVA. SP90 film showed 1.93 fold increase in TS, 3.74 fold increase in E and 1.72 fold increase in BS over the pure starch film. On the other hand, maximum PVA incorporation resulted in 52% and 57% decrease in WVP and OP of composite films respectively, depicting a good barrier against water vapour and oxygen gas. Fourier-transform infrared spectroscopy and scanning electron microscopy of films confirmed the excellent compatibility between starch and PVA polymer. Interestingly, the composite films degraded rapidly in moistened soil within 3 weeks of burial. Biodegradability study showed a promising potential of starch-PVA composite films for the development of eco-friendly food packaging material.