Acid Food Simulants Research Articles

Influence of Different Acids on the Transport of CdSe Quantum Dots from Polymer Nanocomposites to Food Simulants.

We fabricated polymer nanocomposites (PNCs) from low-density polyethylene and CdSe quantum dots (QDs) and used these materials to explore potential exposure after long-term storage in different acidic media that could be encountered in food contact applications. While the low-level release of QD-associated mass into all the food simulants was observed, exposure to dilute acetic acid resulted in more than double the mass transfer compared to that which occurred during exposure to dilute hydrochloric acid at the same pH. Conversely, exposure to citric acid resulted in a suppression of QD release. Permeation experiments and confocal microscopy were used to reveal mechanistic details underlying these mass-transfer phenomena. From this work, we conclude that the permeation of undissociated acid molecules into the polymer, limited by partitioning of the acids into the hydrophobic polymer, plays a larger role than pH in determining exposure to nanoparticles embedded in plastics. Although caution must be exercised when extrapolating these results to PNCs incorporating other nanofillers, these findings are significant because they undermine current thinking about the influence of pH on nanofiller release phenomena. From a regulatory standpoint, these results also support current guidance that 3% acetic acid is an acceptable acidic food simulant for PNCs fabricated from hydrophobic polymers because the other acids investigated resulted in significantly less exposure.

Extrusion and Evaluation of Chitosan Assisted AgNPs Immobilized Film Derived from Waste Polyethylene Terephthalate for Food Packaging Applications

Antimicrobial Polyethylene terephthalate (PET) film was fabricated from PET waste by the process of 2° recycling, and then characterized and demonstrated at various environment conditions to evaluate its potential for for food packaging application. Blown PET film with thickness of 0.03 mm was extruded by simultaneous in situ extrusion of vPET and rPET in the ratio of 90:10. The obtained PET90:10 film was then impregnated in 3% chitosan solution under controlled pH in order to furnish a thin layer by pre-wetting phenomenon that works as a substrate for AgNPs immobilization. The immobilization of AgNPs over PET90:10 film was asserted by FESEM and EDX. Bactericidal property of film against Escherichia coli and Staphylococcus aureus are evaluated by disk diffusion assay method. Fabricated Ag-CC-PET90:10 blown film is proposed for the purpose of food packaging. The controlled migration of Ag from packaging film to food stuff is beneficial as it prevents microbial growth in packaged food stuff. The migration kinetics of Ag from Ag-CC-PET90:10 packaging film into packaged food stuff (food simulants), in terms of Ag content and the factors influencing the migration are also studied. Two food simulants; 40% EtOH and 4% HAc are used for migration study. Migration kinetics of Ag was studied for three ST; 10, 30, and 50 °C as well as for four St; 1, 24, 72 and 168 h. Results indicate that the maximum migrations of Ag in the alkaline and acidic food simulants are found to be 0.01812 and 0.07272 ppm respectively, at maximum ST and St. Migration of Ag content was found to be higher in acidic food simulant as compare to alkaline food simulant due to oxidative dissolution. The maximum Ag migrated content (50 °C, 168 h) was found under the permissible range prescribed by USFDA. The application of Ag-CC-PET90:10 blown film as food packaging material is itself an innovative and ecofriendly approach as post-consumption discarded PET waste can brought be up in utilization by means of 2° recycling.

Impact of migration test method on the release of silver from nanosilver-polyethylene composite films into an acidic food simulant

Abstract Impact of migration test method on the release of nanocomponent from nano-polymer composite films intend for food contact is seldom addressed. In this study, release of silver from nanosilver-polyethylene composite films into 3% acetic acid under different migration test methods were investigated, with the aim to understand the effect of exposure condition on silver release. The following test protocols were designed for the experiment: single-sided contact versus two-sided contact, more versus fewer cut edges, and glass migration cell versus metal one. The results show that samples under two-sided contact had higher silver release than that under one-sided contact. Besides, increasing the number of cut edges largely increased the release of silver, while using metal instead of glass migration cell significantly reduced the release. Furthermore, partially floated films have lower silver release than that of totally immersed films. As a conclusion, impact of migration test method on the release of nanocomponent is different from that on the migration of common migrants and therefore, exposure condition should be carefully taken into account in the design of migration test for nanosilver-polyethylene composite films to minimize any potential negative impact on obtaining comparable results.

Influence of polymer swelling and dissolution into food simulants on the release of graphene nanoplates and carbon nanotubes from poly(lactic) acid and polypropylene composite films

ABSTRACTThe study compared the effects of swelling and dissolution of a matrix polymer by food simulants on the release of graphene nanoplates (GNPs) and multiwall carbon nanotubes (MWCNTs) from poly(lactic) acid (PLA) and polypropylene (PP) composite films. The total migration was determined gravimetrically in the ethanol and acetic acid food simulants at different time and temperature conditions, while migrants were detected by laser diffraction analysis and transmission electron microscopy. Swelling, thermal analysis, and scanning electron microscopy were applied to characterize the degradation of polymer films at the migration conditions. The release of nanoparticles was found in a high‐temperature migration test of 4 h at 90 °C. The hydrolytic dissolution of the PLA polymer in the food simulants caused a migration of GNPs (>100 nm) from the PLA/GNP/MWCNT films into the simulant solvents, while the entangled MWCNTs formed a network on the film surface, preventing their migration from the PLA composite films. In contrast, the PP polymer slightly swells in ethanol solvents, allowing some short carbon nanotubes to be released from the surface and cut edges of the PP/MWCNT film into food simulants. Mathematical modeling of diffusion was applied that accounts for type of polymer, time–temperature conditions, and solvent concentration; model parameters were validated with experimental results. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45469.

Release of carbon nanoparticles of different size and shape from nanocomposite poly(lactic) acid film into food simulants

ABSTRACTPoly(lactic) acid (PLA) film with 2 wt% mixed carbon nanofillers of graphene nanoplates (GNPs) and multiwall carbon nanotubes (MWCNTs) in a weight ratio of 1:1 with impurities of fullerene and carbon black (CB) was produced by layer-to-layer deposition and hot pressing. The release of carbon nanoparticles from the film was studied at varying time–temperature conditions and simulants. Migrants in simulant solvents were examined with laser diffraction analysis and transmission electron microscopy (TEM). Film integrity and the presence of migrants on the film surfaces were visualised by scanning electron microscopy (SEM). The partial dissolution of PLA polymer in the solvents was confirmed by swelling tests and differential scanning calorimetry (DSC). Nanoparticle migrants were not detected in the simulants (at the LOD 0.020 μm of the laser diffraction analysis) after migration testing at 40°C for 10 days. However, high-temperature migration testing at 90°C for 4 h provoked a release of GNPs from the film into ethanol, acetic acid and oil-based food simulants. Short carbon nanotubes were observed rarely to release in the most aggressive acetic acid solvent. Obviously, the enhanced molecular mobility at temperatures above the glass transition and partial dissolution of PLA polymer by the food simulant facilitate the diffusion processes. Moreover, shape, size and concentration of nanoparticles play a significant role. Flexible naked GNPs (lateral size 100–1000 nm) easily migrate when the polymer molecules exhibit enhanced mobility, while fibrous MWCNTs (> 1 μm length) formed entangled networks on the film surfaces as the PLA polymer is partly dissolved, preventing their release into food simulants. The impurities of fullerenes and CB (5–30 nm) were of minor concentration in the polymer, therefore their migration is low or undetectable. The total amount of released migrants is below overall migration limits.

Effect of organic additives on silver release from nanosilver-polyethylene composite films to acidic food simulant.

The effects of organic additives (Irgafos 168, Irganox 1076, Tinuvin 622, Chimassorb 944, UV-P, and UV-531) on silver release from nanosilver-polyethylene composite films into an acidic food simulant (3% acetic acid) were investigated using inductively coupled plasma mass spectrometry. The limits of detection and quantification, coefficient of determination, and recoveries of the method used were 3.7ngL-1, 12.4ngL-1, 0.999, and 89-113%, respectively. The results indicated that additives can affect silver release via two simultaneous processes: (i) reactions between organic additives and silver that promote silver release from the composite film to the acidic food simulant; and (ii) the promotion or inhibition of silver release by affecting silver oxidation. High temperature and humidity treatment of the composite films was found to significantly increase silver release by promoting silver oxidation.

Human exposure assessment of silver and copper migrating from an antimicrobial nanocoated packaging material into an acidic food simulant

To examine the human exposure to a novel silver and copper nanoparticle (AgNP and CuNP)/polystyrene-polyethylene oxide block copolymer (PS-b-PEO) food packaging coating, the migration of Ag and Cu into 3% acetic acid (3% HAc) food simulant was assessed at 60 °C for 10 days. Significantly lower migration was observed for Ag (0.46 mg/kg food) compared to Cu (0.82 mg/kg food) measured by inductively coupled plasma – atomic emission spectrometry (ICP-AES). In addition, no distinct population of AgNPs or CuNPs were observed in 3% HAc by nanoparticle tracking analysis (NTA) and transmission electron microscopy (TEM). The predicted human exposure to Ag and Cu was used to calculate a margin of exposure (MOE) for ionic species of Ag and Cu, which indicated the safe use of the food packaging in a hypothetical scenario (e.g. as fruit juice packaging). While migration exceeded regulatory limits, the calculated MOE suggests current migration limits may be conservative for specific nano-packaging applications.

Migration Kinetics of Ethylene Glycol Monomer from Pet Bottles into Acidic Food Simulant: Effects of Nanoparticle Presence and Matrix Morphology

AbstractIn this study, migration of ethylene glycol from polyethylene terephthalate (PET) bottles (neat PET and PET nanocomposites) into acidic food simulant is investigated. Nanocomposite pellets were prepared by melt blending of PET and TiO2 nanoparticles. The stretch blow molding machine was used to make the preforms and bottles from neat PET and nanocomposites. DSC analyses showed that the presence of nanoparticles at 3 wt % noticeably affected the crystallization temperature, Tc, and the final degree of crystallinity of PET. The incorporation of nanoparticles in the PET matrix leads to a substantial decrease of water vapor permeability. Nanoparticles also decreased the diffusivity of migrants due to the higher degree of crystallinity. The acetic acid samples were stored at 45C for 15 days. Gas chromatography analysis demonstrated that the migration of ethylene glycol from nanocomposite bottles was less than the neat PET. The polymer‐specific parameters (AP values) from mathematical migration models were derived from the experimental data. The diffusion coefficients (DP) based on Piringer's model showed a considerable difference between DP of nanocomposites and neat PET. It was concluded that the migration of monomers from food contact materials considerably depends on the structure of the manufactured packaging plastic.Practical ApplicationsPolyethylene terephthalate (PET) nanocomposite pellets containing 3% wt TiO2 nanoparticles were prepared by melt blending and PET bottles were made by injection stretch blow molding. The results showed that incorporation of TiO2 nano‐fillers in PET matrix considerably increased crystallinity and rigidity of PET packaging material and decreased the amorphous region in the polymer matrix. TiO2 nanoparticles with uniform distribution in the polymer matrix created a tortuous path, leading to reduce in monomer migration from packaging material into food simulant. Mathematical model used in this study was a practical tool for better understanding of migration process. Improved barrier properties and lower monomer migration from PET bottles into food could increase the application of PET nanocomposites in food packaging.

Silver nanoparticle release from commercially available plastic food containers into food simulants

Silver nanoparticles (AgNPs) are currently being used in many different kinds of consumer products in order to take advantage of their antimicrobial properties. However, the potential migration of silver nanoparticles into food and subsequent consumer exposure has hardly been addressed. In the current study, we investigated four brands of commercially available plastic food storage containers and measured the total amount of silver, particle size and number concentration, and the migration rates into three different food simulants (Milli-Q grade water, 10 % ethanol, and 3 % acetic acid) for 10 days at 40 °C. The experimental setup was made according to the European Commission Directive (EU 10/2011) for articles intended to be in contact with food. The total amount of silver in plastic containers and migration solutions was quantified by ICP-MS analysis, and the size of the migrated particles was investigated by single particle ICP-MS and TEM-EDS. The total mass and median size of released particulate Ag were generally highest in 3 % acetic acid for three out of four food container brands. The total content of silver in the containers varied from 13 to 42 µg/g. The highest migration was observed in the 3 % acetic acid food simulant for all four brands of containers, with total silver release up to 3.1 ng/cm2 after 10 days. In conclusion, the experimental results show that silver has the potential of migrating into food, especially when in contact with more acidic substances.

Migration Model of Toxic Metals from Ceramic Food Contact Materials into Acid Food

Migration studies of lead and cadmium from ceramic food contact materials into acid food simulants were conducted under various time–temperature conditions to investigate the kinetics of the leaching of lead and cadmium. A mathematical model based on one‐dimensional Fickian diffusion theory was derived in order to describe the migration behaviour of lead and cadmium. Moreover, diffusion coefficients of toxic metals were obtained by fitting the short‐time (24 h) migration data to the model. Comparisons of model solutions with experimental data obtained from the medium‐time tests (up to 600 h) and long‐time tests (up to 130 days) were carried out to verify the proposed model and the values of diffusion coefficients obtained from the short‐time test. Results show that the model fits the experimental data obtained under 20 and 40°C well but fails to fit the experimental data at 60°C. This indicates a change of the migration mechanisms from ion exchange to glass network dissolution as a result of higher temperature. Furthermore, results of migration experiments also reveal that the effects of temperature on the diffusion of lead and cadmium follow the Arrhenius law and that the leaching amounts of lead and cadmium decrease with pH value of the food simulant. Copyright © 2015 John Wiley & Sons, Ltd.

Antimicrobial packaging based on linear low-density polyethylene compounded with potassium sorbate

In recent years much attention has been devoted to active packaging technologies that offer new opportunities for the food industry and food preservation. In the present study, antimicrobial films were developed by compounding of a neat linear low density polyethylene (LLDPE) or its blend with ethylene vinyl acetate (EVA), with potassium sorbate (KS). A new approach for preservative incorporation into a polyolefin matrix was used to obtain uniform dispersions of the preservative in the films. This approach includes using glycerol monooleate (GMO) as a dispersant and preparation of GMO/KS concentrate by strong mechanical mixing. The antimicrobial activity of the films was studied using the yeast strain Saccharomyces cerevisiae S288C. All compositions of LLDPE or LLDPE/EVA containing GMO and KS demonstrated antimicrobial activity. Release tests showed that KS migrates from compression molded 300 μm films to an acidic food simulant and its diffusion is controlled by the Fickian diffusion rule. Thermal stability, rheological behavior, morphology and KS dispersion in the polymer matrices of the prepared blends and films were investigated. The results indicate that the presence of KS in the polymer matrix significantly improves the thermal stability of the blends compared with the neat matrices without a significant viscosity reduction.

Migration of Toxic Metals from Ceramic Food Packaging Materials into Acid Food Simulants

Long-term extraction experiments were carried out on glazed tile specimens with 4 and 10% (v/v) acetic acid, 1% (w/v) citric acid, and 1% (v/v) lactic acid solution in three temperature conditions (20, 40, and 60°C) to investigate the effect of temperature and pH value on extraction of lead, cobalt, nickel, and zinc from ceramic food packaging materials and to study the extraction kinetics of toxic metals. Results showed that except at 60°C the amount of extraction of lead, cobalt, nickel, and zinc had linear dependence on time at longer times and removal of these toxic metals under other conditions increased linearly with the square root of the time, indicating a diffusion-controlled process. The amount of these toxic metals leached out from ceramic food packaging materials into the leachate, and the leaching rate increased with temperature and decreased with pH value of the food simulants. In addition, among these four toxic metals lead was the least leachable element, and nickel was the most leachable one. Disagreement between the ratios of the oxide of lead, cobalt, nickel, and zinc in the glaze and their release in the leachate suggested that extraction of these toxic metals was an incongruent dissolution process.

The effect of an acidic food-simulating environment on the shear bond strength of self-ligating brackets with different base designs.

Aim. This study aims to evaluate the effect of acidic food simulant and (acetic acid 3%) on the shear bond strength (SBS) and adhesive remnant index (ARI) scores of one conventional and three different self-ligating brackets with different base designs. Materials and Methods. Freshly extracted first maxillary premolars (n = 160) were embedded in resin blocks. A conventional stainless steel bracket, Equilibrium 2, and three types of self-ligating brackets, Speed, In-Ovation R, and Damon 3MX, were bonded to teeth and exposed to distilled water (groups 1, 3, 5, and 7) or acetic acid 3% (groups 2, 4, 6, 8) for 12 weeks. SBS and ARI were calculated and statistical analysis was performed with the analysis of variance (SBS) or χ 2 test (ARI) to compare values between the different groups. Results. Equilibrium 2 and In-Ovation R showed a significantly lower SBS in the acidic environment than in distilled water. Significant differences in ARI scores were found for Equilibrium 2 after immersion in an acidic environment, shifting from 0 in distilled water to 2 in an acidic environment. Conclusions. Equilibrium 2 and In-Ovation R brackets showed a significant decrease in SBS after a 12-week immersion in acetic acid 3%, although all groups showed clinically acceptable SBS. Equilibrium 2 showed significant differences in ARI scores when exposed to acetic acid 3%.

Migration of silver from commercial plastic food containers and implications for consumer exposure assessment

Food storage containers with embedded silver as an antibacterial agent promise longer durability of food. For risk assessment the release of this silver into the stored food and resulting human exposure need to be known. For the purpose of exposure assessment, silver migration from commercial plastic containers with declared content of ‘nano-’ or ‘micro-silver’ into different food simulants (water, 10% ethanol, 3% acetic acid, olive oil) was quantitatively determined by ICP-MS and the form of the released silver was investigated. The highest migration of silver was observed for the acidic food simulant with 30 ng silver cm−2 contact surface within 10 days at 20°C. In a second and third use cycle, migration dropped by a factor of up to 10, so that the maximum cumulated release over three use cycles was 34 ng cm−2. The silver release over time was described using a power function and a numerical model that simulates Fickian diffusion through the plastic material. The released silver was found to be in ionic form, but also in the form of silver nanoparticles (around 12%). Consumer exposure to the total amount of silver released from the food containers is low in comparison with the background silver exposure of the general population, but since natural background concentrations are only known for ionic silver, the exposure to silver nanoparticles is not directly comparable with a safe background level.

Migration of Aluminum and Silicon from PET/Clay Nanocomposite Bottles into Acidic Food Simulant

Poly(ethylene terephthalate) (PET)/clay nanocomposite samples were prepared by melt blending PET and Cloisite 20A nanoparticles. A stretch blow‐moulding machine was used to produce bottles from neat PET and PET nanocomposite. Tests were performed on the migration of aluminum and silicon from PET nanocomposite bottles into acidic food simulant. The samples were stored at room temperature (about 25°C) and 45°C for time durations ranging from 7 to 90 days. A specific surface of sheets (prepared from PET/clay nanocomposite) immersed in acidic food simulant, and two‐sided migration of Al and Si was investigated. According to X‐ray diffraction analysis, the nanoclays show intercalated structure in the PET matrix. Transmission electron microscopy and atomic force microscopy micrographs displayed both intercalation and exfoliation morphology for PET/clay nanocomposites. Inductively coupled plasma was used to quantify amounts of Al and Si that had migrated into the acidic food simulant. It was observed that the migration process is dependent on storage time and temperature, and the molar ratio of aluminum and silicon in the acidic aqueous solution (Al/Si)aq to the ratio in the solid phase of prepared nanocomposites (Al/Si)solid was about 23% higher in the samples stored at 45°C. Copyright © 2013 John Wiley & Sons, Ltd.

Migration of Silicon from Nanocomposite Packaging Materials into Acidic Food Simulant

PET/Clay nanocomposites were prepared by the melt blending of PET and 3% wt. closite20A nanoparticles. The stretch blow molding machine was used to produce bottles from neat PET and PET nanocomposite. Migration of silicon from PET nanocomposite bottles into acidic food simulnat was studied at two storage temperatures (25°C and 45°C) in different time intervals from 7 to 70 days. A specific surface of sheets (prepared from PET/clay nanocomposite) immersed in acidic food simulnat and two-sided migration of silicon investigated. Using XRD analysis and TEM micrographs displayed both intercalation and exfoliation morphology for PET/clay nanocomposites. Inductive coupled plasma (ICP) used to quantify the amount of Silicon migrated into acidic food simulnat. It was observed that the migration process is depended on the storage time and temperature as well as the morphology of nanocomposites.

Migration of Lead, Cobalt, Nickel and Zinc from Ceramic Glazes by Acid Food Simulants

Migration of Lead, Cobalt, Nickel and Zinc from Ceramic Glazes by Acid Food Simulants

Effect of Food Characteristics, Storage Conditions, and Electron Beam Irradiation on Active Agent Release from Polyamide‐Coated LDPE Films

We investigated the effect of electron beam irradiation, storage conditions, and model food pH on the release characteristics of trans-cinnamaldehyde incorporated into polyamide-coated low-density polyethylene (LDPE) films. Active agent release rate on irradiated films (up to 20.0 kGy) decreased by 69% compared with the nonirradiated controls, from 0.252 to 0.086 microg/mL/h. Storage temperature (4, 21, and 35 degrees C) and pH (4, 7, and 10) of the food simulant solutions (10% aqueous ethanol) affected the release rate of trans-cinnamaldehyde. As expected, antimicrobial release rate decreased to 0.013 microg/mL/h at the refrigerated temperature (4 degrees C) compared to the higher temperatures (0.029 and 0.035 microg/mL/h at 21 and 35 degrees C). The fastest release rate occurred when exposed to the acidic food simulant solution (pH 4). In aqueous solution, trans-cinnamaldehyde was highly unstable to ionizing radiation, with loss in concentration from 24.50 to 1.36 microg/mL after exposure to 2.0 kGy. Fourier transform infrared (FTIR) analysis revealed that exposure to ionizing radiation up to 10.0 kGy did not affect the structural conformation of LDPE/polyamide films and the trans-cinnamaldehyde in the films, though it induced changes in the functional group of trans-cinnamaldehyde when dose increased up to 20.0 kGy. Studies with a radiation-stable compound (naphthalene) showed that ionizing radiation induced the crosslinking in polymer networks of LDPE/polyamide film and caused slow and gradual release of the compound. This study demonstrated that irradiation serves as a controlling factor for release of active compounds, with potential applications in the development of antimicrobial packaging systems.

Specific determination of 20 primary aromatic amines in aqueous food simulants by liquid chromatography–electrospray ionization-tandem mass spectrometry

A multi-analyte method without any pre-treatment steps using reversed-phase liquid chromatography–electrospray ionization-tandem mass spectrometry (LC–ESI-MS/MS) was developed and applied for the determination of 20 primary aromatic amines (PAA) associated with polyurethane (PUR) products or azo-colours. The method was validated in-house for water and 3% acetic acid food simulants using spiked migrates from plastic laminates. Detection limits ranged from 0.27 to 3 μg amine/L food simulants, and RSD values of within-laboratory reproducibility at the 2 μg PAA/L level ranged from 3.9 to 19%. PAA migration from plastic laminates and black nylon cooking utensils were determined with the method, and high levels of 4,4′-methylenedianiline and aniline were found in migrates from about half of the tested cooking utensils. The method fulfils present legislative demands in the EU for screening and verification of PAA migration from food contact materials.

Migration of bisphenol A (BPA) from epoxy can coatings to jalapeño peppers and an acid food simulant.

Effects of heat processing, storage time, and temperature on migration of bisphenol A (BPA) from an epoxy type can coating to an acid food simulant and jalapeño peppers were determined. Commercial jalapeño pepper cans (8 oz, dimensions 211 x 300) were stored at 25 degrees C for 40, 70, and 160 days. A solution of 3% acetic acid was canned in 211 x 300 cans from the same batch used for jalapeño peppers. Heat processing was applied to two-thirds of the cans, and the remaining cans were not heat processed. Cans were stored at 25 and 35 degrees C for 0, 40, 70, and 160 days. Results showed that there is a minimal effect of heat treatment. An effect of storage time on migration of BPA during the first 40 days at 25 degrees C was observed. An increase on migration of BPA was observed with storage time at 35 degrees C. The highest level of migration was 15.33 microg/kg of BPA at 160 days at 35 degrees C. A correction factor of approximately 0.4 was calculated for migration under simulating conditions of storage compared to the real ones. The highest level of BPA found in jalapeño peppers cans, surveyed from three supermarkets, was 5.59 +/- 2.43 microg/kg. Migration of BPA, performed according to the European and Mercosur conditions, was 65.45 +/- 5.29 microg/kg. All the migration values found in this study were below those legislation limits (3 mg/kg).