Effects of area,year and climatic factors on Barbera wine characteristics studied by the combination of 1H-NMR metabolomics and chemometrics

Barbera is one of the most common red grape in Italy, found in almost every region of the country. The widespread market of the corresponding wine deserves studies on its traceability and authenticity. To this end, the ¹H-NMR database of several wine metabolites was built using spectra recorded in a wine-like matrix containing ethanol and tartaric acid with pH precisely adjusted. The combination of ¹H-NMR metabolomics study and chemometrics (multivariate data analysis) is able to discriminate between samples of such a wine produced in three different areas of Piedmont. The influence of climatic factors on the wine characteristics has also been studied.     

Evaluation of the effect of carvacrol on the Escherichia coli 555 metabolome by using H-NMR spectroscopy

Cultures of Escherichia coli 555 were grown at four levels of carvacrol (0–2 mM) and the E. coli endo-metabolome was extracted and measured by ¹H NMR spectroscopy. The results show that glucose concentration is going up with concentration of carvacrol and so do formate until the highest concentration is reached, from which point it suddenly decreases. This is interpreted as if the bacteria are increasingly unable to further metabolize glucose and as if the bacteria increasingly shifts with higher levels of carvacrol toward sugar fermentation as carbon source, until the level of carvacrol reaches a level (2.00 mM), where the E. coli must give up. Additionally, the multivariate Principal Component Analysis suggests that the adaptation occurring at sub-lethal doses of carvacrol is different from that occurring at higher doses.     

Assessment of the migration potential of nanosilver from nanoparticle-coated low-density polyethylene food packaging into food simulants

An experimental nanosilver-coated low-density polyethylene (LDPE) food packaging was incubated with food simulants using a conventional oven and tested for migration according to European Commission Regulation No. 10/2011. The commercial LDPE films were coated using a layer-by-layer (LbL) technique and three levels of silver (Ag) precursor concentration (0.5%, 2% and 5% silver nitrate (AgNO₃), respectively) were used to attach antimicrobial Ag. The experimental migration study conditions (time, temperature and food simulant) under conventional oven heating (10 days at 60°C, 2 h at 70°C, 2 h at 60°C or 10 days at 70°C) were chosen to simulate the worst-case storage period of over 6 months. In addition, migration was quantified under microwave heating. The total Ag migrant levels in the food simulants were quantified by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Mean migration levels obtained by ICP-AES for oven heating were in the range 0.01–1.75 mg l^?1. Migration observed for microwave heating was found to be significantly higher when compared with oven heating for similar temperatures (100°C) and identical exposure times (2 min). In each of the packaging materials and food simulants tested, the presence of nanoparticles (NPs) was confirmed by scanning electron microscopy (SEM). On inspection of the migration observed under conventional oven heating, an important finding was the significant reduction in migration resulting from the increased Ag precursor concentration used to attach Ag on the LDPE LbL-coated films. This observation merits further investigation into the LbL coating process used, as it suggests potential for process modifications to reduce migration. In turn, any reduction in NP migration below regulatory limits could greatly support the antimicrobial silver nanoparticle (AgNP)-LDPE LbL-coated films being used as a food packaging material.     

Symbolic Metabolite Analysis of Pickled Wax Gourd in Eastern China by 1H-NMR Spectroscopy and Multivariate Data

Pickled wax gourd is a traditional fermented vegetable product popular in Zhejiang province, eastern China; however, information on their quality is quite limited. In the present study, we investigated the quality of pickled wax gourd at different processing phases using nuclear magnetic resonance, principal component analysis, and orthogonal partial least squares-discriminant analysis. According to the spectra of ¹H NMR, 36 kinds of metabolites were found at the 20th day of fermentation. Principal component analysis score plot showed that diverse marker metabolites occurred in all designated sampling points (every other 5 days), apart from the samples between the 10th day and 15th day of fermentation. Symbolic metabolites at the first 5 days were L-rhamnose, lactate, fatty acid, arginine, N-acetylglutamate, succinate, phosphorylcholine, glutamate, ornithine, lysine, and β-glucose. Lactate, succinate, glycine, proline, and choline were detected at the following period from the 5th to the 10th day of fermentation. Lactate, succinate, glycine, mannitol, choline, and α-ketoglutaric acid were the main metabolites on the 15th and 20th day. The diversity of metabolites fits with the microbial species structure in different pickling periods. This method was proved to be effective for monitoring the pickling process in real time.     

Perfluorinated compounds in food simulants after migration from fluorocarbon resin-coated frying pans,baking utensils,and non-stick baking papers on the Korean market

ABSTRACT

Perfluorinated compounds (PFCs) are used in manufacturing food contact materials, including non-stick cookware coatings and oil- and moisture-resistant paper coatings. The chemical stability of PFCs poses an issue for human safety, as they do not degrade well naturally and hence may accumulate in the body. In terms of food safety, since dietary intake is thought to be a major source of exposure to PFCs, it is necessary to assess the migration of PFCs from food packaging articles to food under typical cooking and storage conditions. An analytical method was developed for assessing the migration of 16 PFCs from food contact materials to food simulants using liquid chromatography–tandem mass spectrometry. The applicability of the method for regular inspection was assessed by monitoring 312 samples. Based on the results of the exposure assessment, all food contact materials deemed to be safe for use, which evaluated migrated concentrations and dietary food intake.     

Effect of antioxidants and light stabilisers on silver migration from nanosilver-polyethylene composite packaging films into food simulants

The effect of exposure time, temperature and food simulants, especially additives, on the release of silver from nanosilver-polyethylene composite films to food simulants was studied. Two different type of nanosilver-polyethylene composite films (with or without additives) were chosen to conduct the experiment with the aim of exploring the behaviour of silver migration. It was shown that the migration of silver into 50% ethanol at 40 and 70°C was much less than that into 3% acetic acid. With the increase of exposure time and temperature, the release of silver increased. The migration even continued after a long exposure time (14 days at 20°C, 10 days at 40°C, and 6 days at 70°C respectively). Only about 0.15‰ of silver migrated from composite films with the additives into 3% acetic acid after 6 days of exposure at 70°C, while about 1.3% of silver migrated from composite films that did not contain additives under the same conditions. This could be because the addition of the antioxidants and light stabilisers prevents silver from being oxidised, which is an important way for the release of silver.     

Study of silver ion migration from melt-blended and layered-deposited silver polyethylene nanocomposite into food simulants and apple juice

Colloidal silver nanoparticles were prepared via chemical reduction using polyethylene glycol (PEG) as a reducing agent, stabiliser and solvent. Silver polyethylene nanocomposites were produced via two methods, namely: melt blending and layer-by-layer (LBL) deposition of silver nanoparticles onto a polyethylene film. The silver ion release from either melt-blended or LBL-deposited nanocomposites into a food simulant and apple juice during 30 days at 4°C and 40°C was determined by atomic absorption spectroscopy. The effects of incorporating or coating of silver nanoparticles, silver concentration, contact media, temperature and time on silver ion migration were evaluated using factorial design. The diffusion coefficients of silver ions into the food simulants and apple juice were calculated using the Miltz model. The results indicated that the production method of nanocomposite, silver concentration, temperature, time and contact media showed a significant effect (p < 0.05) on silver ion migration. The quantity of silver ion migration from the nanocomposites into the food simulants and apple juice was less than the cytotoxicity-level concentration (10 mg kg^?1) in all cases over 30 days. The coating of silver nanoparticles, higher silver concentration in the nanocomposite, higher temperature and acidic property of contact liquid all promoted the silver ion release from the nanocomposite films. The migration of silver ions from nanocomposites obeyed first-order diffusion kinetics.     

Characterizing the migration of antioxidants from polypropylene into fatty food simulants

The migration (diffusion and equilibrium) processes of antioxidants (AOs) from polypropylene (PP) films of different thicknesses into n-heptane and 95% ethanol as fatty food simulants were analysed at 20, 37 and 60°C. Heptane fully extracted the AOs from the polymer while a partition equilibrium described the migration to ethanol. The kinetics of migration were also studied via the diffusion coefficients. As expected, diffusion was found to be faster when the polymer was in contact with heptane, due to polymer swelling by the solvent. The kinetics of the process in ethanol was described by different theoretical expressions which are discussed. Equations disregarding partition equilibrium failed to describe the process and the diffusion coefficient values obtained through them were much smaller than the actual ones and dependent on film thickness. The results also showed the significance of food simulant selection in the analysis of food-packaging interactions and migration variability with thickness.     

Mineral oil migration from paper-based packaging into food,investigated by means of food simulants and model substances

ABSTRACT

Mineral oil hydrocarbons (MOH) are known to be mixtures of non-identified substances, which can migrate from, inter alia, recycled food packaging into food products. Such substances may have carcinogenic potential, which leads to a need to avoid their migration into food. In this article, we investigate the possible use of food simulants and model substances to simplify migration approaches. Tenax and Sorb-Star were chosen as simulant media. To stage the action of known components as a replacement for the migration of MOH, 16 single substances, including n-alkanes and aromatic compounds, were used. Kinetic studies were carried out at a maximum of 60°C with contact times of up to 14 days in touching contact with a medium or in gas-phase transfer to it. The results demonstrated that migration was predominantly a function of temperature, time and contact type, but it was also dependant on the molecular weight and polarity of the substances. Due to their low polarity, alkanes showed higher migration to the lipophilic food simulants than did pure aromatics without alkylation. Additionally, alkylated aromatics represent mineral oil aromatic hydrocarbons (MOAH) more realistically. In contrast to Tenax in the gas-phase transition, Tenax in touching contact may lead to overestimated values at higher temperatures. Migration values for Sorb-Star are in similar regions for both contact types. However, the values of the touching contact experiments were slightly higher than those of the gas-phase transfer. The results for Sorb-Star and Tenax with transport solely over the gas phase are also in good agreement. Sorb-Star generally represents an optimal simulant for chunky foods, whereas Tenax seems a good simulant for food types with a high contact surface. Temperatures up to 40°C are appropriate for most types of migration experiments, whereas 60°C should only be used as an option for experiments with Sorb-Star.     

Determination of siloxanes in silicone products and potential migration to milk,formula and liquid simulants

A pressurised solvent extraction procedure coupled with a gas chromatography–mass spectrometry–selective ion monitoring (GC–MS–SIM) method was developed to determine three cyclic siloxanes, octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), dodecamethylcyclohexasiloxane (D6) and three linear siloxanes, octamethyltrisiloxane (L3), decamethyltetrasiloxane (L4), dodecamethylpentasiloxane (L5), in silicone products. Additionally, two different extraction methods were developed to measure these siloxanes migrating into milk, infant formula and liquid simulants (50 and 95% ethanol in water). The limits of quantification (LOQs) of the six siloxanes ranged from 6?ng/g (L3) to 15?ng/g (D6). Silicone nipples and silicone bakewares were extracted using pressurised solvent extraction (PSE) and analysed using the GC–MS–SIM method. No linear siloxanes were detected in the silicone nipple samples analysed. The three cyclic siloxanes (D4, D5 and D6) were detected in all silicone nipple samples with concentrations ranging from 0.5 to 269?µg/g. In the bakeware samples, except for L3, the other five siloxanes were detected with concentrations ranging from 0.2?µg/g (L4) to 7030?µg/g (D6). To investigate the potential migration of the six siloxanes from silicone nipples to milk and infant formula, a liquid extraction and dispersive clean-up procedure was developed for the two matrices. The procedure used a mix of hexane and ethyl acetate (1?:?1, v/v) as extraction solvent and C₁₈ powder as the dispersive clean-up sorbent. For the liquid simulants, extraction of the siloxanes was achieved using hexane without any salting out or clean-up procedures. The recoveries of the six siloxanes from the milk, infant formula and simulants fortified at 50, 100, 200, 500 and 1000?µg/l ranged from 70 to 120% with a relative standard derivation (RSD) of less than 15% (n?=?4). Migration tests were performed by exposing milk, infant formula and the liquid simulants to silicone baking sheets with known concentrations of the six siloxanes at 40°C. No siloxanes were detected in milk or infant formula after 6?h of direct contact with the silicone baking sheet plaques, indicating insignificant migration of the siloxanes to milk or infant formula. Migration tests in the two simulants lasted up to 72?h and the three cyclic siloxanes were detected in 50% ethanol after an 8-h exposure and after 2?h in 95% ethanol. The highest detected concentrations of D4, D5 and D6 were 42, 36 and 155?ng/ml, respectively, indicating very limited migration of D4, D5 or D6 into the two simulants.     

Characterisation and potential migration of silver nanoparticles from commercially available polymeric food contact materials

The potential for consumer exposure to nano-components in food contact materials (FCMs) is dependent on the migration of nanomaterials into food. Therefore, characterising the physico-chemical properties and potential for migration of constituents is an important step in assessing the safety of FCMs. A number of commercially available food storage products, purchased domestically within the United States and internationally, that claim to contain nanosilver were evaluated. The products were made of polyethylene, polypropylene and polyphenylene ether sulfone and all contained silver (0.001–36 mg kg^–1 of polymer). Silver migration was measured under various conditions, including using 3% acetic acid and water as food simulants. Low concentrations (sub-ppb levels) of silver were detected in the migration studies generally following a trend characterised by a surface desorption phenomenon, where the majority of the silver migration occurred in the first of three consecutive exposures. Silver nanoparticles were not detected in food simulants, suggesting that the silver migration may be due solely to ionic silver released into solution from oxidation of the silver nanoparticle surface. The absence of detectable silver nanoparticles was consistent with expectations from a physico-chemical view point. For the products tested, current USFDA guidance for evaluating migration from FCMs was applicable.     

Migration of fluorochemical paper additives from food-contact paper into foods and food simulants

Fluorochemical-treated paper was tested to determine the amount of migration that occurs into foods and food-simulating liquids and the characteristics of the migration. Migration characteristics of fluorochemicals from paper were examined in Miglyol, butter, water, vinegar, water-ethanol solutions, emulsions and pure oil containing small amounts of emulsifiers. Additionally, microwave popcorn and chocolate spread were used to investigate migration. Results indicate that fluorochemicals paper additives do migrate to food during actual package use. For example, we found that microwave popcorn contained 3.2 fluorochemical mg kg^-1 popcorn after popping and butter contained 0.1 mg kg^-1 after 40 days at 4°C. Tests also indicate that common food-simulating liquids for migration testing and package material evaluation might not provide an accurate indication of the amount of fluorochemical that actually migrates to food. Tests show that oil containing small amounts of an emulsifier can significantly enhance migration of a fluorochemical from paper.     

Migration of fluorochemical paper additives from food-contact paper into foods and food simulants

Fluorochemical-treated paper was tested to determine the amount of migration that occurs into foods and food-simulating liquids and the characteristics of the migration. Migration characteristics of fluorochemicals from paper were examined in Miglyol, butter, water, vinegar, water–ethanol solutions, emulsions and pure oil containing small amounts of emulsifiers. Additionally, microwave popcorn and chocolate spread were used to investigate migration. Results indicate that fluorochemicals paper additives do migrate to food during actual package use. For example, we found that microwave popcorn contained 3.2 fluorochemical mg kg^?1 popcorn after popping and butter contained 0.1 mg kg^?1 after 40 days at 4°C. Tests also indicate that common food-simulating liquids for migration testing and package material evaluation might not provide an accurate indication of the amount of fluorochemical that actually migrates to food. Tests show that oil containing small amounts of an emulsifier can significantly enhance migration of a fluorochemical from paper.     

Time‐ and temperature‐dependent migration studies of Irganox 1076 from plastics into foods and food simulants

The study provides an exhaustive set of migration data for octadecyl 3‐(3,5‐di‐tert‐butyl‐4‐hydroxyphenyl)propionate (Irganox 1076) from low‐density polyethylene (LDPE) in several food matrices. Irganox 1076 was used as a model migrant because it represents one of the typical substances used as an antioxidant in food packaging polymers. Kinetic (time‐dependent) migration studies of Irganox 1076 were performed for selected foodstuffs chosen with different physical–chemical properties and in relation to the actual European food consumption market. The effect of fat content and of the temperature of storage on the migration from plastic packaging was evaluated. The results show that migration increased with fat content and storage temperature. All data obtained from real foods were also compared with data obtained from simulants tested in the same conditions. In all studied cases, the kinetics in simulants were higher than those in foodstuffs. The work provides data valuable for the extension of the validation of migration model developed on simulants to foodstuffs themselves.     

Required barrier efficiency of internal bags against the migration from recycled paperboard packaging into food: a benchmark

The use of recycled paperboard and corrugated board for food packaging is in the interest of the sustainability of resources, but in most applications the food must be protected against contamination from these materials, such as by an internal bag with a functional barrier. Producers of packaging need a specification to find the most suitable and economical barrier for a given application, and the customer needs the confidence that a solution offered to him is adequate. An accurate determination of the barrier efficiency is not possible due to the large number of migrants, most of which have not been evaluated or not even identified. Hence the specification must be based on assumptions and verifiable by a simple test. The proposed benchmark presumes that the migration of all non-evaluated or even unknown substances in recycled paperboard will remain below 0.01 mg kg^–1 food, the conventional detection limit, if their transfer does not exceed 1% of the content in the paperboard. Some substances, such as mineral oil or fatty acids, will exceed the 0.01 mg kg^–1 limit, but they are known, evaluated and of no concern at the reduced migration. Since the critical substances must be assumed to be unknown, the criterion of the 1% migration is tested with three surrogate substances of similar volatility and covering a broad range of polarity. The cornerstones of the method are specified.     

Using <Superscript>1</Superscript>H and <Superscript>13</Superscript>C NMR techniques and artificial neural networks to detect the adulteration of olive oil with hazelnut oil

The lack of any official analytical method to detect the adulteration of olive oil with a low percentage of hazelnut oil is explained by the similarities in the chemical compositions of both kinds of oils. To counter this problem, an artificial neural network based on ¹H-NMR and ¹³C-NMR data has been developed to detect olive oil adulteration, and the results from this ANN are presented here. A training set consisting of hazelnut oils, pure olive oils, and olive oils blended with 2–20% hazelnut oils was used to design and train a multilayer perceptron with 100% correct classifications. This mathematical model was also validated using an external validation set of blend samples (3–15%) and genuine samples. The detection limit of the model was around 8%.     

端视ICP-AES法测定食品用塑料包装容器在四种食品模拟物中有害元素迁移量

建立了端视电感耦合等离子体原子发射光谱(ICP-AES)法测定食品用塑料包装容器在4种食品模拟物中有害元素铅、镉、铬、砷、锑和锗迁移量的分析方法。研究了不同食品模拟物试液的处理方法以及仪器工作参数对铅、镉、铬、砷、锑和锗测定信号的影响,消除了乙醇基质的严重抑制干扰,并优化了ICP-AES测定条件。铅、镉、铬、砷、锑和锗的检出限分别为0.0025、0.00023、0.00016、0.0033、0.0032、0.0030mg/L,测定低限:以蒸馏水、3%乙酸、10%乙醇作食品模拟物时分别为0.010、0.0010、0.0010、0.010、0.010、0.010mg/L;以精制橄榄油作食品模拟物时分别为0.020、0.0020、0.0020、0.020、0.020、0.020mg/L。加标回收率在92.0%～98.8%,相对标准偏差在1.69%～7.64%(n=8)。方法灵敏、简便、快速、准确,适用于进出口食品用塑料包装容器中有害元素迁移量的快速测定。     

Updated evaluation of the migration of styrene monomer and oligomers from polystyrene food contact materials to foods and food simulants

Due to the 2011 labelling of styrene monomer as “reasonably anticipated to be a human carcinogen” by the National Institutes of Health’s National Toxicology Program (NTP) and the controversy over whether styrene oligomers mimic the physiological effects of estrogen, an updated review of styrene monomer and oligomers in food and food contact materials (FCMs) was performed. The concentrations of styrene monomer and oligomers were determined in 24 polystyrene (PS) products and ranged from 9.3 to 3100 mg kg^–1 for the styrene monomer, 130–2900 mg kg^–1 for the sum of three styrene dimers, and 220–16,000 mg kg^–1 for the sum of six styrene trimers. Foods in contact with PS packaging had styrene monomer concentrations ranging from 2.6 to 163 ng g^–1; dimer concentrations from the limit of quantitation (LOQ) to 4.8 ng g^–1 and trimer concentrations were all below the LOQ (2 ng g^–1). Diffusion coefficients (D_p) and partition coefficients (K) were also calculated for styrene dimers and trimers. The results presented here indicate that styrene monomer concentrations in foods have not significantly changed since the 1980s and monomer concentrations in food packaging quantified in this study were all below USFDA limits. Although styrene dimers and trimers are present in higher concentrations in PS FCMs than the monomer, their migration to food is limited because of their high K values (4 × 10² to 2 × 10⁶) and their low diffusion coefficients in PS products. Additionally, diffusion coefficients calculated using USFDA-recommended food simulants and Arrhenius plots describing the temperature dependence of styrene dimers and trimers can be used in future calculations of dietary intake of the styrene oligomers.     

Migration of epoxidized soybean oil (ESBO) and phthalates from twist closures into food and enforcement of the overall migration limit

Nineteen samples of food in glass jars with twist closures were collected by the national food inspectors at Danish food producers and a few importers, focusing on fatty food, such as vegetables in oil, herring in dressing or pickle, soft spreadable cheese, cream, dressings, peanut butter, sauces and infant food. The composition of the plasticizers in the gaskets was analysed by gas chromatography with flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Epoxidized soybean oil (ESBO) and phthalates were determined in the homogenized food samples. ESBO was the principal plasticizer in five of the gaskets; in 14 it was phthalates. ESBO was found in seven of the food samples at concentrations from 6 to 100 mg kg^?1. The highest levels (91–100 mg kg^?1) were in oily foods such as garlic, chilli or olives in oil. Phthalates, i.e. di-iso-decylphthalate (DIDP) and di-iso-nonylphthalates (DINP), were found in seven samples at 6–173 mg kg^?1. The highest concentrations (99–173 mg kg^?1) were in products of garlic and tomatoes in oil and in fatty food products such as sauce béarnaise and peanut butter. For five of the samples the overall migration from unused lids to the official fatty food simulant olive oil was determined and compared with the legal limit of 60 mg kg^?1. The results ranged from 76 to 519 mg kg^?1 and as a consequence the products were withdrawn from the market.     

HS-GC/MS method development and exposure assessment of volatile organic compounds from food packaging into food simulants

ABSTRACT

A simultaneous headspace-gas chromatography/mass spectrometry (HS-GC/MS) method was developed and validated to determine the migration of 12 volatile organic compounds (methanol, acetone, methylethylketone, ethylacetate, isopropylalcohol, benzene, toluene, ethylbenzene, xylene, cumene, propylbenzene, and styrene) from food contact materials into food simulants (water, 4% acetic acid, 50% ethanol, and n-heptane). The limits of detection and quantification were 0.007–0.201 mg L^?1 and 0.023–0.668 mg L^?1, respectively. The method was applied to 205 samples of paper/paperboard, polyethylene, polypropylene, polystyrene, and polyethylene terephthalate. The estimated daily intake (EDI) was calculated using the migration results. Exposure assessments were carried out to compare the EDI to the tolerable daily intake (TDI); the results indicated that the EDI of styrene represented only a small percentage (8.0%) of the TDI. This analytical method will be a useful tool to examine levels of various volatile compounds migrating from food packaging to food simulants using HS-GC/MS method.