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- Measurement of oxygen transmission rate through foamed materials for bottle closuresPublication . Poças, Maria F.; Ferreira, Belmiro; Pereira, Joel; Hogg, TimThe determination of the oxygen transmission rate (OTR) through closures in glass bottles is becoming increasingly important for quality control of different batches and for development purposes. The Mocon method for measuring OTR is globally accepted and used in different applications. However, one of the major drawbacks this method presents when applied to bottle/closures systems is the long time required to obtain stable measurements when 40 mm long closures are tested. This paper describes a method to obtain OTR values with samples of reduced thickness with much shorter measurements time, since the condition of steady state during measurements is achieved faster and compares the estimated full-length commercial closure OTR with experimental values
- Effect of non-thermal processing on the aromatic profile of Cantaloupe melon juicePublication . Georgiev, Radoslav; Pereira, Joel; Fundo, Joana F.; Miller, Fátima A.; Brandao, Teresa R.S.; Chalova, Vesela I.; Silva, Cristina L. M.
- Performance of wine bag-in-box during storage: loss of oxygen barrierPublication . Fradique, S.; Hogg, T.; Pereira, J.; Poças, M .F. F.Bag-in-box system is a convenient packaging system for wine. Its barrier to oxygen relies, in many cases, in an aluminium metallized polyester film laminated between two polyethylene (PE) layers as the inner bag. One on the most frequently observed system failures is the ingress of wine into the gap between the layers of the double bag. This study aimed at verifying if that influences the barrier of the system to oxygen. The results showed that the contact of wine with this barrier layer, although through a PE layer, promotes the demetallization and consequent loss of barrier properties. The type of wine, in particular its volatile acidity, and the temperatures were two variables assessed. Results showed that wine with higher acidity and stored at higher temperatures tend to yield a higher increase in oxygen transmission rate of the film.
- Migration of two antioxidants from packaging into a solid food and into TenaxPublication . Reinas, I.; Oliveira, J.; Pereira, J.; Machado, P.; Poças, M. F.The migration of chemicals from packaging materials into foods is an important issue in food safety and quality. European legislation sets specific migration limits which compliance must be assessed, surveyed and controlled by industry and authorities. Recently, the new Regulation UE 10/2011 included a new simulant - the Modified Polyphenylene Oxide (Tenax ) for solid dry foods. The objective of this work was to compare the migration kinetics of two antioxidants into Tenax as compared to rice at 3 temperatures: 23, 40 and 70 C. The application of two different solutions of the 2nd Fick’s law to describe and simulate the migration of the migrants to the present systems was studied. Diffusion coefficients ranged between 4.80E-13 and 2.84E-11 cm2/s for the migration into Tenax and between 6.90E-18 and 4.33E-17 cm2/s for the migration into rice. The partition coefficients ranged between 6 and 29 for Tenax and were over 1000 for rice. The activation energy for the migration into rice was half of that for Tenax . The models described relatively well the experimental data (ε < 12% and < 30% for rice and Tenax , respectively). Results indicate that the food simulant tends to overestimate migration values and thus can be safely used to assess materials compliance when materials are intended to contact with rice. However, results also indicate that Tenax is a much more severe simulant in representing rice.
- Photoinitiators use in printed baby bibs and their migration into Tenax® by gas chromatography–mass spectrometryPublication . Galbiati, Edoardo; Pereira, Joel; Selbourne, Maria do Céu; Poças, FátimaA simple and accessible gas chromatography–mass spectrometry method was developed to determine photoinitiators (PIs) in plastics for food contact and their migration into Tenax®. The method showed analytical performance suitable for compliance assessment. The limit of detection values found were as follows: for benzophenone and 4‐(4‐morpholinyl)benzaldehyde ~3 μg kg−1 food (6 dm2 kg−1 food), for 4‐methylbenzophenone and ethyl‐4‐(dimethylamino)‐benzoate ~1.5 μg kg−1 food and for 2‐ethylhexyl 4‐(dimethylamino)benzoate ~43 μg kg−1 food. For all the other PIs studied, limits of detection lower than 1 μg kg−1 food were found. The method was applied to analyse samples of plastic baby bibs collected in European market. Results indicate that several unauthorised PIs are in use to print bibs. The most commonly detected PIs were benzophenone detected in nearly all samples and isopropylthioxanthone quantified in 12 out of 22 samples. Several non‐evaluated PIs were detected: triphenyl phosphate, 2‐ethylanthraquinone, 2,2‐dimethoxy‐2‐phenylacetophenone, 4‐(4‐methylphenyltio)benzophenone, 1‐hydroxycyclohexyl phenyl ketone and 4,4′‐bis(diethylamino)‐benzophenone. These two latter PIs were found at the highest concentration (more than 100 μgg−1). Testing a selection of samples for migration into Tenax® gave results exceeding the applicable migration limit for 1‐hydroxycyclohexyl phenyl ketone with 0.532 mg kg−1 (specific migration limit = 0.01 mg kg−1) and for methyl 2‐benzoylbenzoate with 0.182 mg kg−1 (specific migration limit = 0.05 mg kg−1). Although the results may be affected by a certain overestimation degree given the experimental conditions, they certainly flag an area of potential interest for surveillance and more detailed risk evaluation, particularly because bibs are often not seen by industry as food contact materials, and surveillance actions are not systematically acted.
- Consumer exposure to phthalates from paper packaging: an integrated approachPublication . Poças, M.F.; Oliveira, J.C.; Pereira, J.R; Hogg, T.This paper presents an integrated approach to estimate the exposure of the Portuguese population to phthalates as a contaminant originating from paperboard packaging. The approach combined data of migrant concentration in the foods resulting from a stochastic simulation with consumption data of food packaged in paperboard. The results from the exposure model were validated with experimental values actually found in the food. A short surveillance exercise was conducted with samples collection from market shelves to identify and quantify the phthalates present in both the packages and the food. The distribution of values for the di-butyl phthalate concentration in the packages was used as the input of the initial concentration in the Weibull model to estimate the concentration of this phthalate in the foods. This distribution of occurrence data was then combined with the packaging usage data in a probabilistic simulation with a Monte Carlo sampling method. Exposure values ranged between zero and 8.95 mg day 1 kgbw, a value close to the tolerable daily intake established by the European Food Safety Authority (EFSA) – 10 mg day 1 kgbw. However, the 97.5th percentile and the average were 1.82 and 0.44 day 1 kgbw, respectively, indicating that further refinement of the estimates is not necessary. Other phthalates were also detected in the packaging samples: di-isobutyl phthalate and di-ethylhexyl phthalate. The latter was present in all packaging samples collected and was detected in a few food samples at values requiring further investigation.
- Assessment of baby Bibs. GC-MS screening, migration into saliva and insight of toxicity with QSAR toolsPublication . Rajbux, Chandisree; Pereira, Joel; Selbourne, Maria do Céu; Costa-Pinto, Ana Rita; Poças, FátimaPlastic baby Bibs are, according to the European legislation, food contact materials. Therefore, compositional and migration limits applicable to plastics should be observed. This work aimed at identifying potential migrants in Bibs from European market and determining the migration into artificial saliva. Bibs were subjected to screening analyses (GC-MS). Thirty substances non-authorised in European or Swiss legislation were detected: phthalates, light stabilizers, flame retardants and photoinitiators. Irgacure 184, Cyclohexanone, Tinuvin 770, Isophorone and 9-Octadecenamide, (Z)- were detected in saliva after contact with selected Bibs. The migration values render two samples noncompliant although results should be interpreted with caution given the experimental conditions. In order to gain insight on the toxicity of migrants, QSAR tools were applied. Substances non-evaluated or not-listed were analysed with free software regarding their Cramer class (ToxTree and their predicted mutagenicity, carcinogenicity and developmental toxicity (VEGA). Results indicate that surveillance is required: monitoring Bibs'compliance, application of GMPs and traceability.
- A quantitative approach to assess the contribution of seals to the permeability of water vapour and oxygen in thermosealed packagesPublication . Reinas, Isabel; Oliveira, Jorge; Pereira, Joel; Mahajan, Pramod; Poças, Maria de FátimaShelf-life of many foods is largely dependent on the barrier to moisture and oxygen of the respective package. Barrier is often assessed by measuring the transmission rate of films. However, in thermosealed packages leaks and weak seals can give rise to increased total mass transfer entering the system and reaching the food. While leaks are random defects and are associated to early failure, lower integrity of regular seals tends to affect whole batch causing a decrease in the product shelf-life. In the present work the contribution of the seals to total permeability of packages was assessed by measuring transmission rate of the film and of thermosealed packages of different sizes, therefore with different seals length. Packages made of PA/PE and PVDC coated PET/PE and their respective films were tested for moisture and oxygen transmission rate at different temperature and relative humidity. Results indicate that industrial regular produced seals can account for ca. 25% of the total mass transfer through the system. This decrease of the package barrier as compared to the material barrier will have a significant impact on the product shelf-life and it should be considered in the packaging design process.
- Modelling migration from paper into a food simulantPublication . Poças, Maria de Fátima; Oliveira, Jorge C.; Pereira, Joel R.; Brandsch, Rainer; Hogg, TimThe migration of components from paper into Tenax (R) was studied to determine the influence of molecular size and chemical character of the migrant and the influence of paper characteristics in the migration process The Weibull model was applied because Fick s 2nd law of diffusion gave poor fits in some cases The migration pattern depended on the migrants molecular size and was independent of temperature in the studied range The migration rate decreased with the migrant molecular size The influence of the migrants character (polarity and vapour pressure) on the migration behaviour was also studied nonpolar migrants with high vapour pressure presented low relative migration values and polar migrants presented high values of relative migration Results indicated that the apparent partition coefficient between paper and the simulant Tenax (R) increased with the migrant vapour pressure and with both the paper grammage and the recycled pulp content
- Determination of phthalates in olive oil from European marketPublication . Pereira, Joel; Selbourne, Maria do Céu; Poças, FátimaPhthalates are ubiquitous contaminants in the environment and consumer products. They are used as plasticizers in many plastics used for packaging and articles for food processing, handling and storage. Some phthalates and their metabolites are known to be toxic to reproduction and endocrine disruptors, and consumer exposure has been a concern. Olive oil is of great nutritional and economic importance and its contribution to overall dietary exposure to phthalates may be relevant. This work aimed at analysing phthalates occurrence in olive oil samples collected in the European market. An alternative method for sample introduction into the chromatographic system was compared to the traditional liquid extraction followed by concentration prior analyses. The ChromatoProbe method presented similar performance regarding the limits of detection and quantification but, contrary to other matrixes like wine, does not eliminate the need for prior liquid extraction. The main advantage relies on not requiring the concentration step and on decreasing the system stoppages for maintenance. Regarding the olive oil samples collected, DEHP and DINP were detected in all samples with an average concentration of 1.31 and 1.52 mgkg(-1) and with a highest concentration of 7.52 and 6.29 mgkg(-1), respectively. Results show 4/16 samples with DEHP concentration higher than the migration limits applicable under food contact materials regulation. One of the samples is pomace oil and therefore the source of contamination may well be the solvent used in the extraction process. But the other 3 samples are extra-virgin and virgin olive oils. So it is still important to develop efforts in tracing back the source of contamination.