P. Paseiro-Losada

Determination of bisphenol A in, and its migration from, PVC stretch film used for food packaging

Bisphenol A (BPA) is used as an additive in polyvinyl chloride (PVC) products, including stretch films used for food packaging. The BPA contents were investigated of several brands of stretch film bought locally but marketed internationally or throughout Spain and which were presumably produced at different manufacturing plants. Their major components were identified by FTIR (Fourier Transform Infrared Spectrometry) and horizontal attenuated total reflectance, and the migration of BPA from these materials into the standard European Union food simulants was determined by high-performance liquid chromatography (HPLC) using both fluorescence (FL) and ultraviolet (UV) detection, the identity of the analyte being confirmed by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS). The two HPLC detection methods had different detection limits (30 µg l−1 for UV, 3 µg l−1 for FL), but afforded virtually identical BPA determinations for the samples tested. BPA contents ranging from 40 to 100 mg kg−1 were found in three of the five PVC-based films analysed, and a content of 500 mg kg−1 was found in a fourth; for these determinations, extraction into acetonitrile was used. In standard tests of migration into water, 3% acetic acid and olive oil over 10 days at 40°C, migration from a given film was in all cases greatest into olive oil. Migration from the films with non-zero BPA contents ranged from 3 to 31 µg dm−2, values higher than those reported for many other food-contact materials, but lower than the European Union specific migration limit for BPA. PVC stretch film nevertheless may make a significant contribution to contamination of foodstuffs by BPA, and should be taken into account in estimating BPA intake or exposure to this substance.

High-performance liquid chromatographic determination of α-tocopherol in macroalgae

Abstract A high-performance liquid chromatographic (HPLC) method for the microscale determination of α-tocopherol in macroalgae is reported. The method includes microscale saponification and extraction with n -hexane. The presence of α-tocopherol in macroalgae samples was confirmed by HPLC–MS. α-Tocopherol levels as determined in samples by HPLC with UV and fluorescence detection did not differ significantly; however, fluorescence detection has a higher sensitivity (detection limit 10.4 ng/ml, vs. 104 ng/ml with UV detection), as well as good precision (relative standard deviation 1.81%) and recovery (94.3%). Fluorescence detection is also faster. We used this method to determine the α-tocopherol contents of four commercial macroalgae products from northwest Spain as part of nutritional studies in dehydrated Himanthalia elongata and Laminaria ochroleuca , and also in canned Himanthalia elongata and Saccorhiza polychides.

Development of new active packaging films coated with natural phenolic compounds to improve the oxidative stability of beef

The aim is to develop active packaging films containing natural antioxidants and to evaluate their capacity to enhance the oxidative stability of beef during refrigeration. The antioxidant activity of a natural extract obtained from a brewery residual waste was evaluated and compared with that of a commercial rosemary extract and two synthetic antioxidants (BHT and propyl gallate). Different concentrations of each antioxidant were also added directly to beef samples, resulting in a reduction in lipid oxidation of up to 70-80% relative to the control. Active antioxidant films coated with PVPP-WS extract reduced lipid oxidation by up to 80%, relative to the control, during cold storage. The use of active packaging films containing natural extracts could improve the oxidative stability of meat products and should therefore be of great interest in the food industry.

Development of a Method To Study the Migration of Six Photoinitiators into Powdered Milk

The aim of the present work was to develop a rapid multimethod for the analysis of six photoinitiators (PIs) in powdered milk and to study the migration of these PIs from LDPE packaging into powdered milk. The optimized HPLC-DAD method showed high correlation coefficients (>0.9999) over a concentration range of 0.1-10.9 mg/L. The kinetics of migration of the photoinitiators from LDPE packaging into powdered milk were determined at different temperatures. The key parameters of migration phenomena (diffusion and partition coefficients) were determined. The diffusion coefficients at 5 degrees C ranged between 8.4 x 10(-12) (for ITX) and 5.1 x 10(-10) (for benzophenone) and those at 40 degrees C between 5.9 x 10(-10) (for ITX) and 6.1 x 10(-9) (for Irgacure 184). The diffusion coefficients of the six model migrants under study increased with temperature and showed a good Arrhenius relationship between 5 and 40 degrees C.

Study of the migration of photoinitiators used in printed food-packaging materials into food simulants.

Photoinitiators (PIs) are used as catalyzers for inks and lacquers that are cured with ultraviolet (UV) light, and they can contaminate foodstuffs by mass transference.The aim of the present paper is to study the migration of six photoinitiators (Irgacure 184, benzophenone, Irgacure 651, Irgacure 907, ITX, and EHA) into food simulants [distilled water, 3% acetic acid (w/v) in aqueous solution, 10, 20, 30, 60 and 95% ethanol (v/v) in aqueous solution]. Migration levels of the six PIs into different food simulants were compared after a 30 day contact period with the additivated plastic. A relationship between R (ratio between log K(o/w) and MW) and total migration was found for PIs with log K(o/w) < 5. Key parameters of migration processes were calculated according to a mathematical model based on Ficks second law. Diffusion (D) and partition coefficients were estimated and compared among different simulants, temperatures, and PIs to understand better the mechanisms of the migration process and the physicochemical properties that most influence this phenomenon. For instance, at 5 degrees C, in ethanol 95% (v/v), D ranged between 4.2 x 10(-11) cm/s for Irgacure 907 and 3.0 x 10(-9) cm/s for benzophenone.

Development of an Analytical Method for the Determination of Photoinitiators Used for Food Packaging Materials with Potential to Migrate into Milk

Photoinitiators are used in the curing process during UV printing of food carton labels. The alarm concerning the detection of a photoinitiator, 2-isopropyl thioxanthone (ITX), in food samples packed with cartons printed with UV-cured inks has focused the attention of legislative authorities on the potential migrants from packaging inks into foods. For this reason it is very important to carry out analytical methods for the detection of those compounds in food as potential migrants from packaging. The aim of the present work was to develop a multimethod for the analysis of 6 photoinitiators in milk. The selected photoinitiators were Irgacure 184, benzophenone, Irgacure 651, Irgacure 907, Quantacure ITX, and Quantacure EHA (2-ethylhexyl-4-dimethylaminobenzoate). Milk (10 mL) extraction was carried out by using ammoniac and hexane. The supernatant was evaporated and the residue was redissolved with acetonitrile. Then, the extract was analyzed by HPLC-UV. Calibration lines were carried out over the concentration range of 0.1 to 10 mg/L. The calibration data presented high correlation coefficients (>0.9999). Mean recoveries (n = 6) of the 6 photoinitiators were 83.4% (residual standard deviation = 2.3%) at 0.5 mg/kg and 81.0% (residual standard deviation = 4.6%) at 1 mg/kg. Several milk samples and their respective packaging cartons were analyzed. Results were confirmed by HPLC-mass spectrometry.

Brewery waste as a potential source of phenolic compounds: Optimisation of the extraction process and evaluation of antioxidant and antimicrobial activities

This paper reports the development of an extraction process that allows selective recovery of polyphenols from a brewery waste stream. The antioxidant activity of this extract (EC50 = 0.23-0.3g/L) was very high, similar to that of butylated hydroxyanisole (BHA) and higher than that of other synthetic antioxidants such as butylated hydroxytoluene (BHT). Crude extracts exhibited a high level of antimicrobial activity against Gram-positive and Gram-negative bacteria, when applied at concentrations of 1% and 3% (w/v). The antioxidant and antimicrobial activities can probably be attributed to the major phenolic compounds, such as protocatechuic, caffeic, p-coumaric and ferulic acids and catechin. With this procedure, the waste polyphenols could be used as cheap source of natural compounds, with potential applications in the food and health sectors. Substitution of synthetic additives with safe and effective natural additives may be of further benefit to the food industry.

Migration of Photoinitiators by Gas Phase into Dry Foods

Photoinitiators are components widely used in UV-cured inks for printing food packaging. In the present study, the migration of seven photoinitiators through the vapor phase was investigated. To perform the migration test, an additive enriched polyethylene wax was used as a source to release photoinitiators. The method was applied to evaluate the migration of the photoinitiators into five selected dry foods (cake, bread, cereals, rice and pasta). The highest level of migration was found in the cake. Parameters affecting the migration process were evaluated, and high migration level was found to correlate with both the porosity and the fat content. In addition, the kinetics of migration of the photoinitiators from the additive enriched wax into the cake were studied under accelerated conditions.

Development of a Multimethod for the Determination of Photoinitiators in Beverage Packaging

Photoinitiators are ink components used in the printing of food packaging. The aim of the present study was to develop a multimethod for the analysis of photoinitiators in paperboard packages and commercial beverage packages. The proposed method is simple and fairly rapid. Extraction is carried out with acetonitrile. A reverse-phase high performance liquid chromatography (HPLC) method with UV detection was developed to quantify the 6 selected photoionitiators. Total HPLC time analysis was 30 min and the flow-rate was 1 mL/min. Method validation parameters such as linearity and detection limit are reported. Recovery of all photoinitiators (at 1 mg/kg) from orange juice was satisfactory (mean = 88.4%; ranging from 84.6% to 93.4%). Recovery of benzophenone and Irgacure 651 was good (ranging from 85.2% to 98.1% and 86.1% to 92.2%, respectively) at the 4 concentrations studied (0.1, 0.2, 0.5, and 1 mg/kg). Commercial beverage packages were analyzed and when photoinitiators were detected, the beverages were also analyzed.

Fractionation and Purification of Bioactive Compounds Obtained from a Brewery Waste Stream

The brewery industry generates waste that could be used to yield a natural extract containing bioactive phenolic compounds. We compared two methods of purifying the crude extract—solid-phase extraction (SPE) and supercritical fluid extraction (SFE)—with the aim of improving the quality of the final extract for potential use as safe food additive, functional food ingredient, or nutraceutical. The predominant fractions yielded by SPE were the most active, and the fraction eluted with 30% (v/v) of methanol displayed the highest antioxidant activity (0.20u2009gu2009L−1), similar to that of BHA. The most active fraction yielded by SFE (EC50 of 0.23u2009gu2009L−1) was obtained under the following conditions: temperature 40°C, pressure 140u2009bar, extraction time 30 minutes, ethanol (6%) as a modifier, and modifier flow 0.2u2009mLu2009min−1. Finally, we found that SFE is the most suitable procedure for purifying the crude extracts and improves the organoleptic characteristics of the product: the final extract was odourless, did not contain solvent residues, and was not strongly coloured. Therefore, natural extracts obtained from the residual stream and purified by SFE can be used as natural antioxidants with potential applications in the food, cosmetic, and pharmaceutical industries.