J.M. Cruz

Kinetic migration studies from packaging films into meat products

One of the main concerns regarding safety of food packaging is the possible migration of chemical substances (monomers and other starting substances, additives, residues) from food contact materials into foods. To evaluate the effect of the fat content and of the temperature of storage on the migration from plastics packaging films into meat products as an important class of foodstuffs, the kinetic mass transport of a model migrant (diphenylbutadiene) from low density polyethylene (LDPE) film in contact with different meat products was investigated. From the data, the diffusion coefficients were calculated for the applied test conditions, by use of a mathematical model. The results showed that migration increased with fat content and storage temperature. Analysis of migration data corresponding to minced pork meat containing different amounts of fat, stored for 10 days at 25°C, revealed an excellent relationship between migration level and fat content. This behaviour was also found for other types of meat products (chicken and pork neck). A simplifying mathematical model was applied to derive effective diffusion coefficients in the polymer which, however, do take kinetic effects in the meat also into account. In the case of pork meat contact, the effective diffusion coefficients derived from mathematical modelling were ten times higher for storage at 25°C (1.88×10(-9)cm(2)s(-1)) than for storage at 5°C (1.2×10(-10)cm(2)s(-1)).

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.

Antioxidants from barley husks impregnated in films of low‐density polyethylene and their effect over lipid deterioration of frozen cod (Gadus morhua)

BACKGROUND The changes in quality of cod fillets packaged in films with and without antioxidants during 12 months of frozen storage at - 20 °C were investigated in the present study. The following parameters were determined in order to study lipid hydrolysis and primary and secondary lipid oxidation in the samples during frozen storage: peroxide value, conjugated dienes, conjugated triene hydroperoxides, free fatty acids, totox value, thiobarbituric acid-reactive substances and p-anisidine value. RESULTS Films containing antioxidants isolated from barley husks were effective in slowing down lipid hydrolysis and primary and secondary lipid oxidation processes. Secondary lipid oxidation reached maximum values in the 12th month of storage in control samples and samples packaged with antioxidant-containing film. Maximum lipid hydrolysis and lipid oxidation values for control cod samples were significantly higher than the maximum values found in samples packaged with antioxidant-containing film. CONCLUSION The results confirm the efficacy of natural antioxidants derived from barley husks in slowing down lipid hydrolysis and increasing the oxidative stability of cod flesh. They also demonstrate the potential usefulness of natural antioxidants extracted from barley husks in the development of active packaging films for food preservation.

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.