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Abstract:The in vitro radical scavenging capacity of the roasted and ground coffee is generally known as well as the published results of lowering the incidence of various diseases by regular intake of coffee. The antioxidant capacity of coffee is based mainly on the phenols, but during the roasting phenols are degraded and new products with antioxidant capacity are formed. A major contributor to the antioxidant activity was identified as N-methylpyridinium, which is formed during the roasting by degradation of trigonelline, the degradation is about 50% of trigonelline content and the concentration of N-methylpyridinium in roasted coffee is up to 0.25% on a dry weight basis. These literature data were verified within the processing plant experiment, during the usual roasting procedure of Robusta coffee the following parameters were analysed: humidity, water activity, total antioxidant capacity, total phenols, chlorogenic acid and trigonelline content, and colour (L*, a*, b*). The changes of the evaluated parameters were correlated to each other. During the roasting the total antioxidant capacity (TAC) decreased to about one half of original level in the beginning stages of roasting, another decrease continued during the storage of roasted coffee at about 10% within the year. The degradation of trigonelline, neither the content of chlorogenic acid or total phenols did not correlate with TAC in samples during the roasting and storage.

Residues of printing ink components were determined in 94 samples of packaging materials commercially used in the Czech Republic for food packaging. The samples tested included printed polyethylene and polypropylene films, co-extruded and laminated films, paperboard beverages boxes, foils for thermo sealing of polystyrene cups, and polypropylene cups. Printing ink components were extracted with diethylether, then separated and determined using gas chromatography-mass spectrometry (GC/MS). Fifty compounds potentially originating from printing were isolated, identified and quantified. No acute health risk for consumers were identified, even though several findings of high levels of photo-initiators (e.g. in polyethylene terephthalate (PET) films for thermo sealing of polystyrene cups) as well as plasticizers (acetyl tributyl citrate, tributyl aconitate, 2-butoxyethyl oleate and 2-ethylhexyl diphenyl phosphate in co-extruded films) indicate that their real migration into food and/or food simulants needs to be undertaken for a proper safety evaluation.

Votavová L., Dobiáš J., Voldřich M., Čížková H. (2009): Migration of nonylphenols from polymer packaging materials into food simulants. Czech J. Food Sci., 27: 293-299.p-Nonylphenol (NP) is widely used in many industrial applications (detergents, latex paints, pesticides, and plastics), and its presence in the environment has acquired an increasing concern since it was shown to be, besides its persistence and toxicity, an estrogenic compound. Seven samples of stretch PVC films and two PVC dishes for food packaging obtained from food producers were analysed for the presence of NP. Four of the PVC films contained NP at the concentrations of 0.44 mg/g, 1.03 mg/g, 1.28 mg/g, and 1.72 mg/g, respectively, while NP was not detected (the detection level being 5 µg/g) in the remaining films and two dishes. The NP positive films were used for the studies of NP migration into the food simulants. The levels of NP migration into the food simulants: distilled water, 3% acetic acid solution, and 95% ethanol were 0.017-0.091 mg/g (3.2-5.3%), 0.013-0.079 mg/g (2.9-4.6%), and 0.125-0.449 mg/g (21.5-35.0%), respectively. The potential safety risks estimated from the results obtained as well as the possible sources of the NP contamination in the analysed stretch PVC food films are discussed in the following article.

Epoxidised soybean oil (ESBO) is widely used as a plasticiser and stabiliser mainly in food contact materials on the base of polyvinylchloride (PVC), especially in the gaskets of jar lids. PVC gaskets containing 10-37% of ESBO were prepared by the baking of PVC plastisols at various process temperatures (180-240°C) in the laboratory. ESBO migration into olive oil and 3% acetic acid was studied at various temperatures (4°C, 25°C, 40°C and 60°C) during a storage time up to 12 months. ESBO released into food simulants was transmethylated, derivatised and analysed by gas chromatography-mass spectrometry (GC/MS). The effect of food processing, i.e. pasteurisation (80°C and 100°C) and sterilisation (125°C) on ESBO migration was also evaluated. The results were critically assessed with respect to the test conditions of specific migration in accordance with the current European Union legislation (Regulation (EU) No. 10/2011). The levels of ESBO migration found confirmed that the test conditions (i.e. 40°C or 60°C, 10 days) representing contact in the worst foreseeable use scenario seem to be insufficient for the simulation of ESBO migration during long-term storage and thus do not provide satisfactory objective results.