Determination of 2-alkylcyclobutanones with electronic impact and chemical ionization gas chromatography/mass spectrometry (GC/MS) in irradiated foods

The use of a column containing 60 g of silica gel for cleanup and the use of isobutane as a reactant reagent for chemical ionization-mass spectrometric analysis of the saturated and monounsaturated alkyl side-chain 2-alkylcyclobutanones (2-ACBs; specifically induced by irradiation from fat in foods until the proof of contrary) has improved both the sensibility and the selectivity of the method when applied for the detection of irradiated foods. The quality of the chromatograms obtained was improved, allowing the detection of food samples (avocados) irradiated at low doses (0.1 kGy) or irradiated ingredients included in low proportions (less than 5%, wt/wt) in nonirradiated culinary foods. These analytical modifications for the detection of 2-ACBs on the official EN 1785 method enable an extension of its current field of application using common equipment of food quality control laboratories.     

Thermally generated 3-aminopropionamide as a transient intermediate in the formation of acrylamide

On the basis of the recent findings that "biogenic amines" can also be formed during thermal food processing from their parent amino acids in a Strecker-type reaction, the formation of 3-aminopropionamide, the biogenic amine of asparagine, was investigated in model systems as well as in thermally processed Gouda cheese. The results of model studies revealed that, besides acrylamide, 3-aminopropionamide was also formed in amounts of 0.1-0.4 mol % when asparagine was reacted in the presence of either glucose or 2-oxopropionic acid. Results of a second series of model experiments in which [(13)C(4)(15)N(2)]-asparagine ([(13)C(4)(15)N(2)]-Asn) and unlabeled 3-aminopropionamide were reacted together in the presence of glucose revealed a >12-fold higher efficacy of 3-aminopropionamide in acrylamide generation as compared to asparagine. Both [(13)C(3)(15)N(2)]-3-aminopropionamide and [(13)C(3)(15)N(1)]-acrylamide were formed during [(13)C(4)(15)N(2)]-Asn degradation in a ratio of about 1:4, supporting the idea that 3-aminopropionamide is a transient intermediate in acrylamide formation. In this study, 3-aminopropionamide was identified and quantified for the first time in foods, namely, in Gouda cheese. Although the fresh cheese contained low amounts of 3-aminopropionamide, its concentrations were much increased to approximately 1300 mug/kg after thermal processing. In isotope labeling studies, performed by administering to the cheese [(13)C(4)(15)N(2)]-Asn in a ratio of 1:2 as compared to the "natural" concentrations of asparagine, similar ratios of unlabeled/labeled 3-aminopropionamide and unlabeled/labeled acrylamide were determined. Thus, 3-aminopropionamide could be verified as a transient intermediate of acrylamide formation during food processing.     

Model-based mean adjustment in quantitative germplasm evaluation data

Evaluation data from germplasm collections obtained across many years is often very unbalanced and sparse. For making efficient use of these data, it is desirable to compute summary statistics such as means. The simple arithmetic mean is not a useful measure, because due to the unbalancedness it may yield biased and thus misleading information. Some form of adjustment for diverging environmental effects is therefore needed. In this paper we advocate the use of a simple and well known least squares method to compute adjusted means. The method is exemplified using a published example on wheat (Triticum aestivum L.).     

Removal of Formic Acid from Wastewater using Three-Phase Three-Dimensional Electrode Reactor

A new electrochemical reactor, three-phase three-dimensional electrode reactor, was designed and used to investigate theremoval of formic acid from simulated wastewater. The experimental results were assessed in term of Chemical OxygenDemand (COD) removal efficiency. The results showed that the three-phase three-dimensional electrodes could effectively removeformic acid. Its COD removal efficiency was much higher than those of two-dimensional electrodes and common three-dimensionalelectrodes, respectively. The COD removal efficiency of the three-phase three-dimensional electrodes using air as a spargegas increased 13.5% relative to that using nitrogen as a spargegas. The observation indicated that the sparged air in the three-phase three-dimensional electrodes not only participated insome physical processes but also played an important role in electrochemical reactions to assist COD removal.     

Physiological,morphological, chemical and genomic diversities of different origins of thyme (<Emphasis Type="Italic">Thymus vulgaris</Emphasis> L.)

For the selection of donors with valuable characteristics for breeding, 39 thyme accessions were evaluated in three years according to a staggered schedule. The criteria investigated were: winter hardiness, beginning of flowering, growth height, yield of the dry herb, content of essential oil, composition of the essential oil, DNA content of cell nuclei and number of chromosomes. The most strongly varying traits between the populations were the yield of dry herb, the content of essential oil and the content of volatile phenols with coefficients of variation (CV) between CV 40% and 50%. The largest variation within a population was detected for the yield of dry herb (CV 25–46%) and the content of essential oil (CV 17–48%). The homogeneity of the populations was different. The minimal average coefficient of variation of all traits (CV 19%) was determined in the population of the cultivar ‘Varico II’ and in a population from Lithuania. The ploidy level of T. vulgaris was diploid (2n = 30).     

Coppice management effects on experimentally established populations of three herbaceous layer woodland species

Traditional coppice management creates a temporal release of resources. We determined how this affected three herbaceous species (Cardamine pratensis, Primula elatior and Geum urbanum) and if it was suitable for their conservation within woodland given their differing phenologies and habitat affinities for woodland.Reproductive adults were transplanted and their fate, i.e. survival and counts of leafs and flowers, plus the fate of their progeny, were monitored for three years following cutting of coppice shoots (three light levels) or yearly autumn mowing.Cardamine pratensis and P. elatior produced more flowers with increasing light availability. Mowing increased flower and leaf production with time for P. elatior. Seedling numbers followed a similar trend. Geum urbanum initially produced more flowers with increasing light and when mown, but the effect disappeared and did not increase seedling numbers. Its basal leaves showed the opposite pattern. Population growth rates (λ), calculated for P. elatior and G. urbanum, confirmed the strong treatment effects on the former and the absence of effects on the latter. Yet, decomposition of treatment effects, showed considerable flexibility in life history of G. urbanum, except for contributions of fecundity. The latter, however, contributed most to positive effects on λ for P. elatior.Early flowering species with an affinity for open habitats (C. pratensis > P. elatior) benefited more from temporal resource release than the later flowering, typical woodland species. Coppice management thereby maintains both typical forest herbs and herbs with affinity for more open habitats. This is an important conservation tool especially in intensively managed landscapes.     

Use of an in vitro digestion model to study the bioaccessibility of 4-hydroxy-2-nonenal and related aldehydes present in oxidized oils rich in omega-6 acyl groups

Mixtures of either sunflower oil or thermodegraded sunflower oil and a standard meal were submitted to an in vitro digestion model. The same experiment was carried out with fluid deep-frying fat and thermodegraded fluid deep-frying fat. The thermodegradation of the oil and fat was provoked by submitting them to 190 degrees C with aeration in a convection oven, and the presence in the headspace of the thermodegraded oil and fat of oxygenated alpha,beta-unsaturated aldehydes (OalphabetaUAs), such as 4-hydroxy-2-nonenal (HNE), 4-oxo-2-nonenal (ONE), and 4,5-epoxy-2-decenal (EDE), was monitored by solid phase microextraction (SPME) followed by gas chromatography-mass spectrometry (GC-MS). The digestion products were separated by centrifugation in a lipidic phase, an aqueous phase, and a pellet phase. The headspace of these three phases was also studied by SPME/GC-MS to check if the toxic and very reactive OalphabetaUAs above-mentioned remained unaltered after the in vitro digestion process or if they had reacted with the various compounds present in the digestion products, so disappearing from the samples. With the same aim the extract in ethyl acetate of the aqueous and pellet phases, and of the lipidic phase after dilution, were studied by GC-MS. All results obtained showed that a certain proportion of the toxic OalphabetaUAs remains unaltered after digestion, dispersed in the three phases above-mentioned, and thus are bioaccessible in the gastrointestinal tract and so could reach the systemic circulation. Compounds that may originate in Maillard type reactions (2-pentylpyridine) are found among digestion products, proving that these reactions are possible in this process if adequate substrates are present. In addition, it has been shown that toxic metabolites from the synthetic antioxidant BHT, present in fat before digestion, remain unaltered after this process and could reach the systemic circulation.