The influence of brewing method on bioactive compounds residues in spent coffee grounds of different roasting degree and geographical origin

The content of bioactive compounds in spent coffee grounds (SGC) was studied. SGC were obtained from Coffea arabica beans of different roasting degrees (light and dark) and different geographical origins (Nicaragua, Columbia and Mexico) processed using four brewing methods (mocha, filtered, drip and infusion). The highest caffeine and chlorogenic acid contents were determined in filtered spent coffee extracts. All extracts of light roasted spent coffee grounds showed lower browning index levels in comparison to that from dark roasted spent coffee grounds. Generally, the highest content of total polyphenolic compounds and highest antioxidant capacity were determined in extracts prepared in drip. In conclusion, the results obtained in this study indicate that the spent coffee grounds produced of domestic levels, especially those obtained from filter coffeemaker, could be considered as a good source of natural antioxidants.     

Differences in two-dimensional gel electrophoresis patterns of skeletal muscle myosin light chain isoforms between Bos taurus, Sus scrofa and selected poultry species

BACKGROUND: In this study the interspecies differences in two‐dimensional electrophoresis patterns of skeletal muscle myosin light chain (MLC) isoforms between Bos taurus (cattle), Sus scrofa (pig), Gallus gallus (chicken), Meleagris gallopavo (turkey), Anas platyrhynchos (duck) and Anser anser (goose) were characterised on the basis of specific properties of MLCs associated with their structure and mobility in gel. RESULTS: Two‐dimensional electrophoresis separations revealed species‐specific differences in the molecular weight and pI of individual MLC isoforms (MLC1f, MLC2f and MLC3f). In the case of closely related animal species such as goose and duck or turkey and chicken, significant differences occurred in MLC1f. For MLC2f, differences between cattle and turkey and between pig and chicken were around 1 and 0.3 kDa respectively. It appeared from the comparison of amino acid sequences that even MLCs with only 2% difference in sequences have different electrophoretic mobilities. CONCLUSION: Interspecies differences in skeletal MLC isoforms appeared between cattle, pig, chicken, turkey, duck and goose. The slight changes observed in the course of the aging process confirmed that these proteins are relatively little susceptible to proteolytic enzymes during meat aging. Copyright © 2011 Society of Chemical Industry     

Strain-specific polyketide synthase genes of Aspergillus niger

In silico comparison of 34 putative pks genes in Aspergillus niger strain CBS 513.88 versus A. niger strain ATCC 1015 genome revealed significant nucleotide identity (>95% covering a minimum of 99% of the gene sequence) for 31 of these genes (approximately 91%). A. niger CBS 513.88 harbors three putative pks genes (An01g01130, An11g05940, and An15g07920), for which nucleotide identity was not found in A. niger ATCC 1015. To compare the results of the in silico analysis with the in vivo situation, experimental data were obtained for a large number of A. niger strains obtained from different substrates and geographical regions. Three putative pks genes that were found to be variable between the two A. niger strains using bioinformatics tools were in fact strain-specific genes based on experimental data. The PCR amplification signals for the An01g01130, An11g05940, and An15g07920 pks genes were detected in only 97%, 71%, and 26% of the strains, respectively. Southern blot analyses confirmed the PCR data. Because one of the strain-specific pks genes (An15g07920) is located in a putative ochratoxin cluster, we focused our investigation on that region. We assessed the ochratoxin production capability of the 119 A. niger strains and found a positive association between the presence of this pks gene and the capability of the respective strain to produce ochratoxin.     

Dual effect of free and liposomal forms of phenolic lipids on the activity of GPI-anchor-deprived acetylcholinesterase from erythrocytes

The effect of free and liposomal forms of phenolic lipids isolated from rye grains, cashew nut-shell liquid (CNSL) from Anacardium occidentale, and Merrulius tremellosus fruit body on the glycosyl-phosphatidylinositol (GPI)-anchor-deprived erythrocyte-ghost acetylcholinesterase activity was studied. It was shown that the observed effect distinctly depends on the form of the phenolic lipids available for interaction with the enzyme. The free form of the phenolic lipids decreased the enzymatic activity of GPI-anchor-deprived acetylcholinesterase less than the acetylcholinesterase anchored in erythrocytes ghosts, whereas the same phenolic lipids present in the medium in liposomal form, increased it.     

Evaluation of QuEChERS method for the determination of organochlorine pesticide residues in selected groups of fruits

This paper reports a method for organochlorine pesticide determination in selected fruit species where pesticide residues were extracted and cleaned using a buffered QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method, followed by GC–MS analysis. The method results showed the matrix-matched calibration curve linearity was >0.99 for all target analytes. With pesticide recovery rates (spiked at 0.008 mg kg⁻¹) ranging from 70% to 120%, and RSD values <17% for most compounds, the limit of quantification ranged from 0.001–0.013 mg kg⁻¹. Finally, the method ruggedness was further demonstrated by analysis of actual commercial fruits and baby food samples.     

The application of d-SPE in the QuEChERS method for the determination of PAHs in food of animal origin with GC–MS detection

This paper reports the evaluation of the Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method for the determination of polycyclic aromatic hydrocarbons (PAHs) in food of animal origin with GC–MS detection. Although in the available literature, there is a lot of information about sample preparation method for PAHs determination in food samples, but the QuEChERS method application for PAHs determination in food of animal origin has not been reported as yet. The results showed that the best recovery ratios 72.4–110.8 % with relative standard deviation lower than 10 % for all determined compounds were received for the method with ethyl acetate as an extraction solvent, primary–secondary amine and C₁₈ sorbents and evaporation to dryness and dissolving the residues in the hexane. The limit of quantification ranged from 0.0003 to 0.0030 mg kg^?1 for pyrene and benzo[a]anthracene, respectively. This method was also used for the determination of PAHs in 15 samples of pork ham. In 8 of 15 samples selected, PAHs were identified. It was observed that in 6 cooked ham and one smoked and cooked samples, any PAHs were found. In other samples, which were smoked and roasted, some low concentration of PAHs was detected. In one sample benzo[a]pyrene (0.0015 mg kg^?1), in one sample benzo[b]fluoranthene (0.0015 mg kg^?1) and in one sample chrysene (0.0024 mg kg^?1) were detected. A number of other less harmful PAHs were also determined. There were no exceedances of maximum levels (according to Commission Regulation (EU) No 835/2011) for determined PAHs in any of the analysed samples.     

Microstructure and instrumentally measured textural changes of rainbow trout (Oncorhynchus mykiss) gravads during production and storage

BACKGROUND: Gravad fish belong to a group of low‐processed products obtained from fresh fish by rubbing fillets with a mixture of sugar and salt and then placing them in cold storage. Little is known about changes in the tissue during the production and storage of gravads. The aim of the present study was to investigate the microstructural and textural changes in rainbow trout (Oncorhynchus mykiss) gravad during processing and vacuum storage at 3 °C and ?30 °C. RESULTS: Microscopic observations of gravad showed greater compactness of structure when compared with raw trout muscle, characterised by the disappearance of the divisions between adjoining myofibrils in gravad. Freezing, on the other hand, caused the myofibrils to again become more clearly distinguishable despite being partly agglomerated into lamellae. The above changes in structure were accompanied by changes in the textural and rheological properties of the product. It was observed that the texture profile (TPA) changed, resulting in an increase in the cohesiveness and chewiness of the gravads when compared to the raw fillets. There was also a lowering of stress decay during the relaxation test and a decrease in the value of the storage modulus (G′) as analysed by oscillatory rheometry. Further changes observed during storage were mainly concerned with an increase in the hardness and chewiness of gravads. CONCLUSION: Gravading significantly changes the rainbow trout fillets by making the microstructure more compact. This process is accompanied by changes in texture and rheological properties, which next are running during the storage of a chilled or frozen product. These changes are significant enough for potential consumers to be made aware of the fact that the texture of the product changes considerably during its shelf life. Copyright © 2009 Society of Chemical Industry