Fast Automated Determination of Total Tocopherol Content in Virgin Olive Oil Using a Single Multicommuted Luminescent Flow Method

Tocopherols are natural fluorophores of great importance for the characterization and authentication of virgin olive oil. Herein, a single automatic multicommuted flow method has been developed for the determination of total tocopherol content as well as the semi-quantitative estimation of α-tocopherol in extra virgin olive oil (EVOO) samples. Only appropriate dilution of samples with 2-propanol was necessary for their direct analysis by a multicommuted flow injection (MCFIA) manifold based on three solenoid valves with fluorescence detection. The peak height at λ _em = 330 nm (emission) with λ _exc at 296 nm was used as analytical signal. Linear response was observed within the range from 50 to 350 mg of tocopherols (expressed as α-tocopherol kg^?1 olive oil), suitable to cover the usual range for tocopherols in (extra) virgin olive oil ((E)VOO)). The results were consistent with those obtained by reversed-phase HPLC reference method, whereas the analysis time was significantly reduced. The sample frequency of the proposed automatic method was close to 40 samples h^?1, in contrast to typically 15–30 min required by HPLC. The method is fast, straightforward, cost-effective, and easy to implement in routine laboratories for screening purposes.     

Characterisation of Micrococcaceae isolated from different varieties of chorizo

A total of 426 strains of Micrococcaceae bacteria isolated from chorizo (a traditional Spanish fermented sausage) were identified. The chorizos were sampled from three regions of Castilla and León in Spain: Burgos, Segovia and Salamanca. Two factories were chosen in each region and the samples were taken at three stages of ripening. Staphylococcus xylosus was the most predominant species isolated (95%). Twelve strain types of S. xylosus were established according to their fermentation patterns, and two of them, S. xylosus type 2 and S. xylosus type 5, made up the majority of the strains of S. xylosus isolated (27 and 52%). Production of acetoin, nitrate reductase, urease activity, proteolytic and lipolytic activity were determined for all isolates. The percentage of strains of S. xylosus producing acetoin depends on the manufacturing location. In general, the proteolytic and lipolytic activities of the S. xylosus isolated from chorizo from Castilla and León were low and moderate; 97% of the strains showed nitrate reductase and urease activity. According to our results and to previous investigations, it seems that S. xylosus type 5, showing nitrate reductase and urease activity, low-moderate proteolytic and lipolytic activities and not producing acetoin would be suitable as a starter culture. Of the strains isolated in this study, 38% comply with these requirements.     

TaqMan real-time PCR for the detection and quantitation of pork in meat mixtures

A rapid and highly specific real-time quantitative PCR, based on the amplification of a fragment of the mitochondrial 12S ribosomal RNA gene (rRNA), has been developed for the quantitation of pork (Sus scrofa) in binary pork/beef muscle mixtures. The method combines the use of pork-specific primers, that amplify a 411bp fragment from pork DNA, and mammalian-specific primers amplifying a 425-428bp fragment from mammalian species DNA, which are used as endogenous control. An internal fluorogenic probe (TaqMan), that hybridizes in the "pork-specific" and also in the "mammalian" DNA fragments is used to monitor the amplification of the target gene. A comparison of the cycle number (C(t)) at which mammalian and pork-specific PCR products are first detected, in combination with the use of reference standards of known pork content, allows the determination of the percentage of pork in a mixed sample. Analysis of experimental pork/beef muscle binary mixtures demonstrated the specificity and sensitivity of the assay for detection and quantitation of pork in the range 0.5-5%.     

Polycyclic aromatic hydrocarbons (PAHs) in two Spanish traditional smoked sausage varieties: "Chorizo gallego" and "Chorizo de cebolla"

The polycyclic aromatic hydrocarbon (PAH) content in two traditional smoked sausages from Spain was determined. Results showed, that total average levels of PAHs found were higher in "Chorizo de cebolla" (101.81 vs. 98.48 μgkg(-1)). Most contents of PAHs found in both sausages were phenanthrene, naphthalene and anthracene. The maximum level for benzo[a]pyrene (BaP) of 5 μgkg(-1) in smoked meat products was not exceeded in any samples. BaP represented a 0.73% and 1.15% with respect to the total sum of the 15 PAHs that were investigated in this study for "Chorizo gallego" and "Chorizo de cebolla", respectively. Correlation statistic analysis (P < 0.01) of the contents from samples analysed, showed that BaP was a good marker for Σ15 PAHs in "Chorizo gallego" samples (R(BaP/Σ15PAHs) = 0.77; P < 0.01) and it was a good marker for 7 U.S. EPA probably carcinogenic PAHs in "Chorizo de cebolla" samples (R(BaP/7EPA) = 0.95) and in "Chorizo gallego" samples (R(BaP/7EPA) = 0.81).     

Effect of environmental daily temperature fluctuations over one year storage on the prediction of non-enzymatic browning in reduced-moisture foods stored at “ambient” temperature

Non-enzymatic browning predictions in reduced-moisture foods stored over one year at “ambient” temperature, were made using, (a) realistic environmental daily (and seasonal) temperature fluctuations, and (b) a constant mean temperature. Daily temperature records taken every 6 h from January 1st to December 31st (1460 temperature data) in four selected cities from Argentina, were used.

The predicted amount of browning over one year storage was different depending whether the annual mean temperature (T_am), the monthly mean temperature (T_mm) or the daily temperature fluctuations (T_df) were used for the predictions. Predicted browning over one year was generally higher when realistic storage conditions (i.e., daily/seasonal temperature fluctuations) rather than mean values (annual or monthly), were used instead.     

Context awareness in network selection for dynamic environments

Mobile devices of new generation are able to connect to multiple networks and to constitute new infrastructureless networks. These dynamic environments require new security paradigms and automatic mechanisms to minimize user intervention. Our goal is the definition of a new concept of distance that considers the current domain constraints and the user preferences. This paper addresses some of the problems of these complex environments by using Multidimensional Scaling (MDS) techniques. We also propose collaborative mechanisms for automatic environment marking. Based on these ideas we have developed Pervasive Interaction Manager (PervsIM), a decision mechanism that selects the most appropriate network or peer to interact with. Besides we have defined an embedded access control module which ensures that PervsIM decisions are followed by all applications. Furthermore, several simulation results and implementation details outline how these results can be incorporated in today’s mobile devices.     

B-lymphoproliferative disorders in patients with hepatitis C virus infection

Blastomycosis is an endemic systemic fungal infection that usually involves the lungs and superficial skin. Although head and neck involvement has been reported in the literature, no previous cases of neck mass resulting from direct extension of a pulmonary lesion have been published. We encountered an immunocompetent 31-year-old woman with a rapidly enlarging subcutaneous neck mass and a chronic upper lung infiltrate. Imaging studies showed contiguity between both lesions. Blastomyces dermatitidis was recovered from the sputum, and typical yeast was observed in fungal stains of needle aspirate from the neck mass. The patient responded favorably to a 6-month course of itraconazole. Blastomycosis should be considered in patients with subcutaneous neck masses in areas where this disease is endemic.     

Response of two populations of holm oak (Quercus rotundifolia Lam.) to sulfur dioxide

Experiments were carried out with seedlings of Quercus rotundifolia Lam., an evergreen schlerophyllous tree typical of the Spanish Mediterranean climate environments. Fruits were collected in two distant (800 km) populations located in the center (southern Spain) and northern border (northern Spain) of the area of distribution of the species. One-month-old potted plants were grown for 130 days in an enriched atmosphere of SO2 (0.23 ppm, 14 h/day) in controlled (growth chamber) conditions. Both northern and southern plants underwent a significant decrease in growth rate as a consequence of the treatment. Even so, plants appear to be quite resistant to SO2 compared with either more temperate or more productive species. The southern population was more sensitive to the treatment, as reflected by the bigger decrease in both growth and photosynthetic rates. Differences in resistance appear to be related to the biogeographic origin of the populations studied, which underlines the importance of biogeographic aspects in studies of resistance to air pollutants.