Volatile Profile Characterization of Extra Virgin Olive Oils from Argentina by HS-SPME/GC-MS and Multivariate Pattern Recognition Tools

The distinctive aroma of virgin olive oil is attributed to a large number of chemical compounds of different classes such as aldehydes, alcohols, esters, hydrocarbons, ketones, furans, and other volatile compounds that are not yet identified. The aim of the present study lies in the characterization of compound volatile profile of the most representative olive oil cultivars produced in Argentina. The methodology proposed was based on the development of headspace (HS)-SPME/GC-MS with the subsequent analysis of the chemical fingerprints using a discriminant analysis method and a principal component analysis data compression strategy to distinguish olive oils from different varietal origins. Carboxen/polydimethylsiloxane (75 μm) fiber was the most efficient to trap volatile compounds. Optimization of the SPME conditions was also carried out using multivariate methods. To avoid the influence of factors other than the cultivar, olive trees were cultivated under the same agronomic and pedoclimatic conditions; olive fruits were picked at the same stage of ripeness, and their oils were extracted with the same processing system. Volatile fractions from oils of the analyzed cultivars consisted of a complex mixture of more than 40 compounds. Both quantitative and qualitative differences were found among cultivars. The analytical data association with multivariate analysis constitutes a reliable analytical tool with potential ability to discriminate monovarietal extra virgin olive oil from Argentina.     

Gustatory Responsiveness to Six Bitter Tastants in Three Species of Nonhuman Primates

Gustatory responsiveness of six adult squirrel monkeys, four spider monkeys, and five pigtail macaques to six bitter tastants was assessed in two-bottle preference tests of brief duration (2 min). Animals were given the choice between a 30-mM sucrose solution and defined concentrations of a bitter tastant dissolved in a 30-mM sucrose solution. With this procedure, Saimiri sciureus, Ateles geoffroyi, and Macaca nemestrina were found to significantly discriminate concentrations as low as 0.2, 0.05, and 0.1 mM quinine hydrochloride; 1, 1, and 0.05 mM caffeine; 20, 5, and 1 mM naringin; 5, 2, and 1 mM salicin; 0.01, 0.001, and 0.02 mM sucrose octaacetate; and 0.05, 0.01, and 0.5 mM denatonium benzoate, from the alternative stimulus. With the exception of naringin in the pigtail macaques, all three species rejected all suprathreshold concentrations of all bitter tastants tested. The spider monkeys and the pigtail macaques displayed the lowest taste avoidance thresholds with three of the six tastants each; in contrast, the squirrel monkeys displayed the highest taste avoidance thresholds with four of the six tastants. The across-tastant patterns of taste avoidance thresholds were identical in spider monkeys and squirrel monkeys; both species displayed the following order of sensitivity: sucrose octaacetate > denatonium benzoate > quinine hydrochloride > caffeine > salicin > naringin. All three primate species were more sensitive to the two artificial tastants (sucrose octaacetate and denatonium benzoate) compared to the four naturally occurring tastants. However, the concentrations detected by all three primate species with the four naturally occurring tastants are well below those reported in plants or arthropods consumed by these species suggesting that they may use bitterness as a criterion for food selection.     

Fetal Bovine Serum Concentration Affects Δ<Superscript>9</Superscript> Desaturase Activity of <Emphasis Type="Italic">Trypanosoma cruzi</Emphasis>

Fetal bovine serum (FBS) is an important factor in the culture of Trypanosoma cruzi, since this parasite obtains and metabolizes fatty acids (FAs) from the culture medium, and changes in FBS concentration reduce the degree of unsaturation of FAs in phosphoinositides. When T. cruzi epimastigotes were cultured with 5% instead of 10% FBS, and stearic acid was used as the substrate, ∆⁹ desaturase activity decreased by 50%. Apparent K _m and V _m values for stearic acid, determined from Lineaweaver–Burk plots, were 2 μM and 219 pmol/min/mg of protein, respectively. In studies of the requirement for reduced pyridine nucleotide, ∆⁹ desaturase activity reached a maximum with 8 μM NADH and then remained constant; the apparent K _m and V _m were 4.3 μM and 46.8 pmol/min/mg of protein, respectively. The effect of FBS was observed only for ∆⁹ desaturase activity; ∆¹² desaturase activity was not affected. The results suggest that decreased FBS in culture medium is a signal that modulates ∆⁹ desaturase activity in T. cruzi epimastigotes.     

Folate and iron in fertile age women from a Venezuelan community affected by incidence of neural tube defects

The objective of this transversal study was to determine folate and iron nutritional status of women in fertile age from Municipio Jiménez, Lara State, Venezuela. The sampling was probabilistic by conglomerates from the urban and rural areas, selecting 15 conglomerates from which women between 12 and 45 years (269), were studied. After signing informed consent, participating were interviewed for personal data, antecedents related to folate and iron, socioeconomic data (Graffar-Mendez Castellano method and unsatisfied basic needs). In blood sample was determined Hemoglobin, and Erythrocytic Folate (FE). Serum was obtained to determine Ferritin and Serum Folate (FS). 53.53% of the sample presented low FS levels, 10.78% were FS deficient. Severe FE deficiency was present in 80.7% of the cases, moderate deficiency affected 5.9%. For both tests, median was higher for women in treatment with Acido Fólico or pregnant (p = 0.000), median for FE was higher for adults (p = 0.001) and in non poor women (p = 0.011). There were no significant differences for coffee, alcohol, anticonceptive consumption, urban or rural resident or socioeconomic strata. The prevalence of anemia was 11.2% being significantly more frequent in adults than in adolescents (p = 0.029) and in urban women (p = 0.042). Low ferritin were found in 37.3% of the sample, the effect of different variables was not statistically significant. In conclusion, there is a high prevalence of iron and folate deficiencies in women of fertile age from Municipio Jiménez, which could constitute a conditioning factor for the appearance of neural tube defects.     

Deposition and characterization of MgO/Si gate stacks grown by molecular beam epitaxy

In this article, the deposition and characterization of amorphous MgO films grown on Si (001) using molecular beam epitaxy is reported. In order to ensure amorphous films, low substrate temperatures (200 °C) and high oxygen pressures were used (up to 5 × 10^− 3 Pa). Both atomic and molecular oxygen species were used at different pressures. Films ranging in thickness from 3 nm till 30 nm were grown and characterized using structural and electrical methods.The dielectric constant deduced from this thickness series corresponds to 8.74 close to the bulk value of 9.8. The best equivalent oxide thickness value observed for this series - grown under high oxygen pressure - corresponds to 1.2 nm for a current density measured at V_FB − 1 V of 0.1 A/cm². The films grown with atomic oxygen display a lower capacitance and lower leakage compared to the films grown using molecular oxygen. This is due to the appearance of a thin SiO₂ interface layer which is also responsible for the high defect density observed in the capacitance-voltage measurements. Upon annealing both types of films in forming gas for 15 min at 450 °C, the capacitance decreases further while the leakage increases. This change is assigned to the appearance of the lower bandgap (6.6 eV), lower dielectric constant (6.6) phase of silicate, MgSiO₃. Furthermore a V_FB shift of − 0.6 V is observed and is related to the appearance of oxygen vacancies as Mg diffuses into the SiO₂ interface layer.     

A SCADA oriented middleware for RFID technology

Radio Frequency IDentification (RFID) has emerged as the new technology paradigm for acquisition and information management. RFID can be used to improve significantly the efficiency of business processes by providing the capability of automatic identification and data capture. This technology introduces new challenges on data and process information management in current systems. RFID data are time-dependent and dynamically changing. In addition, data carry implicit semantics. The homogeneous data processing of such implicit semantics allows us to propose RFID middleware as a WHO–WHEN–WHERE data problem. This paper presents DEPCAS, a new middleware for RFID information based on the SCADA architecture for control systems. An application of DEPCAS is the resolution of heterogeneous situations, which solves the WHAT or context-aware to apply the auto identification data received from RFID systems in business applications.     

Effect of damaged starch on the rheological properties of wheat starch suspensions

The influence of damaged starch content on particle size distribution and rheological properties of unheated starch suspensions and pasting properties were investigated. Four samples containing different amounts of damaged starch were studied. Particle size distribution curves shifted toward higher diameters, and a greater overlap of both populations of particles (A- and B-type granules) and a decrease of both peak heights were produced. The flow curves of unheated starch suspensions were fitted using the power law model. The flow behavior indexes were higher than the unit. The consistency coefficient increased with the increment of damaged starch content. Unheated starch suspensions showed time-dependent rheological behavior and were described by the Weltman model. The unheated suspensions exhibited a thixotropic behavior. With regard to the pasting process, the increment of damaged starch content produced gradual reductions in peak viscosity, final paste viscosity, breakdown and setback. Results demonstrated the importance of the presence of physically damaged granules in wheat starch rheological characteristics.     

The role of lipid oxidation on biscuit texture during storage

The role of lipid oxidation and humidity absorption on the shelf life of biscuits was analysed. Biscuits with low lipid and sugar content were prepared employing different oils, and texture changes that biscuits experience during storage were studied. Water activity, peroxide value, malonaldehyde content and colour were also determined at different storage times. The maximum peroxide level was between 1 and 1.5 mmol kg^?1 of oil, at 166 days of storage. Values of malonaldehyde were between 5.2 and 15.8 nmol g^?1 of dry sample. Water activity and peroxide value influence the biscuit texture (P ≤ 0.05). To study the effects of both factors simultaneously, a mathematical model was adjusted to the data. Results indicate that an increase in the peroxide level, even at low level of lipid oxidation, increases Young's modulus and leads to a harder biscuit, while the humidity absorption lowers the fracture stress and Young's modulus.