Structural, magnetic, dielectric and mechanical properties of (Ba,Sr)MnO3_3 ceramics

Ceramic samples, produced by conventional sintering method in ambient air, 6H-SrMnO$_3$(6H-SMO), 15R-BaMnO$_3$(15R-BMO), 4H-Ba$_{0.5}$Sr$_{0.5}$MnO$_3$(4H-BSMO) were studied. In the XRD measurements for SMO the new anomalies of the lattice parameters at 600-800 K range and the increasing of thermal expansion coefficients with a clear maximum in a vicinity at 670 K were detected. The N$\acute{e}$el phase transition for BSMO was observed at $T_N$=250 K in magnetic measurements and its trace was detected in dielectric, FTIR, DSC, and DMA experiments. The enthalpy and entropy changes of the phase transition for BSMO at $T_N$ were determined as 17.5 J/mol and 70 mJ/K mol, respectively. The activation energy values and relaxation times characteristic for relaxation processes were determined from the Arrhenius law. Results of ab initio simulations showed that the contribution of the exchange correlation energy to the total energy is about 30%.Comment: 12 pages, 12 figure

The effect of Camelina sativa cake diet supplementation on sensory and volatile profiles of ewe’s milk

The aim of this study was to evaluate the sensory profile based on the principal component analysis (PCA) and cluster analysis of Euclidean distances as well as evaluate a volatile profile in ewes’ milk. The analysis was conducted using SPME GC/TOFMS. Tested milk came from ewes fed concentrate supplemented with 10 and 20% Camelina sativa (L.) Crantz cake (CSC). This plant containing unsaturated fatty acids as well as natural antioxidants (for example, tocopherol), may constitute an excellent source of energy in the feed ratio for animals, at the same time improving the composition of fatty acids in milk fats. Milk of ewes fed CSC had a distinct animal, grainy and processed aroma. After pasteurization, the cooked and dairy fat aroma intensified. At the same time the overall dairy aroma, highly characteristic of the control milk, was considerably reduced. An addition of CSC to the diet of ewes resulted in an increase in the content of volatiles, primarily fatty acids. The applied milk pasteurization had a significant effect on a further increase in the contents of volatiles. First of all furans, furanones and furfural, being the Maillard reaction products, were accumulated.Key words: Sheep milk, sensory analysis, flavor analysis, volatiles in milk

Characterization of aroma compounds in Portuguese extra virgin olive oils from Galega vulgar and Cobrançosa cultivars using GC-O and GC-x-GC-ToFMS

Aroma compounds of virgin olive oils extracted from two olive cultivars – Galega Vulgar and Cobrançosa – grown in Beira Baixa region in central Portugalwere investigated. Gas chromatography–olfactometry (GC–O) was carried out to select the important odorants for subsequent comprehensive gas chromatography/time of flightmass spectrometry (GC × GC–ToFMS) analysis. By GC–O fifteen odorants were identified. For the quantification of volatile compounds, headspace solid phasemicroextraction (SPME) techniquewas optimized. Under optimized conditions, 22 volatile compounds were quantified in all samples. Trans-2-hexenal was the most abundant compound. A discriminant analysis (DA) was used to discriminate among olive oil samples obtained from olives of the two cultivars with different harvest time/ripening stages. Concerning the harvesting time and cultivar, nine volatiles showed to have discriminant power among samples, namely heptanal, trans-2-hexenal, 1-octen-1-ol, nonanal, 2,3-butanedione, ethyl-2-methylbutyrate, hexanal, cis-3-hexenylacetate and 3-methylbuthylacetat

Quantum interface of an electron and a nuclear ensemble.

Coherent excitation of an ensemble of quantum objects underpins quantum many-body phenomena and offers the opportunity to realize a memory that stores quantum information. Thus far, a deterministic and coherent interface between a spin qubit and such an ensemble has remained elusive. In this study, we first used an electron to cool the mesoscopic nuclear spin ensemble of a semiconductor quantum dot to the nuclear sideband-resolved regime. We then implemented an all-optical approach to access individual quantized electronic-nuclear spin transitions. Lastly, we performed coherent optical rotations of a single collective nuclear spin excitation-a spin wave. These results constitute the building blocks of a dedicated local memory per quantum-dot spin qubit and promise a solid-state platform for quantum-state engineering of isolated many-body systems

Effect of triticale grain characteristics, scouring, and extrusion conditions on physico-chemical properties, antioxidant activity, and volatile compounds of flat bread

The objective of the study was to determine the effect of grain preparation technology, extrusion cooking conditions, and triticale cultivars on physico-chemical properties of crisp bread. Triticale cultivars used in the experiments differed in protein content, starch content, amylolytic activity, and viscosimetric properties. The type of the twinscrew extruder used has an effect on starch degradation, phenolic contents, and antioxidant activity of the product, but a greater effect on those characteristics is found for grain scouring prior to extrusion. All factors had an effect on volatile compound amounts in crisp bread, but the direction and range of these changes were random in character. Results of this study show that triticale grain can be useful raw material for the production of flat bread

Changes in aroma and sensory profile of food ingredients smoked in the presence of a zeolite filter

During smoking, formation of desirable smoky compounds and carcinogenic polycyclic aromatic hydrocarbons (PAH) are inextricably linked. We have previously developed a zeolite filter technology (PureSmoke Technology or PST) that reduces the PAH content of a smoke stream, particularly reducing the concentration of benzo[a]pyrene, a known carcinogen, by up to 93%. The aim of this work was to determine whether there were changes in the volatile and sensory profiles of ingredients smoked using PST compared to the traditional smoking process (Trad). Smoked tomato flakes (either PST or Trad) were added to either low-fat or full-fat cream cheese for sensory profiling and consumer preference tests, and volatile analysis was carried out using solid phase microextraction (SPME) followed by gas chromatography-mass spectrometry (GC-MS). The sensory analysis showed a significant decrease (p < 0.01) in bitterness when the PST was employed and a significant decrease in overall smoky aroma and flavor (p < 0.001), which resulted in an increase in the perception of cheesy aroma and flavor. This was consistent with a decrease in many of the smoky aroma compounds, particularly the guaiacols. However, consumer preference tests showed that there was no adverse effect on the flavor of the products, and there was even a tendency for the PST product to be preferred to the Trad product (p = 0.096). The smoke compounds were quantitated and compared in smoked tomato paste. Odor activity values (OAVs) calculated from the literature thresholds suggested that guaiacol and 4-alk(en)yl-substituted guaiacols are likely to be among the most highly odor-active compounds in these smoked ingredients