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

Inactivation of palladium-based oxygen scavenger system by volatile sulphur compounds present in the headspace of packaged food

An oxygen scavenger based on a catalytic system with palladium (CSP) was recently developed to remove oxygen in food packagings. Although the CSP worked with various types of food, with some foods, an inhibition of the CSP was observed. Because such catalytic systems are susceptible to poisoning by sulfurcontaining compounds, the aim of this study was to understand the inactivation of palladium-based catalysts in presence of foods containing volatile sulfur compounds (VSCs). To achieve this, the oxygen scavenging activity (OSA) of the CSP was evaluated in presence of selected food products. Afterwards, VSCs mainly present in these foods were exposed to the CSP, and the influence on the OSA was evaluated. Finally, headspace analysis was performed with the diluted VSCs and with the packaged food products using proton transfer reaction time-of-flight mass spectrometry. It was found that the catalytic activity of the CSP was inhibited when VSCs were present in the headspace in concentrations ranging between 10.8–36.0 ppbv (dimethyl sulfide, DMS), 1.2–7.2 ppbv (dimethyl disulfide), 0.7–0.9 ppbv (dimethyl trisulfide), 2.1–5.8 ppbv methional) and 4.6–24.5 ppbv (furfuryl thiol). It was concluded that in packaged roast beef and cheese, DMS may be the compound mainly responsible for the inactivation of the CSP. In packagings containing ham, the key compounds were hydrogen sulfide and methanethiol; in peanuts, it was methanethiol; and in par-baked buns, an accumulation of methional, DMS, butanethiol and methionol. When potato chips were packaged, it was demonstrated that when VSCs are present in low concentrations, oxygen can still be scavenged at a reduced OSA

Rezension: Ahrenholz, Bernt (Hrsg.), Fachunterricht und Deutsch als Zweitsprache

Jeder Fachunterricht ist auch Sprachunterricht. Diese Erkenntnis ist weder überraschend noch neu, doch beginnt sie sich offenbar erst seit kurzem wirklich durchzusetzen – dank der Kinder und Jugendlichen mit Zuwanderungsgeschichte, die uns besonders dringlich vor Augen führen, dass die Inhalte aller Fächer sprachlich vermittelt werden. Wenn Kinder und Jugendliche mit Deutsch als Zweitsprache in der Regelschule lernen, bedeutet das, dass sie die Unterrichtsinhalte in einer Sprache verarbeiten (sollen), die sie zugleich noch lernen. Dass sie dies oft nicht erfolgreich tun können, haben verschiedene Studien gezeigt

Residual Stress Measurements Inside a Small Inner Diameter Hole at Low Bragg Angle Using X-Ray Diffraction Technique

Abstract. A new X-Ray diffraction (XRD) goniometer has been specially developed to nondestructively measure residual stress (RS) on the inner diameter (ID) of small holes in metal and ceramic components. The major advantage of this novel goniometer is its ability to perform RS measurements on the ID of small holes without the need to section the component, thus maintaining the integrity of the residual stress field inherent to the component of interest. This new patented XRD goniometer has been used on a wide variety of aerospace components on features such as holes in airframe/structural components, as well as fastener/bolt holes, air holes, and confined areas on rotating and non-rotating turbine engine components. In many instances, measurements can be performed at 2θ angles much lower than the widely accepted lower limit of approximately 130°. The selection of the actual Bragg angle used depends upon the material itself, the hole ID, and the thickness of the component. Results obtained indicate that the new goniometer can be used to measure RS on the ID of small holes with good accuracy and precision even at relatively low 2θ angles in the vicinity of 100°