Traps sensory

Other methods explored internally to alter the form of nicotine delivered included the use of base- or acid-coated filters. For example, researchers at RJR applied sodium hydroxide-coated filters to a cigarette yielding only 0.06 mg of nicotine in order to heighten sensory impact (Shannon et al. 1992). Alternately, a filter coated with an acid (lactic, levulinic, citric) was used to reduce the impact of a high nicotine sheet, either by trapping the nicotine or by changing the pH of the smoke so there is not as much lucotine in the vapor phase (Shannon et al. 1992). The researchers noted that ... 

Olfactoiy thresholds also vary with the ovarian cycle. Women are most sensitive to odors around the time of ovulation, when estrogen levels are highest, and less sensitive to odors during menstruation. This may have sensory-physiological reasons. During menstruation the mucus layer on the olfactory epithelium is thicker and more likely to trap molecules, while the thin mucus layer at the time of ovulation renders the receptors more accessible. The thickness of the mucus layer, in turn, is controlled by testosterone and estrogen (Mair etal, 1978). 

Describes a simple and sensitive spectrophotometric method to estimate the content of total carbonyl compounds in rancid fats and foods by trapping them with 2,4-DNPH the technique determines total carbonyls, including those that are nonvolatile, decreasing the ability of the assay to correlate well with sensory data. Although gas chromatographic techniques are better suited for determining volatile carbonyl compounds from lipid oxidation, this is still the classical colorimetric assay. 

Sensory Validation of Sampling and GC Techniques. The sensory evaluation was carried out by a panel of three judges (employees of Pebeyre Ltd.). For this study, an external odor port was attached to the gas vent of the D.C.I. system. After the thermal desorption of the volatiles from the trap, the rotary valve was positioned so that the unresolved aroma isolate went to our sniffing port. The response was mesured as similarity or dissimilarity to canned black truffle aroma. 

Under our optimized sampling conditions, no blocking of the trap (visually verified at the manometer of the scavenging gas circuit) and no losses of volatiles during the adsorption phase (sensorially verified at the odor port) were observed. 

Durst, G., Laperle, E. 1990. Styrene monomer migration as monitored by purge and trap gas chromatography and sensory analysis for polystyrene containers. J. Fd. Science. 55 522-524. 

The volatile compounds in the atmosphere of cold stored Black Perigord Truffles (Tuber Melanosporum) were adsorbed onto a Tenax trap by means of a vacuum pump. The efficiency of the sampling method was sensorially validated. The volatiles eluted from the trap by heat desorption were analysed by capillary gas chromatography - mass spectrometry. A total of 26 compounds was identified. Their contribution to the final aroma impression was discussed. 

Finally, an improvement in the sensitivity of the detection limit for such compounds can be reached by using a Purge and Trap well-optimized enrichment approach instead of the HS-SPME technique (Fedrizzi et al., 2007b). This method provides enough sensitivity, and analysis times are suitable to perform routine analysis. The measured amounts are, in fact, within the variability ranges reported in the literature for both compounds in wine, and close to the sensory thresholds. Using both such methods, it has been possible for the first time to measure the contents and relevant ratios of such compounds in Italian wines of different varieties as represented in Figure 5.10. 

Beside the most commonly used ion separation systems, such as the quadrupole mass analyser, the ion-trap mass analyser and the double-focusing and tri-sector mass analyser, a new system has encountered increasing interest. This system, the time-of-flight (TOP) mass analyser offers fast scanning opportunities coupled with the possibility of detecting ions with high m/z ratios. This provides a useful tool for rapid quality control of sensorial profiles as well as the detection and identification of toxins and proteins or protein-bound substances [42]. 

Fig. 16.1 Visual deception in crustaceans. Bluffing RHP wherein the size of the weapon may not reliably indicate strength (a) Alpheus heterochaelis (b) Uca perplexa (c) Cherax dispar. Hiding burrow entrance and self (d) female Uca beebei and her chimney. Sensory traps based on responses selected by predation (e) Uca terpsichores male and his hood (f) U. terpsichores male running over his hood and startling a female into his burrow (Image credits (a) Melissa Hughes (b, d, and e) John Christy (c) Anthony O Toole courtesy of Robbie Wilson (f) drawn by Donna Conlon)...

Christy JH (1995) Mimicry, mate choice and the sensory trap hypothesis. Am Nat 146 171-181 Christy JH (1997) Deception the correct path to enlightenment Trends Ecol Evol 12 160 Christy JH (2007) Predation and the reproductive behavior of fiddler crabs (genus Uca). In Thiel... 

Macias-Garcia C, Ramirez E (2005) Evidence that sensory traps can evolve into honest signals. Nature 434 501-505... 

---