Novel Mass Spectrometry Methods in Flavour Analysis

Flavour research is a demanding domain in terms of analytical methodology as key odorants usually occur in trace amounts, often embedded in extracts containing volatile compounds at much higher concentrations. Since its early days, GC-MS has been a key tool in flavour laboratories enabling characterisation of thousands of volatile components in food products. However, as flavour chemists delve deeper into the understanding of flavour generation and delivery, there is a need for more powerful methodologies adapted to their specific needs. This paper will present two techniques that allow flavour separation and characterisation, namely GC-TOFMS and MS/MS. Moreover, APCI-MS, PTR-MS and REMPI-TOFMS will be discussed as they enable direct investigation of volatile compounds without any chromatographic step, thus studying release of flavour compounds during food processing or food consumption

Olfaction, where nutrition, memory and immunity intersect

The development of mechanisms that simultaneously protect and nourish an organism within a particular environment is key to survival, and these mechanisms represent an important Darwinian selective pressure. The ability of organisms to learn from their surroundings and to improve their biochemical responses to that environment is becoming increasingly well established as forms of imprinting and metabolic memory. Within this context, the development of olfactory preferences is a vivid example of acquired memories. Food is not only a source of nutrients, but also the chemicals that elicit characteristic volatile aromas and lead to preferences for particular food choices. Ideally, the memories formed in response to exposures to diets enhance an individual’s ability to succeed in a particular environment, including the available foods. However, the failure of modern diets to deliver increasing health to the entire population is testament to the inability of all humans to match food choices to optimal nutritional requirements in all environments and lifestyles. The ability to reformulate food commodities and foods with widely varying nutritional and flavour properties has the potential to both confound and enhance the processes of flavour preference and food choice. Enhancing food choices based on flavour preferences will require an understanding of precisely how flavour preferences are developed. The tools to simultaneously measure aroma exposure, aroma perception and metabolic responses to foods are at hand. Bringing these tools to practice and joining the fields of flavour science, nutrition and metabolic assessment into a new era of personalised diet and health is an attractive possibility

Partial separation of fullerenes by gradient sublimation

An experimental technique is investigated to separate/enrich fullerenes or metallofullerenes, exploiting differences in sublimation temperatures without the use of solvents. Fullerenes are sublimed out of the soot and deposited on a quartz rod along a temperature gradient (gradient sublimation). In a position-sensitive experiment the composition of the deposit on the rod is monitored by laser-desorption mass spectrometry. Strongly enriched regions containing specific fullerene molecules (i.e., C84 or La@ C82) are observed. Furthermore, C74, which could not be extracted from the soot by organic solvents, sublimes out of the soot

Global multi-hazard risk assessment in a changing climate

Natural hazards pose significant risks to people and assets in many regions of the world. Quantifying associated risks is crucial for many applications such as adaptation option appraisal and insurance pricing. However, traditional risk assessment approaches have focused on the impacts of single hazards, ignoring the effects of multi-hazard risks and potentially leading to underestimations or overestimations of risks. In this work, we present a framework for modelling multi-hazard risks globally in a consistent way, considering hazards, exposures, vulnerabilities, and assumptions on recovery. We illustrate the approach using river floods and tropical cyclones impacting people and physical assets on a global scale in a changing climate. To ensure physical consistency, we combine single hazard models that were driven by the same climate model realizations. Our results show that incorporating common physical drivers and recovery considerably alters the multi-hazard risk. We finally demonstrate how our framework can accommodate more than two hazards and integrate diverse assumptions about recovery processes based on a national case study. This framework is implemented in the open-source climate risk assessment platform CLIMADA and can be applied to various hazards and exposures, providing a more comprehensive approach to risk management than conventional methods.ISSN:2045-232

Endohedral rare-earth fullerene complexes

The technique or carbon-arc evaporation has been successfully utilized to encapsulate a wide variet y of rare-earth species in carbon cases. We have observed Mm@Cn (M = Ce, Nd, Sm. Eu, Gd, Tb, Dy, Ho or Er } species present in the toluene extracts of the carbon soot using laser desorption mass spectrometry. The presence of multiple-metal species appears to depend strongly on the metal-to-carbon atom ratio found in the starting rods, with the higher metal concentrations favouring multiple-metal incorporation. One often observed dimetallcfullerene is M2@C80. Molecular orbital arguments are presented to support a possible icosahedral structure for C80

Degradation of coffee flavor compound furfuryl mercaptan in fenton-type model systems

The stability of the coffee flavor compound furfuryl mercaptan has been investigated in aqueous solutions under Fenton-type reaction conditions. The impact of hydrogen peroxide, iron, ascorbic acid, and ethylenediaminetetraacetic acid was studied in various combinations of reagents and temperature. Furfuryl mercaptan reacts readily under Fenton-type reaction conditions, leading to up to 90% degradation within 1 h at 37°C. The losses were lower when one or more of the reagents was omitted or the temperature decreased to 22°C. Volatile reaction products identified were mainly dimers of furfuryl mercaptan, difurfuryl disulfide being the major compound. In addition, a large number of nonvolatile compounds was observed with molecular masses in the range of 92-510 Da. The formation of hydroxyl and carbon-centered radicals was indicated by electron paramagnetic resonance spectra using alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone or 5-(diethoxyphosphoryl)-5-methyl-1-pyrroline-N-oxide as spin traps. Whereas *OH was generated by Fenton-type reactions, the C-centered radical is probably a secondary product of the reaction of *OH with various organic molecules, the reaction with furfuryl mercaptan appearing to be the most important. No evidence for S-centered radicals was seen in the spin-trapping experiments, but a sulfur-containing radical was detected when measurements were made at 77 K in the absence of spin traps