Evaluation of the influence of mastication on temporal aroma release of ripe and unripe bananas,using a model mouth system and gas chromatography-olfactometry

The effect of the mastication rate on temporal aroma release from ripe and unripe bananas was investigated using a model mouth system and analysing the volatiles by gas chromatography-olfactometry (GC-O) and gas chromatography-mass spectrometry. Large differences were found in the numbers of odour active compounds of ripe and unripe bananas as well as for the three different mastication rates investigated (0, 26 and 52 min^-1). Hexanal was the only compound that was detected by all six assessors for ripe and unripe bananas for each mastication speed. In the odour profile of ripe and unripe bananas with a mastication rate of 52 min^-1, 18 and 7 significant odour active compounds respectively were detected whereas with a mastication rate of 26 min^-1, 15 and 3 respectively were detected. Without mastication only 3 and 2 compounds respectively were observed. Principal component analysis on GC-O data allowed an easy separation between the three chewing speeds and the ripe and unripe bananas.     

Changes in flavour release from rehydrated: Diced bell peppers (Capsicum annuum) by artificial saliva components in three mouth model systems

The effect of artificial saliva components on flavour release from dehydrated diced red bell peppers (Capsicum annuum) was studied in a mouth model system. This measured the dynamic headspace under oral conditions, such as temperature, volume of the mouth, salivation, and mastication (DHM). The results were compared with a dynamic headspace (DH) and a purge-and-trap (PT) model system. Volatile compounds were analysed by gas chromatography, using flame ionisation detection (FID), mass spectrometry (MS), and sniffing port detection (SPD). SPD revealed that only 12 of the 47 compounds identified by MS and FID possessed odour activity. For all saliva compositions FID peak areas of volatile compounds were largest in the PT system, followed by DHM and DH, respectively. In the PT system the less volatile compounds were relatively better released than other volatile compounds in comparison with the DHM and DH system, for all salivas. The saliva components mucin and α-amylase caused a relative decrease in release of the less volatile compounds in all model systems. An overall decrease in FID peak areas of volatile compounds by the latter components was observed in model system DH only.     

Creating chiral centres in zeolite Y by the introduction of R-1,3-dithiane 1-oxide as a modifier: Computer simulation of the modifier stability

In an earlier paper we have shown that R-1,3-dithiane 1-oxide adsorbed in zeolite Y is able to dehydrate the S enantiomer of butan-2-ol at a rate of up to 19 times greater than the R enantioner. Thus a heterogeneous enantioselective catalyst has been produced by the introduction of a chiral modifier into an achiral zeolite. The modifier remains stable at temperatures of up to at least 180°C. In this paper we present results of computer simulation work on this system which suggest that the observed stability of the R-1,3-dithiane 1-oxide in the zeolite is due to proton transfer between the zeolite and the molecule. We suggest that the molecule is present as a counter cation to the framework. A combination of energy minimisation, Monte Carlo and molecular dynamics techniques are used to study the zeolite Y and R-1,3-dithiane 1-oxide system. Consistent force field potentials are used to describe both the zeolite framework and the adsorbed molecule.     

Neuroethik – Geschichte,Definition und Gegenstandsbereich eines neuen Wissenschaftsgebiets

Definition of the problem

Fifteen years after establishing neuroethics as an international academic field, neuroethics has emerged as a vibrant, dynamic area of scientific research.

Arguments

Within a short period of a few years, specific conferences, journals, research funding programs, professional societies, and institutes were founded. Nonetheless, considerable disagreement about its definition and subject matter still remain. We argue for a differentiated conceptualization according to which the deliberate reflection of ethical problems arising from the neurosciences and their predominantly neurotechnological application belongs as much to neuroethics as does the ethical reflection of the neuroscience of morality. This does not comprise neuroscientific or neuropsychological research on morality itself, but includes the contemplation of the significance of such research for ethics and the law. Here, we provide an overview about the most important topics in neuroethics and elucidate the relevance of neuroethics for a vast diversity of societal domains reaching well beyond medicine and health care.

Conclusion

The great potential of neuroethics as a novel branch of academic research lies in finding new answers to pressing questions of high societal relevance by linking neurophilosophy and bioethics topics as well as its broad interdisciplinary network.

     

A Fast Quantitative Multi-analyte Method for Growth Promoters in Bovine Meat Using Bead-Disruption, 96-well SPE Clean-up and Narrow-Bore UHPLC-MS/MS Analysis

A new method for detecting low levels of growth promoters in bovine meat was developed with the following goal: easy, fast and sensitive analysis of a wide range of compounds, with reduced consumption of chemicals and disposables. Several classes of growth promoters were included, i.e. resorcylic acid lactones (RALs) and steroids, the latter including corticosteroids and gestagens. For sample treatment, 0.5 g of homogenised bovine meat was simultaneously disrupted and extracted in a bead-ruptor machine. The organic extraction solvent was further processed by solid-phase extraction (SPE) clean-up using 96-Well Oasis® HLB Plates. Six SPE washing steps were applied to remove matrix compounds after which the growth promoters were eluted and analysed using UHPLC-MS/MS. To achieve lower detection levels and to reduce LC-solvent consumption, a narrow-bore column with an internal diameter of 1 mm was used, instead of the conventional 2.1 mm. During analysis, the mass spectrometer was operated in negative and positive ionisation mode (ion switching). The newly developed method was validated according to the Commission Decision 2002/657. The results demonstrate that the method meets the criteria as established in this Commission Decision. The precision of the method for exogenous steroids varies between 85 and 115%, the CCα for the compounds ranges from 0.1–0.9 μg kg^?1 and the expanded measurement uncertainty was lower than 36%. Compared to our current in-house methods with analysis times of 2 days for a maximum of 24 samples, the new method offers improved sample throughput (96 samples in less than 24 h) and lower detection limits.     

Rural living in city and countryside: Demand and supply in the Netherlands

Rural living has great appeal among urban residents in the Netherlands. It echoes the rural idyll. Furthermore, there is a demand for rural living in or near urban areas, in the so-called pseudo-countryside. This paper investigates the demand for rural living. In addition, this paper seeks to find out how and to what extent suppliers in the housing market accommodate that demand. Besides building rural residential environments, suppliers try to influence preferences for rural housing through marketing techniques. Where possible, developers build certain types of houses for which they know there is a demand, as that yields the highest profits. Yet the supply of rural residential environments does not meet the demand. The tension between the two components can partly be explained by restrictive government policies. The creation of a pseudo-countryside, a residential environment with the characteristics of the countryside but not located there, might be a compromise.     

Surveillance of adenoviruses and noroviruses in European recreational waters

Exposure to human pathogenic viruses in recreational waters has been shown to cause disease outbreaks. In the context of Article 14 of the revised European Bathing Waters Directive 2006/7/EC (rBWD, CEU, 2006) a Europe-wide surveillance study was carried out to determine the frequency of occurrence of two human enteric viruses in recreational waters. Adenoviruses were selected based on their near-universal shedding and environmental survival, and noroviruses (NoV) selected as being the most prevalent gastroenteritis agent worldwide. Concentration of marine and freshwater samples was done by adsorption/elution followed by molecular detection by (RT)-PCR. Out of 1410 samples, 553 (39.2%) were positive for one or more of the target viruses. Adenoviruses, detected in 36.4% of samples, were more prevalent than noroviruses (9.4%), with 3.5% GI and 6.2% GII, some samples being positive for both GI and GII. Of 513 human adenovirus-positive samples, 63 (12.3%) were also norovirus-positive, whereas 69 (7.7%) norovirus-positive samples were adenovirus-negative. More freshwater samples than marine water samples were virus-positive. Out of a small selection of samples tested for adenovirus infectivity, approximately one-quarter were positive. Sixty percent of 132 nested-PCR adenovirus-positive samples analysed by quantitative PCR gave a mean value of over 3000 genome copies per L of water. The simultaneous detection of infectious adenovirus and of adenovirus and NoV by (RT)PCR suggests that the presence of infectious viruses in recreational waters may constitute a public health risk upon exposure. These studies support the case for considering adenoviruses as an indicator of bathing water quality.