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At least 721 records · Page 40Linked to original sources
PubMed2004

Long life: a matter of taste (and smell).

Insulin/IGF signaling has emerged as a central regulator of metazoan aging. In C. elegans, insulin-like peptides are expressed predominately in neurons. Alcedo and Kenyon demonstrate that removal of specific gustatory and olfactory neurons result in longer life, suggesting that metazoan longevity is influenced by sensory perception.

Animals↗
PubMed2004

The smell of sleep.

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Portraits as Topic↗
PubMed2006

Synthesis and structure determination of covalent conjugates formed from the sulfury-roasty-smelling 2-furfurylthiol and di- or trihydroxybenzenes and their identification in coffee brew.

Recent investigations demonstrated that the reaction of odor-active thiols such as 2-furfurylthiol with thermally generated chlorogenic acid degradation products is responsible for the rapid aroma staling of coffee beverages. To get a clear understanding of the molecular mechanisms underlying this aroma staling, the existence of putative phenol/thiol conjugates needs to be verified in coffee. The aim of the present study was therefore to synthesize such conjugates for use as reference substances for LC-MS screening of coffee. To achieve this, catechol, 3-methyl-, 4-methyl-, and 4-ethylcatechol, pyrogallol, hydroxyhydroquinone, 5-O-caffeoylquinic acid, and caffeic acid, respectively, were reacted with 2-furfurylthiol in the presence of iron(III) chloride and air oxygen. After purification, the structures of 25 phenol/thiol conjugates were identified by means of LC-MS/MS and 1D/2D NMR experiments. Using these compounds as reference materials, four conjugates, namely, 3-((2-furylmethyl)sulfanyl)catechol, 3-((2-furylmethyl)sulfanyl)-5-ethylcatechol, 4-((2-furylmethyl)sulfanyl)hydroxyhydroquinone, and 3,4-bis((2-furylmethyl)sulfanyl) hydroxyhydroquinone, were identified for the first time in coffee brew by means of HPLC-MS/MS(MRM). These findings clearly demonstrate catechol, 4-ethylcatechol, and hydroxyhydroquinone as the primary thiol trapping agents involved in the aroma staling of coffee beverages.

Chromatography, High Pressure Liquid↗
PubMed1998

New and Convenient Syntheses of the Important Roasty, Popcorn-like Smelling Food Aroma Compounds 2-Acetyl-1-pyrroline and 2-Acetyltetrahydropyridine from Their Corresponding Cyclic alpha-Amino Acids.

Novel straightforward syntheses have been developed supplying the important food odorants 2-acetyl-1-pyrroline (AP) and 2-acetyltetrahydropyridine (ATHP) in high yields. The four-step reaction sequence starts from the N-shielded cyclic alpha-amino acids L-proline and pipecolinic acid, respectively, which, in the first step, are converted into the N-shielded 2-acetyl derivatives. Removing the shielding group with trifluoroacetic acid afforded the 2-acetylpyrrolidine and 2-acetylpiperidine trifluoroacetate, respectively, which, upon increasing the pH of their aqueous solutions to 7.0, are spontaneously oxidized in high yields into AP (43% based on L-proline) or ATHP (35% based on pipecolinic acid), respectively, by air oxygen. The latter step is an important hint at the last step in the yet unclear formation pathways of both odorants in foodstuffs.

Journal Article↗
PubMed1996

Penicillin Acylase-Mediated Synthesis of 2-Acetyl-1-pyrroline and of 2-Propionyl-1-pyrroline, Key Roast-Smelling Odorants in Food. Inclusion Complexes with beta-Cyclodextrin and Their NMR and MS Characterization.

The synthesis of the strong natural roast odorants 1 and 2 is achieved from the C-6 isomeric alcohols 16 and 21 via the acetylenic C-6 and C-7 amines 8 and 9. Key step in the process is the hydrolysis of the N-phenylacetamides 12 and 13 by means of immobilized penicillin acylase, which affords the 1-amino-4,5-diketones 14 and 15, spontaneously ring closing to 1 and 2. These latter compounds form inclusion complexes with beta-cyclodextrin, as demonstrated by NMR measurements in deuterated water and FAB-MS spectra.

Journal Article↗
PubMed1997

Dependence by any other name smells just as sweet: reply to van der Velde and van der Heijden (1997)

The hypothesis that people selectively attend to entire objects predicts that all attributes of an object will be reported either very accurately (if the object was attended) or very inaccurately (if it was unattended). Hence, reports of object attributes should show positive dependence. M. Monheit and J. Johnston (1994) have confirmed this prediction. F. van der Velde and A. H. C. van der Heijden (1997), however, have argued that dependence in the overall data is spurious. They advocate a model that partitions the data into 2 subsets, 1 for perception trials and 1 for guessing trials, each of which separately exhibits independence. Here, the authors argue that this treatment of guessing is misguided because, in effect, guesses are discarded rather than treated as failures of perception. The Monheit and Johnston analysis, on the other hand, is fundamentally sound and demonstrates precisely the kind of dependence predicted by the spatial attention hypothesis.

Attention↗
PubMed2000

Does the rose still smell as sweet? Item variability across test forms and revisions.

This article examines item stability when the same item appears in different contexts. The 1st section considers the assumptions in classical test theory and item response theory concerning the relationship between the item and the trait it is presumed to measure. The 2nd section presents contextualist challenges to the measurement theory assumptions about item properties and shows the instability of item characteristics across different testing contexts. The 3rd section describes methods for checking the relationship between items and traits. Classical test methods, item response methods, and structural equation methods for assessing item stability are reviewed. The instability of item characteristics across contexts should caution researchers to assess, and not assume, that items operate the same way on different test versions. Item instability also indicates the need for a more detailed understanding of the psychological processes that occur between item and answer.

Humans↗
PubMed1922

Smell.

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Journal Article↗