A complex relationship among chemical concentration, detection threshold and suprathreshold intensity of bitter compounds

Detection thresholds and psychophysical curves were established for caffeine, quinine-HCl (QHCl), and propylthiouracil (PROP) in a sample of 33 subjects (28 female mean age 24 &plusmn; 4). The mean detection threshold (&plusmn;standard error) for caffeine, QHCl, and PROP was 1.2 &plusmn; 0.12, 0.0083 &plusmn; 0.001, and 0.088 &plusmn; 0.07 mM, respectively. Pearson product&ndash;moment analysis revealed no significant correlations between detection thresholds of the compounds. Psychophysical curves were constructed for each bitter compound over 6 concentrations. There were significant correlations between incremental points of the individual psychophysical curves for QHCl and PROP. Regarding caffeine, there was a specific concentration (6 mM) below and above which the incremental steps in bitterness were correlated. Between compounds, analysis of psychophysical curves revealed no correlations with PROP, but there were significant correlations between the bitterness of caffeine and QHCl at higher concentrations on the psychophysical curve (P &lt; 0.05). Correlation analysis of detection threshold and suprathreshold intensity within a compound revealed a significant correlation between PROP threshold and suprathreshold intensity (r = 0.46&ndash;0.4, P &lt; 0.05), a significant negative correlation for QHCl (r = &ndash;0.33 to &ndash;0.4, P &lt; 0.05), and no correlation for caffeine. The results suggest a complex relationship between chemical concentration, detection threshold, and suprathreshold intensity.<br /

Bitterness suppression with zinc sulfate and na-cyclamate: a model of combined peripheral and central neural approaches to flavor modification

Purpose Zinc sulfate is known to inhibit the bitterness of the antimalarial agent quinine [R. S. J. Keast. The effect of zinc on human taste perception. J. Food Sci. 68:1871&ndash;1877 (2003)]. In the present work, we investigated whether zinc sulfate would inhibit other bitter-tasting compounds and pharmaceuticals. The utility of zinc as a general bitterness inhibitor is compromised, however, by the fact that it is also a good sweetness inhibitor [R. S. J. Keast, T. Canty, and P. A. S. Breslin. Oral zinc sulfate solutions inhibit sweet taste perception. Chem. Senses 29:513&ndash;521 (2004)] and would interfere with the taste of complex formulations. Yet, zinc sulfate does not inhibit the sweetener Na-cyclamate. Thus, we determined whether a mixture of zinc sulfate and Na-cyclamate would be a particularly effective combination for bitterness inhibition (Zn) and masking (cyclamate). Method We used human taste psychophysical procedures with chemical solutions to assess bitterness blocking. Results Zinc sulfate significantly inhibited the bitterness of quinine&ndash;HCl, Tetralone, and denatonium benzoate (DB) (p &lt; 0.05), but had no significant effect on the bitterness of sucrose octa-acetate, pseudoephedrine (PSE), and dextromethorphan. A second experiment examined the influence of zinc sulfate on bittersweet mixtures. The bitter compounds were DB and PSE, and the sweeteners were sucrose (inhibited by 25 mM zinc sulfate) and Na-cyclamate (not inhibited by zinc sulfate). The combination of zinc sulfate and Na-cyclamate most effectively inhibited DB bitterness (86%) (p &lt; 0.0016), whereas the mixture\u27s inhibition of PSE bitterness was not different from that of Na-cyclamate alone. Conclusion A combination of Na-cyclamate and zinc sulfate was most effective at inhibiting bitterness. Thus, the combined use of peripheral oral and central cognitive bitterness reduction strategies should be particularly effective for improving the flavor profile of bitter-tasting foods and pharmaceutical formulations. <br /

The concentration of oleocanthal in olive oil waste

The aim of this study was to determine the concentration of oleocanthal in olive pomace waste and compare this to its concentration in extra-virgin olive oil (EVOO). The concentration of oleocanthal in freshly pressed EVOO and its subsequent waste was analysed at early, mid and late season harvests. Oleocanthal concentrations were quantified using high-performance liquid chromatography&ndash;mass spectrometry. In oil, oleocanthal concentration was as follows: 123.24 &plusmn; 6.48 mg kg&macr;&sup1;1 in early harvest, 114.20 &plusmn; 17.42 mg kg&macr;&sup1; in mid harvest and 152.22 &plusmn; 10.54 mg kg&macr;&sup1; in late harvest. Its concentration in waste was determined to be: 128.25 &plusmn; 11.33 mg kg&macr;&sup1; in early harvest, 112.15 &plusmn; 1.51mg kg&macr;&sup1; in mid harvest and 62.35 &plusmn; 8.00 mg kg&macr;&sup1; in late harvest. Overall, olive pomace waste is a valuable source of oleocanthal.<br /

Cross-sectional study of 24-hour urinary electrolyte excretion and associated health outcomes in a convenience sample of Australian primary schoolchildren: the salt and other nutrients in children (SONIC) study protocol

BACKGROUND: Dietary sodium and potassium are involved in the pathogenesis of cardiovascular disease. Data exploring the cardiovascular outcomes associated with these electrolytes within Australian children is sparse. Furthermore, an objective measure of sodium and potassium intake within this group is lacking. OBJECTIVE: The primary aim of the Salt and Other Nutrient Intakes in Children (&quot;SONIC&quot;) study was to measure sodium and potassium intakes in a sample of primary schoolchildren located in Victoria, Australia, using 24-hour urine collections. Secondary aims were to identify the dietary sources of sodium and potassium, examine the association between these electrolytes and cardiovascular risk factors, and assess children\u27s taste preferences and saltiness perception of manufactured foods. METHODS: A cross-sectional study was conducted in a convenience sample of schoolchildren attending primary schools in Victoria, Australia. Participants completed one 24-hour urine collection, which was analyzed for sodium, potassium, and creatinine. Completeness of collections was assessed using collection time, total volume, and urinary creatinine. One 24-hour dietary recall was completed to assess dietary intake. Other data collected included blood pressure, body weight, height, waist and hip circumference. Children were also presented with high and low sodium variants of food products and asked to discriminate salt level and choose their preferred variant. Parents provided demographic information and information on use of discretionary salt. Descriptive statistics will be used to describe sodium and potassium intakes. Linear and logistic regression models with clustered robust standard errors will be used to assess the association between electrolyte intake and health outcomes (blood pressure and body mass index/BMI z-score and waist circumference) and to assess differences in taste preference and discrimination between high and low sodium foods, and correlations between preference, sodium intake, and covariates. RESULTS: A total of 780 children across 43 schools participated. The results from this study are expected at the end of 2015. CONCLUSIONS: This study will provide the first objective measure of sodium and potassium intake in Australian schoolchildren and improve our understanding of the relationship of these electrolytes to cardiovascular risk factors. Furthermore, this study will provide insight into child taste preferences and explore related factors. Given the cardiovascular implications of consuming too much sodium and too little potassium, monitoring of these nutrients during childhood is an important public health initiative

Micronutrient supplement use and diet quality in university students

Many national and international public health organisations recommend achieving nutrient adequacy through consumption of a wide variety of nutritious foods. Despite this, dietary supplement sales continue to increase. Understanding the characteristics of micronutrient supplement users and the relationship with diet quality can help develop effective public health interventions to reduce unnecessary consumption of vitamin and mineral supplements. Participants (n = 1306) were a convenience sample of students studying first year food and nutrition. Data was collected via a Food and Diet Questionnaire (FDQ) and a Food Frequency Questionnaire (FFQ). Supplement users were defined as participants who indicated consuming any listed supplement as frequently as once a month or more. Diet quality was assessed using a Dietary Guideline Index (DGI) score. Prevalence of supplement use was high in this study population with 56% of participants reporting supplement use; the most popular supplements consumed were multivitamins (28%) and vitamin C (28%). A higher DGI score was significantly associated with an increased likelihood of supplement use (mean: 105 &plusmn; 18 vs. 109 &plusmn; 17, p = 0.001). Micronutrient supplement use was associated with a higher DGI score, suggesting that supplements are more likely to be used by those who are less likely to require them

Ring-Pattern Dynamics in Smectic-C* and Smectic-C_A* Freely Suspended Liquid Crystal Films

Ring patterns of concentric 2pi-solitons in molecular orientation, form in freely suspended chiral smectic-C films in response to an in-plane rotating electric field. We present measurements of the zero-field relaxation of ring patterns and of the driven dynamics of ring formation under conditions of synchronous winding, and a simple model which enables their quantitative description in low polarization DOBAMBC. In smectic C_A* TFMHPOBC we observe an odd-even layer number effect, with odd number layer films exhibiting order of magnitude slower relaxation rates than even layer films. We show that this rate difference is due to much larger spontaneous polarization in odd number layer films.Comment: 4 RevTeX pgs, 4 eps figures, submitted to Phys. Rev. Let

X-ray absorption spectroscopy systematics at the tungsten L-edge

A series of mononuclear six-coordinate tungsten compounds spanning formal oxidation states from 0 to +VI, largely in a ligand environment of inert chloride and/or phosphine, has been interrogated by tungsten L-edge X-ray absorption spectroscopy. The L-edge spectra of this compound set, comprised of [W&lt;sup&gt;0&lt;/sup&gt;(PMe&lt;sub&gt;3&lt;/sub&gt;)&lt;sub&gt;6&lt;/sub&gt;], [W&lt;sup&gt;II&lt;/sup&gt;Cl&lt;sub&gt;2&lt;/sub&gt;(PMePh&lt;sub&gt;2&lt;/sub&gt;)&lt;sub&gt;4&lt;/sub&gt;], [W&lt;sup&gt;III&lt;/sup&gt;Cl&lt;sub&gt;2&lt;/sub&gt;(dppe)&lt;sub&gt;2&lt;/sub&gt;][PF&lt;sub&gt;6&lt;/sub&gt;] (dppe = 1,2-bis(diphenylphosphino)ethane), [W&lt;sup&gt;IV&lt;/sup&gt;Cl&lt;sub&gt;4&lt;/sub&gt;(PMePh&lt;sub&gt;2&lt;/sub&gt;)&lt;sub&gt;2&lt;/sub&gt;], [W&lt;sup&gt;V&lt;/sup&gt;(NPh)Cl&lt;sub&gt;3&lt;/sub&gt;(PMe&lt;sub&gt;3&lt;/sub&gt;)&lt;sub&gt;2&lt;/sub&gt;], and [W&lt;sup&gt;VI&lt;/sup&gt;Cl&lt;sub&gt;6&lt;/sub&gt;] correlate with formal oxidation state and have usefulness as references for the interpretation of the L-edge spectra of tungsten compounds with redox-active ligands and ambiguous electronic structure descriptions. The utility of these spectra arises from the combined correlation of the estimated branching ratio (EBR) of the L&lt;sub&gt;3,2&lt;/sub&gt;-edges and the L&lt;sub&gt;1&lt;/sub&gt; rising-edge energy with metal Z&lt;sub&gt;eff&lt;/sub&gt;, thereby permitting an assessment of effective metal oxidation state. An application of these reference spectra is illustrated by their use as backdrop for the L-edge X-ray absorption spectra of [W&lt;sup&gt;IV&lt;/sup&gt;(mdt)&lt;sub&gt;2&lt;/sub&gt;(CO)&lt;sub&gt;2&lt;/sub&gt;] and [W&lt;sup&gt;IV&lt;/sup&gt;(mdt)&lt;sub&gt;2&lt;/sub&gt;(CN)&lt;sub&gt;2&lt;/sub&gt;]&lt;sup&gt;2–&lt;/sup&gt; (mdt&lt;sup&gt;2–&lt;/sup&gt; = 1,2-dimethylethene-1,2-dithiolate), which shows that both compounds are effectively W&lt;sup&gt;IV&lt;/sup&gt; species. Use of metal L-edge XAS to assess a compound of uncertain formulation requires: 1) Placement of that data within the context of spectra offered by unambiguous calibrant compounds, preferably with the same coordination number and similar metal ligand distances. Such spectra assist in defining upper and/or lower limits for metal Z&lt;sub&gt;eff&lt;/sub&gt; in the species of interest; 2) Evaluation of that data in conjunction with information from other physical methods, especially ligand K-edge XAS; 3) Increased care in interpretation if strong π-acceptor ligands, particularly CO, or π-donor ligands are present. The electron-withdrawing/donating nature of these ligand types, combined with relatively short metal-ligand distances, exaggerate the difference between formal oxidation state and metal Z&lt;sub&gt;eff&lt;/sub&gt; or, as in the case of [W&lt;sup&gt;IV&lt;/sup&gt;(mdt)&lt;sub&gt;2&lt;/sub&gt;(CO)&lt;sub&gt;2&lt;/sub&gt;], add other subtlety by modulating the redox level of other ligands in the coordination sphere

The influence of caffeine on energy content of sugar-sweetened beverages : the caffeine–calorie effect

Background/Objectives: Caffeine is a mildly addictive psychoactive chemical and controversial additive to sugar-sweetened beverages (SSBs). The objective of this study is to assess if removal of caffeine from SSBs allows co-removal of sucrose (energy) without affecting flavour of SSBs, and if removal of caffeine could potentially affect population weight gain. Subjects/Methods: The research comprised of three studies; study 1 used three-alternate forced choice and paired comparison tests to establish detection thresholds for caffeine in water and sucrose solution (subjects, n ¼ 63), and to determine if caffeine suppressed sweetness. Study 2 (subjects, n ¼ 30) examined the proportion of sucrose that could be co-removed with caffeine from SSBs without affecting the flavour of the SSBs. Study 3 applied validated coefficients to estimate the impact on the weight of the United States population if there was no caffeine in SSBs. Results: Detection threshold for caffeine in water was higher (1.09±0.08 mM) than the detection threshold for caffeine in sucrose solution (0.49 ± 0.04 mM), and a paired comparison test revealed caffeine significantly reduced the sweetness of sucrose (Po0.001). Removing caffeine from SSBs allowed co-removal of 10.3% sucrose without affecting flavour of the SSBs, equating to 116 kJ per 500 ml serving. The effect of this on body weight in adults and children would be 0.600 and 0.142 kg, which are equivalent to 2.08 and 1.10 years of observed existing trends in weight gain, respectively. Conclusion: These data suggest the extra energy in SSBs as a result of caffeine&apos;s effect on sweetness may be associated with adult and child weight gain

A long winter for the Red Queen: rethinking the evolution of seasonal migration

This paper advances an hypothesis that the primary adaptive driver of seasonal migration is maintenance of site fidelity to familiar breeding locations. We argue that seasonal migration is therefore principally an adaptation for geographic persistence when confronted with seasonality – analogous to hibernation, freeze tolerance, or other organismal adaptations to cyclically fluctuating environments. These ideas stand in contrast to traditional views that bird migration evolved as an adaptive dispersal strategy for exploiting new breeding areas and avoiding competitors. Our synthesis is supported by a large body of research on avian breeding biology that demonstrates the reproductive benefits of breeding‐site fidelity. Conceptualizing migration as an adaptation for persistence places new emphasis on understanding the evolutionary trade‐offs between migratory behaviour and other adaptations to fluctuating environments both within and across species. Seasonality‐induced departures from breeding areas, coupled with the reproductive benefits of maintaining breeding‐site fidelity, also provide a mechanism for explaining the evolution of migration that is agnostic to the geographic origin of migratory lineages (i.e. temperate or tropical). Thus, our framework reconciles much of the conflict in previous research on the historical biogeography of migratory species. Although migratory behaviour and geographic range change fluidly and rapidly in many populations, we argue that the loss of plasticity for migration via canalization is an overlooked aspect of the evolutionary dynamics of migration and helps explain the idiosyncratic distributions and migratory routes of long‐distance migrants. Our synthesis, which revolves around the insight that migratory organisms travel long distances simply to stay in the same place, provides a necessary evolutionary context for understanding historical biogeographic patterns in migratory lineages as well as the ecological dynamics of migratory connectivity between breeding and non‐breeding locations.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149253/1/brv12476.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149253/2/brv12476_am.pd