Astringency and other oral sensations : biological sources of individual variation and association with food and beverage behaviour

Orosensory perception strongly influences liking and consumption of foods and beverages. This thesis examines the influence of biological sources of individual variation on the perception of prototypical orosensory stimuli, food liking, self-reported alcohol liking and consumption, and indices of health. Two orosensory indices were examined: propylthiouracil (PROP) responsiveness, a genetically-mediated index of individual variation associated with enhanced responsiveness to orosensory stimuli often expressed as PROP taster status (PTS); and thermal taster status (TTS), a recently reported index of orosensory responsiveness. Taster status in PTS and/or TTS confers greater responsiveness to most orosensory stimuli. Gender, age, ethnicity, and fungiform papillae (FP) density were not associated with orosensory responsiveness to tastants, an astringent, and a flavour. Unlike PROP responsiveness, FP density was not associated with TTS. Both PROP responsiveness and TTS were associated with increased responsiveness to orosensory stimuli, including temperature and astringency. For PROP, this association did not hold when stimuli were presented at cold or warm temperatures, which are ecologically valid since most foods and beverages are not consumed at ambient temperature. Thermal tasters (TTs), who perceive 'phantom' taste sensations with lingual thermal stimulation, were more responsive to stimuli at both temperatures than thermal non-tasters (TnTs). While PTS, TIS, and gender affected self-reported liking and consumption of some alcoholic beverages, gender associated with the greatest number of beverage types and consumption parameters, with males generally liking and consuming alcoholic beverages more than females. Age and gender were the best predictors of alcoholic beverageAiking and consumption. As expected, .. liking of bitter and fatty foods and cream was inversely related to PROP responsiveness. TTS did not associate with body mass index or waist circumference, and contrary to previous studies, neither did PROP responsiveness. Taken together, TnTs' greater liking of cooked fruits and vegetables and high alcohol, and astringent alcoholic beverages than TTs suggests differences between TTS groups may be driven by perceived temperature and texture. Neither an interaction between PTS and TTS nor a TTS effect on PROP responsiveness was observed, suggesting these two indices of individual variation exert their influences on orosensory perception independently.

Characterisation and optimisation of the flavour of health-promoting, plantderived bitterants in functional beverages.

Flavour is a combination of taste, odour, and chemesthetic sensations. Close associations exist between these sensory modalities, and thus, the overall flavour of a food or beverage product can change when the intensity of one or more of these sensations is altered. Strategies to modify flavour are often utilized by the food industry, and are central to the engineering of new and reformulated products. For functional food and beverages, flavour modification is particularly important, as fortifying agents can elicit high levels of less than desirable sensations, such as bitterness and astringency. The application of various flavour modifying strategies can decrease the perceived intensity of these sensations, and in tum, improve the sensory profile of the product. This collection of studies describes the sensory characteristics of experimental functional beverages fortified with trans-resveratrol, (+)-catechin, and/or caffeine, and examines the impact of novel flavour modifying strategies on the perceived flavour of these beverages. In the first study, results demonstrate that the flavour profile of Cabemet Sauvignon wines fortified with 20 mglL and 200 mg/L of trans-resveratrol is not perceived as different compared to control wine (0 mglL). However, Riesling wine fortified with 200 mg/L is perceived as significantly higher in bitterness compared to 20 mglL and control. For some functional food formulations, alternative strategies for flavour modification are needed. Traditional methods, such as the addition of sucrose and sodium chloride, may decrease the perceived 'healthiness' of a product, and thus, may be sub-optimal. In a second study, high and low concentrations of five different bitter inhibiting compounds - 'bitter blockers' - (B-cyclodextrin, homoeridictyol sodium salt, carboxymethylcellulose - low viscosity, zinc sulfate, magnesium sulfate) were tested for their efficacy towards decreasing the bitterness of high and low concentrations of caffeine and (+)catechin - two health-relevant, plant-derived bitterants. B-cyclodextrin and homoeridictyol sodium salt were the most effective blockers at decreasing (+ )-catechin and caffeine, respectively. In addition to bitter blockers, additional flavour modifying strategies, either alone or in combination - may also be successful in functional food formulations. Both sucrose and rebaudioside A - a plant-derived sweetener - were effective at decreasing the bitterness of (+)catechin. When added to (+)-catechin along with B-cyc1odextrin, both sweeteners provided the most effective decrease in bitterness compared to binary, ternary, or quaternary mixtures of (+)catechin together with bitter blockers, sweeteners, andlor odourants. The perceived intensity of sensations elicited by sweeteners and odourants was not affected by the addition of bitter blockers, and thus, their impact within these complex matrices is minimal. In addition, withinmodal (taste-taste) compared to cross-modal (taste-odour) sensory interactions were more effective at decreasing the bitterness of (+ )-catechin. Overall, results from these studies demonstrate that certain novel, alternative flavour modifying approaches may be successful towards lowering the bitterness and astringency elicited by (+ )-catechin and caffeine in aqueous solutions.

An investigation into the oxidation of organic sulphides, organic selenides and simple hydrocarbons by Mortierella isabellina NRRL 1757

The work presented in this thesis is divided into three separate sections 4!> Each' 'section is involved wi th a different problem, however all three are involved with a microbial oxidation of a substrate~ A series of 'aryl substituted phenyl a.nd be,nzyl methyl sulphides were oxidized to the corre~pondi~g sulphoxides by 'Mo:rtierellai's'a'b'e'llina NRR.L17'S7 @ For this enzymic Qxidation, based on 180 labeled experiments, the oxygen atom is derived fr'orn the atmosphere and not from water. By way of an u~.traviolet analysis, the rates of oxidation, in terms of sulphox~ de appearance, were obtained and correlated with the Hatnmett p s~grna constants for the phenyl methyl sulphide series. A value of -0.67 was obtained and, is interpreted in terms of a mechanism of oxidation that involves an electrophilic attack on the sulphide sulphur by an enzymic ironoxygen activated complex and the conversion of the resulti!lg sulphur cation to sulphoxide. A series of alkyl phenyl selen~des have been incubated with the fu~gi, Aspergillus niger ATCC9l42, Aspergillus fO'etidus NRRL 337, MIIJisabellina NF.RLl757 and'He'lminth'osparium sp'ecies NRRL 4671 @l These fu?gi have been reported to be capable of carrying out the efficient oxidation of sulphide to sulphoxide, but in no case was there any evidence to supp'ort the occurrence of a microbialox,idation. A more extensive inves·t~gation was carried out with'M,e 'i's'a'b'e'l'l'i'na, this fu~gus was capable of oxidizing the correspondi~g sulphides to sulphoxi.de·s·$ Usi:ng a 1abel.edsubstra.te, [Methyl-l4c]-methyl phenyl selenide, the fate of this compound was invest~gated followi!lg an i'ncubation wi th Me isabellina .. BeSUldes th. e l4C-ana1YS1Q S-,'. a quant"ltta"lve selen'lum ana1Y"S1S was carried out with phenyl methyl selenide. These techniques indicate that thesel'enium was capable of enteri!1g thefu!1gal cell ef'ficiently but that s'ome metabolic cleav~ge of the seleni'um-carbon bond' may take plac'e Ie The l3c NMR shifts were assigned to the synthesized alkyl phenyl sulphides and selenides@ The final section involved the incubation ofethylben~ zene and p-e:rtr.hyltoluene wi th'M ~ 'isab'e'llina NRRL 17574b Followi~ g this incubation an hydroxylated product was isolated from the medium. The lH NMR and mass spectral data identify the products as I-phenylethanol and p-methyl-l-phenylethanol. Employi!lg a ch'iral shift re~gent,tri~ (3-heptafluorobutyl-dcamphorato)'- europium III, the enantiomeric puri ty of these products was invest~gated. An optical rotation measurement of I-phenylethanol was in ~greement with the results obtained with the chiral shift re~gen,te 'M.isabe'l'lina is capable of carryi~g out an hydroxylation of ethylbenzene and p-ethyltoluene at the ~ position.

Exchange reactions of organic halides and organo-silicon compounds with boron tribromide and boron triiodide

Reactions of the boron halides with organic halides and organo-silicon compounds have been investigated. The results show exchange of halogens between the BX3 (X = Br# 1) and the organic halidef exchange of the halogen of the C-X bond being proved. The rates of halogen exchange vary. Reaction of the heavier halides with organo-silicon compounds indicated that the silicon-carbon bonds ruptured in the absence of electronegative atom attached to the silicon. The presence of an electronegative atom (halogen or oxygen) attached to the silicon causes the bond between the silicon and the electronegative atom to be preferentially broken. Products of exchange reactions of the boron halides and the organic halides or the organo-silicon compounds were studied by use of 1H NMR and GC/MS. From these results some possible mechanisms for the exchange reactions are postulated, but further work is indicated to prove the real courses of the reactions

Kinetic and mechanistic studies for the molybdenum- catalyzed oxidation of organic sulfides and olefins by t- DuO2H

This research was focussed on the effects of light, solvent and substituents in the molybdenum-catalyzed oxidation of phenylmethyl sulfides with t-Bu02H and on the effect of light in the molybdenum-catalyzed epoxidation of l-octene with t-Bu02H. It was shown that the Mo(CO)6-catalyzed oxidation of phenylmethyl sulfide with t-Bu02H~ at 35°C, proceeds 278 times faster underUV light than under laboratory lighting, whereas the Mo02(acac)2-catalyzed oxidation proceeds only 1.7 times faster under UV light than under normal laboratory lighting. The difference between the activities of both catalysts was explained by the formation of the catalytically active species, Mo(VI). The formation of the Mo(VI) species, from Mo(CO)6 was observed from the IR spectrum of Mo(CO)6 in the carbonyl region. The Mo(CO)6-catalyzed epoxidation of l-octene with t-Bu02H showed that the reaction proceeded 4.6 times faster under UV light than in the dark or under normal laboratory lighting; the rates of epoxidations were found to be the same in the dark and under normal laboratory lighting. The kinetics of the epoxidations of l-octene with t-Bu02H, catalyzed by Mo02(acac)2 were found to be complicated; after fast initial rates, the epoxidation rates decreased with time. The effect of phenylmethyl sulfide on the Mo(CO)6-catalyzed epoxidation of l-octene waS studied. It was shown that instead of phenylmethyl sulfide, phenylmethyl sulfone, which formed rapidly at 85°C, lowered the reaction rate. The epoxidation of l-octene was found to be 2.5 times faster in benzene than in ethanol. The substituent effect on the Mo02(acac)2-catalyzed oxidations of p-OH, p-CHgO, P-CH3' p-H, p-Cl, p-Br, p-CHgCO, p-HCO and P-N02 substituted phenylmethyl sulfides were studied. The oxidations followed second order kinetics for each case; first order dependency on catalyst concentration was also observed in the oxidation of p-CHgOPhSMeand PhSMe. It was found that electron-donating groups on the para position of phenylmethyl sulfide increased the rate of reaction, while electronwithdrawing groups caused the reaction rate to decrease. The reaction constants 0 were determined by using 0, 0- and 0* constants. The rate effects were paralleled by the activation energies for oxidation. The decomposition of t-Bu02H in the presence of M.o (CO)6, Mo02 (acac)2 and VO(acac)2 was studied. The rates of decomposition were found to be very small compared to the oxidation rates at high concentration of catalysis. The relative rates of the Mo02(acac)2-catalyzed oxidation of p-N02PhSMe by t-Bu02H in the presence of either p-CH30PhSMe or PhSMe clearly show that PhSMe and p-CHgOPhSMe act as co-catalysts in the oxidation of p-N02PhSMe. Benzene, mesity1ene and cyclohexane were used to determine the effect of solvent in the Mo02 (acac)2 and Mo(CO)6-catalyzed oxidation of phenylmethyl sulfide. The results showed that in the absence of hydroxylic solvent, a second molecule of t-Bu02H was involved in the transition state. The complexation of the solvent with the catalyst could not be explained.The oxidations of diphenyl sulfoxide catalyzed by VO(acac)2, Mo(CO)6 and Mo02(acac)2 showed that VO(acac)2 catalyzed the oxidation faster than Mo(CO)6 and Mo02 (acac)2_ Moreover, the Mo(CO)6-catalyzed oxidation of diphenyl sulfoxide proceeded under UV light at 35°C.

Studies of some cocondensations of nickel atoms with unsaturated organic ligands and with mixed ligand systems

The cocondensation of nickel with a number of unsaturated ligands was studied, as was the cocondensation with a number of mixed ligand systems. Enamines were found not to react with nickel while acrylonitrile was polymerized. In the mixed ligand syst.ems different products were obtained than when the ligands were cocondensed individually. Cocondensations of benzyl halide/allyl halide mixtures gave unstable products that were not observed when the halides were cocondensed individually. The effect of Kao-Wool insulation on nickel/benzyl halide cocondensations was found to be significant. Kao-Wool caused the bulk of the benzyl halide to be polymeri zed to a number of poly-benzylic species. An alkali metal reactor was designed for the evaporation of sodium and potassium atoms into cold solutions of metal halide and an or ganic substrate. This apparatus was used to synthesize Ni(P¢3 )3' but proved unsuccessful for synthesizing a nickel-enamine compound.

Kinetic and product studies for the oxidtion of organic sulfides and sulfoxides in the presence of transition metal complexes

Rates and products of the oxidation of diphenyl sulfide, phenyl methyl sulfide, p-chlorophenyl methyl sulfide and diphenyl sulfoxide have been determined. Oxidants included t-Bu02H alone, t-Bu02H plus molybdenum or vanadium catalysts and the molybdenum peroxo complex Mo0(02)2*HMPT. Reactions were chiefly carried out in ethanol at temperatures ranging from 20° to 65°C. Oxidation of diphenyl sulfide by t-Bu02H in absolute ethanol at 65°C followed second-order kinetics with k2 = 5.61 x 10 G M~1s"1, and yielded only diphenyl sulfoxide. The Mo(C0)g-catalyzed reaction gave both the sulfoxide and the sulfone with consecutive third-order kinetics. Rate = k3[Mo][t-Bu02H][Ph2S] + k^[Mo][t-Bu02H][Ph2S0], where log k3 = 12.62 - 18500/RT, and log k^ = 10.73 - 17400/RT. In the absence of diphenyl sulfide, diphenyl sulfoxide did not react with t-Bu02H plus molybdenum catalysts, but was oxidized by t-Bu02H-V0(acac)2. The uncatalyzed oxidation of phenyl methyl sulfide by t-Bu02H in absolute ethanol at 65°C gave a second-order rate constant, k = 3.48 x 10~"5 M^s""1. With added Mo(C0)g, the product was mainly phenyl methyl sulfoxide; Rate = k3[Mo][t-Bu02H][PhSCH3] where log k3 = 22.0 - 44500/RT. Both diphenyl sulfide and diphenyl sulfoxide react readily with the molybdenum peroxy complex, Mo0(02)2'HMPT in absolute ethanol at 35°C, yielding diphenyl sulfone. The observed features are mainly in agreement with the literature on metal ion-catalyzed oxidations of organic compounds by hydroperoxides. These indicate the formation of an active catalyst and the complexation of t-Bu02H with the catalyst. However, the relatively large difference between the activation energies for diphenyl sulfide and phenyl methyl sulfide, and the non-reactivity of diphenyl sulfoxide suggest the involvement of sulfide in the production of an active species.

Reactions of steroidal epoxides with strong organic bases and an investigation into the syntheses of some labelled pregnane derivatives

Reactions of 5,6- and 4,5-epoxycholestane derivatives with strong bases were investigated. Epoxidation of 3a-acetoxycholest-5-ene also gave a new compound along with the anticipated epoxides. Interconversions of the latter were observed. Some possible mechanisms of its formation and rearrangements have been pIioposed. No reaction was observed with any of the 5,6- and 4,5-steroidal epoxides employed in the present study, using potassium tertiary butoxide under refluxing conditions. n-Butyllithium reacted only with 5,6-epoxycholestanes bearing a ketal moiety at the C3 carbon. Opening of the ketal group was observed with n-butyllithium in the case of a ~-epoxide. The reaction was also investigated in the absence of epoxide functionality. A possible mechanism for the opening of ketal group has been proposed. Lithium diethylamide (LDEA) was found effective in rearranging 5,6- and 4,5-epoxides to their ~orresponding allylic alcohols. These rearrangements presumably proceed via syn-eliminations, however the possibility of a corresponding anti-elimination has not been eliminated. A substituent effect of various functional groups (R = H, OH, OCH2CH20) at C3 has-been observed on product distribution in the LDEApromoted rearrangements of the corresponding epoxides. No reaction of these epoxides was observed with lithium diisopropylamide (LDA) • In the second part of the project, several attempts were made towards the sYRthesis of deoxycorticoste~one~17,2l,2l~d3' a compound desirable for the 2l-dehydroxylation studies of deoxycorticosterone. Several routes were investigated, and some deuterium labelled pregnane derivatives were prepared in this regard. Microbial 21-hydroxylation of progesteronel7,21,21,2l- d4 by ~ niger led to loss of deuterium from C21 of the product. An effort was made to hydroxylate progesterone microbially under neutral condtions.

Seventeenth Annual Masters of Food and Wine Program 2003

A page from the program from the Seventeenth Annual Masters of Food and Wine ceremonies. Donald Ziraldo and Karl Kaiser are on the list of "Winemakers of 2003".

List of goods including pots, food and nails ordered by Robert Nelles

List of goods including pots, food and nails ordered by Robert Nelles (2 ½ pages, handwritten). The item is stained and slightly torn, but legible, July 4, 1824.