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PubMed2003

Interactions of soluble peptides and proteins from skeletal muscle on the release of volatile compounds.

The ability of skeletal dipeptides (carnosine and anserine) and a sarcoplasmic protein (myoglobin) to interact with key flavor compounds (hexanal, octanal, methional, 2-pentanone, 2-methylbutanal, and 3-methylbutanal) has been studied using the solid phase microextraction (SPME) technique. Conditions for SPME analysis (fiber coating, sampling time, and linearity of detection) were optimized. The effect of pH on the binding was also investigated. Thermodynamic models were applied to evaluate the binding parameters n (number of binding sites), K (affinity constant), and DeltaG (Gibb's free energy) to all of the flavor compounds studied, and they showed an absence of cooperative effect. Carnosine was the peptide with the highest affinity for all of the volatile compounds except 2-pentanone. Its interaction with hexanal and methional was significantly affected by pH. Anserine showed a lower level of interactions with hexanal, methional, 2-methylbutanal, and 3-methylbutanal, whereas myoglobin interacted with only hexanal and 2-methylbutanal. Differences in aroma retention can thus result in different sensory perceptions of muscle foods.

Aldehydes↗
PubMed1989

Possible explanations for excess weight gains in pregnancy: an animal model.

An animal study was designed to address the reasons for excess pregnancy-associated weight gains. Forty-eight adult female rats were divided into two diet groups: a bland chow group and a chow plus glucose solution group. Half of each group was impregnated. Body weight, consumption of both foods, and water consumption were measured daily before, during, and after pregnancy. During pregnancy and after delivery, animals from each food-by-pregnancy group were killed, and adipose tissue analyses were performed. During pregnancy and during lactation, pregnant rats with two foods consumed more glucose solution and gained more adipose tissue with larger cells than did any other group. Taking both studies together, pregnancy is accompanied by sweet food consumption increases and can lead to adipose tissue gains in subjects not influenced by psychological variables.

Adipose Tissue↗
PubMed1999

Effect of ascorbic acid on iron release from the emulsifier interface and on the oxidative flavor deterioration in fish oil enriched mayonnaise.

This research examines the effect of ascorbic acid (0-800 ppm) on the sensory perception of mayonnaises containing 16% fish oil and on the levels of iron and copper in the aqueous phase. Ascorbic acid increased the formation of fishy off-flavors in fresh mayonnaise. Simultaneously, the iron concentration increased from below the detection limit (1.8 microM) to 34 microM in the aqueous phase of mayonnaises. Model mayonnaises with various concentrations of egg yolk (1-7% w/w) and ascorbic acid (0-8000 ppm) were prepared. Iron concentrations in the aqueous phase increased with increasing ascorbic acid levels, whereas iron concentrations in the assumed interfacial layer decreased. It is proposed that ascorbic acid is able to complex and reduce Fe(3+) to Fe(2+) from phosvitin in the egg yolk, whereby iron is released from the interface. The ascorbic acid-iron complex subsequently reacts with lipid hydroperoxides, resulting in increased lipid oxidation and in the immediate formation of rancid and fishy off-flavors.

Antioxidants↗
PubMedDate not supplied

[Sugar triggers our reward-system. Sweets release opiates which stimulates the appetite for sucrose--insulin can depress it].

The consumption of sweet food has increased in Sweden, as in other Western countries. The type of food item has changed. The sweet is dominated by soft drinks. Appetite regulation for sucrose has been described in experimental animal models. It has been found that opioids stimulate appetite for sucrose. At the same time sucrose releases endogenous opioids so that a triggering of sucrose consumption occurs. Insulin has been shown to decrease sucrose intake by blocking the opioid response. Sucrose addiction has been described in rat model. With a concentrated sucrose solution to drink an opioid dependence developed with 1) increased consumption of sucrose 2) abstinence symptoms with no sucrose and 3) anxiety with an opiate blocker. Sucrose addiction in man has not been described in the scientific literature. There is an increased liking of sweets with alcoholic persons, which may be significant to support a strongly rewarding effect of sucrose, also in man. We should limit the access to sweet foods, in particular the sweet drinks. Insulin and insulin sensitivity may be an important factor to restrict the intake of sweet food.

Animals↗
PubMed1993

Individual differences in sensory preferences for fat in model sweet dairy products.

Sensory preferences for fat in foods are influenced both by subject characteristics and by the nature of the food stimulus. Hedonic responses to sugar/fat mixtures depend on strong interactions between perceptions of the two ingredients, including tactile as well as gustatory effects. Fat-containing liquid and solid foods, and dessert-type sugar/fat mixtures produce different hedonic response profiles. Body weight, weight history and the presence of eating disorders are associated with differences in hedonic responsiveness to fat among women. This inter-subject variability in hedonic response profiles mandates the use of novel techniques for data analysis. Conventional hedonic response curves mask between-subject differences. Individual patterns of hedonic responses to sugar/fat mixtures are better represented by frequency distributions of maximum hedonic responses or of individual optimal sugar-to-fat ratios.

Adult↗
PubMed2004

Sensory and rheological properties of transgenically and chemically modified starch ingredients as evaluated in a food product model.

Starches derived from five genetically modified potato lines, two chemically modified potato starches and two native starches from potato and maize were subjected to physical and chemical analyses and their functionality evaluated in a milk-based food product model. The transgenic starches were specifically modified with respect to amylopectin chain length and phosphorous content by suppression of the starch branching enzyme and overexpression of glycogen branching enzyme. Transgenic starches with long amylopectin chains and high phosphorous content had increased gelatinisation temperatures, produced gels with a higher tendency to retrograde and a low freeze/thaw stability as compared to starches with shorter amylopectin chains and lower phosphorous content. The textural properties of the food product model prepared from genetically and chemically modified starches were characterised by sensory and rheological analyses. To clearly visualise the effects of the modifications, data was evaluated by radar plots and multiple regression analysis (chemometrics). Genetically modified potato starches with longer amylopectin chains and increased phosphorous content gave a more gelled and a shorter texture as compared to starches with shorter amylopectin chains and decreased phosphorous content. Acetylated and hydroxypropylated potato starches gave sticky and stringy textures. Correlations between rheology parameters and sensory parameters were found. The sensory parameter stringy/long could be predicted from the rheological data.

Amylopectin↗
PubMed1977

[Electrogustometric threshold in diabete and chronic ethylism. Survey on 230 patients (author's transl)].

This study completes a previous one in which the authors tested the electrogustometric threshold in 300 normal subjects used as controls. The collected datas has been computerized on a programable calculator according to a lognormal model. Comparison between the electrogustometric threshold in diabetic patients, ethylic ones and controls demonstrate that they are statistically different. More than a half of the diabetics and ethylics have abnormaly high electrogustometric thresholds. The responses have been studied as a function of the evolution of the disease, of the clinical form and of gravity. Diabete and chronic ethylism do not disturb the gustatic function at the same speed and with the same intensity: one year evolution is at least necessary for diabetics, and ten years for ethylics in order to detect abnormal electrogustometric thresholds. But if the action of ethylic intoxication is slower, it determines the most important gustometric deteriorations.

Alcoholism↗
PubMed2002

Closure of the Venus flytrap module of mGlu8 receptor and the activation process: Insights from mutations converting antagonists into agonists.

Ca2+, pheromones, sweet taste compounds, and the main neurotransmitters glutamate and gamma-aminobutyric acid activate G protein-coupled receptors (GPCRs) that constitute the GPCR family 3. These receptors are dimers, and each subunit has a large extracellular domain called a Venus flytrap module (VFTM), where agonists bind. This module is connected to a heptahelical domain that activates G proteins. Recently, the structure of the dimer of mGlu1 VFTMs revealed two important conformational changes resulting from glutamate binding. First, agonists can stabilize a closed state of at least one VFTM in the dimer. Second, the relative orientation of the two VFTMs in the dimer is different in the presence of glutamate, such that their C-terminal ends (which are connected to the G protein-activating heptahelical domain) become closer by more than 20 A. This latter change in orientation has been proposed to play a key role in receptor activation. To elucidate the respective role of VFTM closure and the change in orientation of the VFTMs in family 3 GPCR activation, we analyzed the mechanism of action of the mGlu8 receptor antagonists ACPT-II and MAP4. Molecular modeling studies suggest that these two compounds prevent the closure of the mGlu8 VFTM because of ionic and steric hindrance, respectively. We show here that the replacement of the residues responsible for these hindrances (Asp-309 and Tyr-227, respectively) by Ala allows ACPT-II or MAP4 to fully activate the receptors. These data are consistent with the requirement of the VFTM closure for family 3 GPCR activation.

Amino Acid Sequence↗
PubMed2001

Betel quid chewing among Bangladeshi adolescents living in east London.

OBJECTIVES: Ascertain level and predictors of betel quid (pan) chewing in Bangladeshi adolescents. DESIGN: Cross sectional questionnaire study. SETTING: Bangladeshi cultural centres in East London. SAMPLE: Consecutive adolescents attending 4 randomly selected centres. METHOD: Self-completed questionnaire. RESULTS: 204 (70%) of 290 teenagers invited to participate did so. Fifty-eight (28%) chewed pan; 30 (51%) of whom chewed on most days. The median age of first chewing was 9 years. Only 7 (2%) added tobacco to their quids. Pan chewers tended to come from lower socio-economic status families, liked the taste of pan and were less inclined to think that it adversely affected their appearance or that it could cause cancer. CONCLUSIONS: The prevalence of pan chewing was lower than that found among adults reported in earlier studies in the UK. This reduction in the level of pan chewing could be attributed to acculturation. Few teenagers knew about the association between pan chewing and cancer but the widespread concern about the effect of pan chewing on the appearance of their mouth suggests this is a useful health promotion message within common risk/health factor approach.

Adolescent↗
PubMed2005

Functional MRI detection of activation in the primary gustatory cortices in humans.

Magnetoencephalography (MEG) has recently revealed that the transitions between the parietal operculum (Pop) and the insula (area G) and the ventral end of the central sulcus (cs) were activated with the shortest latency by instrumental gustatory stimulation, which suggests that the location of the primary gustatory area is in these two regions. However, studies using other noninvasive brain-imaging methods such as positron-emission tomography or functional magnetic resonance imaging (fMRI) with manual application of tastants into the mouth have been unable to confirm this. The present study examined cortical activation by repetitive stimulation of the tongue tip with 1 M NaCl with a computer-controlled stimulator and used fMRI to detect it. In individual brains, activations were detected with multiple comparisons (false discovery rate) across the whole brain corrected (threshold at P < 0.05) at both area G and frontal operculum (Fop) in 8 of 11 subjects and at the rolandic operculum (Rop) in 7 subjects. Activations were also found at the ventral end of the cs (n = 3). Group analysis with random-effect models (multiple comparison using familywise error in regions of interest, P < 0.02) revealed activation at area G in both hemispheres and in the Fop, Rop, and ventral end of the cs on the left side. The present study revealed no activation on the gyrus of the external cerebral surface except for the Rop. Taking MEG findings into consideration, the present findings strongly indicate that the primary gustatory area is present at both the transition between the Pop and insula and the Rop including the gray matter within a ventral part of the cs.

Adult↗
PubMed2004

Evaluation of meat born lactic acid bacteria as protective cultures for the biopreservation of cooked meat products.

In this study, 91 strains, originating from meat products, were subjected to a step-by-step screening and characterisation to search for potential protective cultures to be used in the cooked cured meat industry. Strains were first tested on their homofermentative and psychrotrophic character and salt tolerance. Secondly, the antibacterial capacities towards Listeria monocytogenes, Leuconostoc mesenteroides, Leuconostoc carnosum and Brochotrix thermosphacta were determined in an agar spot test. In total, 38% of the tested strains were inhibitory towards all indicator strains. However, 91%, 88% and 74% of the strains could inhibit, respectively, L. monocytogenes, B. thermosphacta and Leuc. mesenteroides. Finally, 12 strains, with the highest antibacterial capacities, were evaluated on their competitive nature by comparing their growth rate, acidifying character and lactic acid production at 7 degrees C under anaerobic conditions in a liquid broth. All 12 strains, except for a bacteriocin producing Lactobacillus plantarum strain and the lactocin S producing Lactobacillus sakei 148, combined a fast growth rate with a deep and rapid acidification caused by the production of high levels of lactic acid. The 12 selected strains were then further investigated for their growth capacity on a model cooked ham product to establish whether the presence of these cultures on the ham did not negatively influence the sensory properties of the ham. All strains grew in 6 days at 7 degrees C from a level of 10(5)-10(6) to 10(7)-10(8) cfu/g and again the bacteriocin producing L. plantarum strain was the slowest growing strain. As the glucose level of the model cooked ham product was low (0.09+/-0.03%), growth of the putative protective cultures resulted in glucose depletion and a limited lactic acid production and accompanying pH decrease. Cooked ham inoculated with isolates 13E, 10A, 14A (all three identified as L. sakei subsp. carnosus by SDS-PAGE) and with strains L. sakei 148 (LS5) and L. sakei subsp. carnosus SAGA 777 (LS8) were not rejected by the sensory panel at the 34th day of the vacuum packaged storage at 7 degrees C. Therefore, these strains could have potential for the use as protective culture in cooked meat products.

Animals↗
PubMed1993

Sweet-tasting protein monellin is related to the cystatin family of thiol proteinase inhibitors.

The structure of the intensely sweet protein monellin, isolated from an African berry, and the structures of two thiol proteinase inhibitors, cystatin and stefin B, are found to be very similar. An alignment of sequences of monellin and the inhibitors, deduced from the structural comparisons, has been extended to include other members of the cystatin superfamily. There is a significant homology (up to 23% identical residues) with oryzacystatins, the only well defined plant cystatins. These results clearly indicate that monellin is a close relative of cystatins. Monellin and cystatins do not have the same sequence in the regions homologous to the cystatin active site. It is suggested here, however, that this region in monellin may be essential for a function in situ, because one of the loops comprising this part of the structure is found to be cleaved.

Amino Acid Sequence↗
PubMed2003

Prior exposure to phencyclidine decreases voluntary sucrose consumption and operant performance for food reward.

Prior exposure to the psychotomimetic drug phencyclidine (PCP) produces a number of schizophrenia-like behaviors in animals. The goal of the present study was to determine whether prior exposure to PCP produces decreased reward function, thereby modeling one aspect of negative schizophrenic symptomatology. To this aim, the consequences of prior exposure to PCP were assessed on two types of appetitive consumptive behavior. In the first set of experiments, the effects of PCP (15 mg/kg, 20 h before testing) on sucrose consumption were tested for three consecutive days under conditions of deprivation and nondeprivation. In the deprivation condition, animals were water deprived for 4 h prior to injection of PCP or saline (SAL). Twenty hours following the injection (24 h after the onset of water deprivation), animals were allowed access to either 5% sucrose or water for 30 min. In the nondeprivation condition, 5% sucrose consumption was measured for 30 min, 20 h after PCP or SAL injection and water consumption was measured during the 23.5 h preceding sucrose consumption. PCP decreased both sucrose and water consumption under deprivation conditions on the second and third day of testing but selectively decreased sucrose consumption under nondeprivation conditions on all three testing days. LiCl (50 mg/kg, 20 h before testing) did not significantly reduce sucrose consumption in the nondeprivation paradigm, indicating that the effect of PCP was not due to conditioned taste aversion. In the second experiment, PCP (15 mg/kg, 20 h before testing) decreased operant performance when animals were switched from a continuous reinforcement schedule of food delivery to a fixed ratio (FR4) schedule. Apomorphine (APO, 30 microg/kg, 30 min before testing), a positive control, induced a similar performance deficit. However, the PCP-induced deficit was not apparent until the third day of FR4 testing while the APO deficit was apparent on the first day. The effects of PCP on sucrose consumption demonstrate PCP-induced decreases in reward function. However, the delayed appearance of the PCP-induced decrease in operant performance suggests that these results may be better explained by a PCP-induced attentional deficit, also characteristic of schizophrenic psychopathology.

Animals↗
PubMed2002

Safety and clinical effects of topical histatin gels in humans with experimental gingivitis.

BACKGROUND: Our research group has recently reported that exogenously applied histatins can inhibit plaque accumulation and gingival inflammation in a preclinical canine model (Paquette et al. 1997). OBJECTIVES: The aims of the present double-blinded, randomized, controlled clinical trial were to evaluate the safety and toxicity of three histatin (P-113) concentrations in gel formulations, and to assess potential clinical benefit on the development of gingivitis (partial mouth design). MATERIAL AND METHODS: One hundred and six healthy subjects were recruited and brought to optimal gingival health (GI < 0.5) prior to treatment initiation. At baseline, eligible subjects were randomized for one of the following treatments: (1) placebo; (2) 0.0625% P-113; (3) 0.125% P-113; and (4) 0.375% P-113. Patients self-applied gels twice daily for 29 days to the maxillary right quadrant with the use of customized stents. In addition, patients deferred all oral hygiene procedures within this quadrant for the duration of the treatment period. Safety was assessed in terms of physical and oral examinations, clinical laboratory testing and recording of adverse events. Clinical indices were measured weekly and included gingival index (GI), plaque index (PI) and %BOP. RESULTS: All study formulations were well tolerated by patients, and no differences in adverse event occurrences were noted among treatment groups, including taste alteration or staining. For the intent-to-treat population, significantly smaller %BOP changes were noted in subjects treated with 0.0625, 0.125 and 0.375% P-113 gels (17.4, 18.18 and 17.9%, respectively) versus placebo (28.0%) (p < 0.05) at day 29. When groups were compared in terms of per cent responders (change in %BOP < 15 or < 20%), P-113 treatment groups exhibited a higher frequency of response, especially for the 0.0625 and 0.125% P-113 formulations (p < 0.05). Although no statistically significant intergroup differences were noted for changes in GI or PI among all subjects (intent-to-treat population), significantly smaller changes in PI at day 22 were observed among compliant individuals (defined as subjects using > 60% of the target gel mass) administering P-113 gels as compared with compliant placebo subjects (p < 0.05). CONCLUSIONS: These data indicate safety and tolerance of P-113 gels for topical oral use in human subjects. These data also suggest that P-113 gels administered twice daily may reduce experimental gingivitis as measured with bleeding on probing in humans.

Adult↗
PubMed2002

Idiopathic dysgeusia; an open trial of alpha lipoic acid (ALA) therapy.

We selected two homogenous groups, each of 22 patients with idiopathic dysgeusia, an altered perception of taste, matched for age and sex, for an open trial of alpha lipoic acid compared with placebo. The 22 patients in the study group were treated with alpha lipoic acid for 2 months. The 22 patients in the control group were treated for 2 months with carboxymethylcellulose. The latter group was then treated with alpha lipoic acid for 2 months. The results showed significant symptomatic improvements compared with placebo, in both groups of patients with dysgeusia treated with alpha lipoic acid, suggesting that idiopathic dysgeusia may be a neuropathy comparable to the burning mouth syndrome.

Adolescent↗
PubMed2003

Excess of symptoms among radiographers.

BACKGROUND: The prevalence and occupational determinants of miscellaneous symptoms referred to as "Darkroom disease" was compared between radiographers and physiotherapists working in British Columbia, Canada. METHODS: The participation rate for the mailout questionnaire survey was 66.1%. A small subset underwent spirometry and methacholine challenge testing. RESULTS: Radiographers had a higher prevalence of most symptoms, with an extreme odds ratio of 11.4 for chemical/metallic taste. The percentage of radiographers with non-specific bronchial hyperresponsiveness (NSBHR) was 3 times higher than that of physiotherapists, although the comparison was not statistically significant. Reporting inadequate ventilation, frequently detecting the odor of X-ray processing chemicals and cleaning up spills within the past 12 months were highly associated with most of the symptoms. CONCLUSIONS: Our results suggest that differences in the prevalence of symptoms represent a complex process, both in exposure and response to the many constituents found in radiographic processing chemicals. Objective testing of health outcomes and more refined exposure measurements are recommended to further investigate occupational health problems of radiographers.

Adult↗
PubMed1996

Observational conditioning of food valence in humans.

It has been suggested that the observation of a model consuming a food (CS) and facially expressing either to like or to dislike (US') the food, may be a sufficient condition to bring about a change in the valence of the food for the observer. Unfortunately, up to now this hypothesis has not been investigated in a straightforward manner. In this study, during acquisition, children consumed a series of evaluatively neutral colored and flavored drinks, while simultaneously they watched a videotaped model synchronically drinking identical drinks and facially expressing his evaluation (neutral or dislike) of the liquids. In one condition, the presence of a particular flavor in the drinks was designated to function as the CS+ or the CS-, whereas in the other condition it was the color of the drinks which was the critical CS+ or CS-. Next, the children evaluated a series of drinks containing the critical CSs. A clear evaluative learning effect was obtained when the flavor but not when the color of the drinks was systematically paired with the model's facial expression of dislike. Moreover, the flavor conditioning effect was dependent on the presence in the test drinks of the local context cues (c.q. the colors of the drinks) which were used during acquisition. Finally a double dissociation was observed between explicit beliefs and the "evaluative knowledge" expressed in the ratings of the drinks, in that none of the children in the CS = Flavor groups evidenced any explicit knowledge about the crucial CS-US' contingency but showed evaluative conditioning, whereas the majority of the children in CS = Color groups were aware of the CS-US' relation but failed to demonstrate an evaluative CS-/CS-differentiation.

Attitude↗
PubMed2003

Comparative morphological study of the lingual papillae and their connective tissue cores of the koala.

The stereo structure of each lingual papilla of the koala has a similar structure to that of various other animal species: the koala has a lingual prominence (intermolar prominence) with larger filiform papillae. (A lingual prominence is a characteristic in herbivorous animals.) The external form and connective tissue core (CTC) of the filiform papillae of koalas consist of one large main process and several smaller accessory processes. (These are similar to carnivorous animals.) Fungiform CTC have a thick dome-like structure, with several taste buds on the top. There are three vallate papillae: one central midline and two laterally located vallate papillae. The central vallate papilla has a posterior pouch lined with ciliated and non-ciliated epithelial cells. Long conical papillae are distributed in the posterior lateral area where foliate papillae are distributed in many other animal species. (Finger-like papillae are seen in dog and cat instead of foliate papillae.) It may be suggested that the tongue of the koala evolved in a special environment in Australia. Even though it has still retained special features similar to those of carnivorous cats and dogs it has evolved to resemble the tongues of herbivorous animals.

Animals↗