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Biomedical subjects

J E Frijters

Publications and source records attributed to J E Frijters.

At least 19 recordsLinked to original sources
PubMed1994

Perceptual interactions in mixtures containing bitter tasting substances.

Mixtures of Quinine HCl and NaCl elicit heterogeneous taste percepts. Each such percept consists of a bitter and a salt sensation. Using functional measurement in combination with a two-stimulus procedures, it was found that the NaCl suppresses the QHCl bitterness and that QHCl has almost no suppressive effect on NaCl saltiness. In addition, it was shown that the total intensity of the mixture percept is almost identical to the sum of the intensities of the bitterness and saltiness sensations-within-the-percept. As was found in earlier experiments with mixtures of other tastants, central sensory integration within a heterogeneous percept seems to be a fairly simple additive process.

Adult↗
PubMed1993

Perceptual integration in heterogeneous taste percepts.

When mixtures of dissimilar tasting compounds are perceived, specific taste sensations are integrated into a percept. Four models are evaluated that were designed to predict the total taste intensity of a mixture percept from the total taste intensities of the unmixed components or from the specific taste intensities of the components within the mixture percept. The predictions of the two dominant component models are inferior to those made by the two other models. Predictions made by the vector summation model are accurate, but the model contains theoretical weaknesses that make it an invalid psychological integration model. The sum of sensations model predicts total intensity with an accuracy similar to the vector summation model, but it is more parsimonious. Furthermore, it can account for all of the empirical phenomena observed.

Citrates↗
PubMed1992

Sweetness does not habituate during a sip-and-spit experiment.

In gravitational flow studies, the estimated saltiness of a NaCl/sucrose mixture increases after repetitive stimulations with sucrose. This increment is hypothesized to be the consequence of successive contrast and suppression release. According to the successive contrast hypothesis, the saltiness of the mixture percept is overestimated because its salty taste stands out against the preceding sweet tastes. The release of saltiness from suppression is supposed to originate from habituation to sweet stimuli. In the present study, the saltiness of a NaCl/sucrose mixture was judged after repetitive stimulations with sucrose using a sip-and-spit procedure. The increment in saltiness estimates after repeated stimulations with sucrose could be fully accounted for by successive contrast. No suppression release was observed. Differences in experimental procedure (the degree of experimental control, the subjects' arousal level, the variation in the proximal stimuli, the area of the tongue stimulated, and the subjective intensities of the habituating stimuli) that may affect the rate of habituation, are suggested as potential sources of the differences between the gravitational flow studies and the present one.

Adolescent↗
PubMed1992

Contextual and sequential effects on judgments of sweetness intensity.

Presenting stimuli from skewed concentration distributions affects mean responses on category scales. However, if the number of categories on the response scale is increased, the degree of separation between the mean responses obtained for a positively as opposed to a negatively skewed concentration distribution diminishes. The present study investigates the effect of skewed concentration distributions upon ratings on a line scale and compares it to the context effect found for a 7-point category scale. In addition, sequential dependencies between consecutive stimuli and responses are investigated in order to assess their relevance in taste-intensity scaling studies. The context effects are similar for the 7-point category scale and for the line scale. The analyses of sequential effects show that both preceding responses and preceding stimuli affect current responses. However, since these two factors work in opposite directions, only a small contrast effect from the previous stimulus is significant in an overall analysis. The present study shows that even though the overall sequential effects between consecutive stimuli and responses are small, the effect of experimental context may be considerable. Since subjective context is established at the beginning of a session and sequential dependencies operate throughout the whole session, it is argued that contextual and sequential effects are only indirectly related.

Adult↗
PubMed1991

The effectiveness of different sweeteners in suppressing citric acid sourness.

The exact mechanism that causes taste suppression in a perceptually heterogeneous mixture, and the locus of that mechanism, are as yet unknown. The present study was designed to explore the idea that mixture suppression is a perceptual phenomenon and not the result of physical, chemical, or receptor-substance interactions. An investigation was carried out as to whether perceptually similar taste stimuli give rise to the same sensory interactions when mixed with a substance of a different taste quality. In the first study, five different sweeteners (sucrose, fructose, aspartame, saccharin, and sorbitol) were matched in perceived sweetness intensity, in order to obtain five perceptually similar stimuli. Every equisweet sweetener concentration was mixed with each of four citric acid concentrations. In a second study, the sourness-suppressing effects of two sweeteners, sucrose and aspartame, were compared at four different concentration levels. Sourness scale values of unmixed citric acid, the unmixed sweeteners, and the citric acid/sweetener mixtures were assessed with a functional measurement approach in combination with a two-stimulus procedure. The equisweet sweeteners were equally effective in suppressing the perceived sourness intensity of citric acid over the concentration range used. The side tastes of the sweeteners, if present, did not have a substantial effect on the degree of sourness suppression.

Adult↗
PubMed1988

Assessment of the taste interaction between two qualitatively similar-tasting substances: a comparison between comparison rules.

The taste interaction between sucrose and fructose was assessed by using three different comparison procedures: the summated response comparison, the factorial plot comparison, and the equimolar comparison rule. The perceived sweetness intensities were obtained on a ratio scale by using a functional measurement approach in combination with a two-stimulus procedure. The conclusions obtained from each of the three comparison rules were identical. The taste interaction between sucrose and fructose could be explained to a large extent, but not completely, by the apparent taste "interactions" within sucrose and fructose as single substances. It is argued that the apparent taste interaction within a large number of single sugars and between two of these sugars in a mixture is somewhat synergistic at low sweetness levels, additive at intermediate sweetness levels, and suppressive at high sweetness levels.

Adolescent↗
PubMed1988

Changes in body mass index in young adults in relation to number of life events experienced.

As part of an extensive longitudinal study, the effect of experiencing few or many life events on the development of the body mass index (BMI = weight/height2) over periods of 1 year and 2 years was examined in 350 men and 395 women, 20-35 years of age. Body weight was measured and a life event questionnaire referring to the preceding 6 months was completed every 6 months from spring 1981 through spring 1984. The change in BMI of subjects who experienced few or many life events was compared with the change in BMI of subjects who experienced an intermediate number of life events (the intermediate group). During the first year of follow-up, several subgroups of men and women who experienced many life events showed a gain in body mass. In several subgroups of men who experienced few life events a comparable effect occurred. After another year of follow-up this gain in body mass had disappeared in almost all subgroups. In the subgroup of men that tried to reduce their body weight by dieting during the follow-up period, the gain in body mass following few or many life events seemed to be permanent. In conclusion, the gain in body mass that may occur following the experience of many life events in women, seems to be effectively counterbalanced by regulatory mechanisms. In men, however, the experience of few or many life events may play a part in the aetiology of overweight.

Adult↗
PubMed1987

The equiratio taste mixture model successfully predicts the sensory response to the sweetness intensity of complex mixtures of sugars and sugar alcohols.

The equiratio taste mixture model was originally developed for the prediction of psychophysical power functions of equiratio mixtures of substances that have a similar taste and that also exhibit mutual cross adaptation. Earlier studies have shown that the model is valid for mixtures of sugars and/or sugar alcohols. Two experiments are reported in which it is questioned whether the psychophysical functions of mixtures of higher physical complexity can be predicted by the model. In the first experiment the psychophysical power functions of binary and quaternary equiratio mixture types were determined experimentally and compared to those predicted by the generalized model. In the second, similar, experiment quaternary and eight-component mixture types were examined. The method of magnitude estimation, in combination with the sip and spit procedure, was used. The functions predicted by the model were almost identical to the functions established on the basis of the experimental data. These results reconfirm that the gustatory modality operates like an 'averaging' system when processing this kind of mixture. It is argued that for other kind of mixtures the model will predict incorrectly. The status of the equiratio mixture model is discussed.

Adolescent↗
PubMed1986

Life events, emotional eating and change in body mass index.

The results are reported of a longitudinal study on effects of negative life events on change in body mass index (BMI; weight/height2 (kg/m2)) in men and women classified as either low or high emotional eaters. It was predicted that emotional eating and negative life events would have an interaction effect on change in BMI. Low emotional eaters would gain less weight and high emotional eaters would gain more weight after experiencing negative life events, than those who had not experienced such events. For men, emotional eating and negative life events were found to have a significant interaction effect on change in BMI 6 months after the assessment of life events on the first, but not on the second assessment date in the same study. Data on the long-term effects of negative life events indicate that the significant interaction effect found was not an artefact. For women, no such interaction effects were found. Thus, it is concluded that the hypothesis was confirmed to some extent in the men, but not in the women.

Adult↗
PubMed1985

Eating behavior, personality traits and body mass in women.

In an exploratory study in women, the relationships between scales of emotional eating, external eating, and restrained eating, and body mass index (BMI = weight/height2) were studied, as well as the interrelationships between these three eating behavior components. In addition, the relationships between the three eating behavior scales and 19 personality scales were examined. Finally, differences between obese and latent obese women with respect to eating behavior and personality were investigated. Significant relationships were found between BMI and emotional eating, and between BMI and external eating/perceived hunger, but not between BMI and Restrained Eating. Also, restrained eating was found not to be related to the other two eating behavior components. Of the three eating behavior components, emotional eating was shown to have the clearest relationships with a number of personality traits. No difference was observed between the eating behavior of latent obese and obese women, but these groups differed as to a number of personality traits. These results are discussed in terms of consequences for prevalent theories on restrained, external, and emotional eating.

Adult↗
PubMed1984

Sweetness intensity perception and sweetness pleasantness in women varying in reported restraint of eating.

In previous studies on the breakdown of restrained eating it was implicitly assumed that individuals reporting different degrees of pre-experimental restrained eating have identical preferences for the taste and odour of foods. This hypothesis was tested with 23 women classified as either high, medium or low restrained eaters on the basis of their scores on a Dutch 'Restrained Eating Scale'. Individual psychophysical and psychohedonic functions for sweetness and pleasantness of sucrose were determined. From the mean group values it was concluded that there is no relationship between the degree of self-reported restrained eating and perceived sweetness intensity, nor is there a relationship between the degree of self-reported restrained eating and maximally preferred sweetness intensity.

Adult↗
PubMed1983

The construction and prediction of psychophysical power functions for the sweetness of equiratio sugar mixtures.

Psychophysical taste mixture models describe the relationship between the perceived intensities of the unmixed components and the intensity of the mixture. Three of these models are discussed. As all of these appear either to be internally inconsistent or lack sufficient generality, a simple alternative model has been developed especially for the prediction of the intensity of equiratio mixtures. This model was experimentally tested with glucose-fructose mixtures. On the basis of the data obtained it is shown that a psychophysical equiratio mixture function can be constructed in the same way as a power function for a single compound. The results show that the new mixture model can predict the functions for equiratio mixtures with great precision. Implications for mixture interaction phenomena are discussed.

Adult↗
PubMed1983

Obesity in young Dutch adults: I, socio-demographic variables and body mass index.

The simultaneous contribution of various socio-demographic variables to body mass index (BMI; weight/height) was studied in young adults in three age groups (19-21, 24-26 and 29-31 yr) in a Dutch population. Medians of the BMI of males (n = 1765) and females (n = 2092) were 23.1 and 21.8 kg/m2, respectively. The prevalence of severe obesity (BMI greater than or equal to 30.0 kg/m2) was 2 per cent in both sexes. There was a positive relationship between age and BMI, while level of education and level of father's occupation were inversely related to BMI in both sexes. Married females who had given birth to two or more children weighed more than those with one or no children. The mean BMI of the males in the rural area was higher than that of the males in the urban area. Both the Lutheran males and females weighed more than the non-Lutherans. The mean BMI was lower in males attending church more frequently than once a month. There were no independent relationships between BMI and the other socio-demographic variables (marital status, main daily occupation, size of family of origin and birth order) in either sex. In conclusion, it can be stated that age and socio-economic status were the most important socio-demographic determinants of BMI. Socio-economic status can be useful in directed prevention of obesity.

Adult↗