Rose Marie Pangborn

The effect of oral stimulation on human parotid salivary flow rate and alpha-amylase secretion ☆

Unilateral parotid saliva was collected from ten subjects following oral stimulation with water as baseline, and aqueous solutions of starch (2.5, 5.0, and 10%), sucrose (0.1, 0.2, and 0.4 M) sodium chloride (0.075, 0.15, and 0.30 M), and citric acid (0.005, 0.01, and 0.02 M). Salivary flow rate increased with increasing levels of each taste stimulus. At concentrations of equal taste intensity, citric acid evoked the highest flow rate, followed by sodium chloride and sucrose, while starch, in solution, had a minimal effect. Secretion rate patterns for total protein and alpha-amylase mirrored those of flow rate. The total protein and alpha-amylase concentrations of the saliva, and specific activity of alpha-amylase, were influenced by the type but not the concentration of stimulus, with citric acid stimulation resulting in the lowest concentrations and highest specific activity. Sodium ion (Na+) concentration generally increased with increasing stimulated flow rate, while K+, Ca++, and Mg++ concentrations remained relatively constant. Subjects with lower flow rates had a more concentrated saliva than those with high flow, except for Na+ concentration. Oral stimulation resulted in similar changes in protein and alpha-amylase secretion rates for the two groups.

Human saliva and taste responses to acids varying in anions, titratable acidity, and pH

Twenty subjects recorded perceived sourness of solutions of citric + fumaric and of citric + tartaric acids, at pH 3.5 and titratable acidity (TiA) of 4.0 g/l on a moving chart, while parotid saliva flow was recorded via a sialometer . Sourness intensity and flow were greater when citric was the minor acid than when it was dominant. Subjects varied widely in calculated volume of saliva reservoir, but not flow rate (time to 2/3 reservoir vol.). In tartaric-fumaric acid mixtures varying in pH (3.0-3.75) at a constant TiA of 4.0 g/l, and varying in TiA (3.7-4.6 g/l) at a constant pH of 3.5, sourness intensity and parotid flow increased with acidity and decreased with pH. However, eight subjects with a high flow (HF = 1.2 +/- 0.28 g/2 min) and nine subjects with a low flow (LF = 0.43 +/- 0.11 g/2 min) differed widely: (a) In response to variation in stimulus pH and TiA, HF demonstrated marked alteration in flow, but little change in sourness ; LF responded at a lower absolute level, but showed marked changes in sourness and little change in flow; (b) Salivary pH was higher and Na+ was three times greater for the HF than for the LF subjects; and (c) Salivary Ca++ showed a direct relationship with flow and pH among the HF, but an inverse relationship for the LF subjects.

Gustatory, salivary, and oral thermal responses to solutions of sodium chloride at four temperatures

Using eight highly trained Ss, sensitivity to near threshold levels of NaCl was significantly greater at solution temperatures of 22° and 37°C than at 0° or 55°C. Perceived intensity increased linearly with concentration (0.04%–0.64% NaCl) at all four solution temperatures, with the two lower considered slightly more intense than the two higher temperatures. Biomodal distributions were obtained for hedonic judgments at all temperatures, with three Ss showing greater liking and five Ss showing greater disliking of increasing concentrations. Parotid salivary flow was inversely related to the taste sensitivity, i.e., significantly lower flow rates were obtained for the intermediate than for the hot or cold solutions, independent of salt content. When solution temperature was O°C, the minimum temperature of the oral cavity was 9°–20°C; when solution temperature was 55°C, the maximum temperature of the oral cavity was46°–49°C.

Mastication and its influence on human salivary flow and alpha-amylase secretion

Unilateral parotid saliva was collected from ten subjects following oral stimulation with water, chewing on parafilm, mastication of celery and bread, and holding of bread in the mouth. Salivary flow induction was independent of chewing rate. Mastication of bread and celery resulted in higher flow rates than did chewing on parafilm. Although limited to two foods at two weights, the results suggest a possible dependence of flow rate on both the type and weight/size of the stimulus. Mastication increased the secretion rate but not the concentration of protein and alpha-amylase. The rate of alpha-amylase secretion was influenced by mastication in accord with digestive function, in that more secretion was induced by food than by nonfood stimuli, more by bread than by celery, and more by larger than smaller pieces of bread. However, these increases might be related more to the physical characteristics than the composition of the stimuli, e.g., force of chewing, dryness, and surface area.

Human Parotid Secretion in Response to Ethyl Alcohol

Parotid salivary flow increased with increasing concentrations of ethyl alcohol (4.8 to 47.5%), with greater secretion at solution temperatures of 1.5 C than at 22 C. Subjects salivated significantly less when vision was eliminated by black goggles and more in response to 0.15% citric acid than to 20% alcohol, whereas the combination of acid and alcohol elicited responses similar to those from acid alone. Alcohol had a greater sialagogic effect in wine than in water.

Gustatory responses and eating duration of obese and lean adults

Obese adults and matched controls were testing in two main experiments: (1) sweetness perception and preference in lemonade and corresponding judgments of viscosity in apricot nectar, and (2) length of time required to consume palatable and unpalatable foods. No significant differences were obtained between the obese and the lean adults in perception of sweetness intensity or degree of liking for lemonade containing from 6 to 18% sucrose. For apricot nectar, however, the obese subjects demonstrated significantly higher perceived viscosity, a lower degree of liking, and less discrimination than did the lean. Classification of a larger population of female adults, into 20 underweight, 33 normal, and 22 overweight, again resulted in no difference in hedonic responses to lemonade with an expanded sucrose content (2 to 30%). Relative to eating rates, the time required to consume sugar cookies or chocolate milk adulterated with NaCl was inversely related to palatability, with the obese taking longer to consume both. In a subsequent study, times required to consume a carrot stick, a cookie, and 240 ml of chocolate milk were similar between the two groups, although the obese drank the milk significantly faster. No significant correlations were obtained between percent ideal weight and any of the foregoing measurements. The large within-group variation overshadowed between-group differences, suggesting that gustatory and eating responses are related to factors independent of, or additional to, the singular measure of body size.

Regional aroma preferences

Abstract Twenty-two microfragrance strips (18 food-related odours, three non-food odours and one blank) were evaluated for degree of liking in quadruplicate by 30 subjects in each of 16 countries. The structures generated by principal component and cluster analyses of the data were similar to the actual geographic distribution of these countries. It is concluded that degree of liking of food-related aromas varies across regions, probably due to differences in traditional food habits and availability of regional flavour sources.

Preferences and intake measures of salt and sugar, and their relation to personality traits ☆

The inter-relationship of personality with dietary intake of salt and sugar, and with hedonic responses to saltiness and sweetness, was examined among 62 female and 38 male university students. Thirty-five personality traits were assessed using five standard questionnaires: (1) Sixteen Personality Factor (16PF), (2) Jenkins Activity Survey (JAS), (3) Eysenck Personality Questionnaire (EPQ), (4) Multidimensional Health Locus of Control (MHLC), and (5) Sensation Seeking Scale (SSS). Dietary intakes of salty and of sweet foods were estimated from dietary-frequency questionnaires. Hedonic responses to sodium chloride in beef broth and to sucrose in lemonade were measured by category scaling of like/dislike and by ad libitum addition to maximum preference. While subjects with a high salt intake liked saltier broths (p less than 0.05), a similar relationship was not found for sugar intake and sweetness preferences. Hedonic scaling of both saltiness and sweetness was highly related to the ad libitum results. Only a few significant personality effects were observed. The more outgoing individuals liked sweeter lemonade than the more reserved subjects, and subjects who felt they had self-control over their health liked lower levels of salt in broth, while those who felt that chance or others controlled their health liked higher levels. Using personality traits as independent variables in step-wise multiple regression analysis accounted for 13% of the variance in the concentrations of salt and sugar, respectively, which received maximum hedonic responses.

Temporal effectiveness of mouth-rinsing on capsaicin mouth-burn.

Oral rinsing with different solutions significantly reduced mouth-burn of capsaicin solutions in both eaters and noneaters of chili peppers. Cold solutions (5 degrees C) were more effective in reduction of mouth-burn than solutions at 20 degrees C. Sucrose solutions (10%) at 20 degrees C and whole milk at 5 degrees C were equally effective while 5% ethanol was no more effective in mouth-burn reduction than water at 20 degrees C. Reduction of mouth-burn by sucrose was not dose dependent. Noneaters of chili peppers experienced a slightly greater reduction of mouth-burn from sucrose solutions than eaters. Oral rinsing with sweetened milk containing 0 and 10% fat, of varying globule size, resulted in similar degree of mouth-burn reduction. The first (control) sample was rated higher in intensity than subsequent ones, suggesting desensitization, which appears to be due to the interaction of stimulation of chemo-, mechano-, thermo- and gustatory receptors.

Detection and apparent taste intensity of salt-acid mixtures in two media

Gustatory responses to mixtures of sodium chloride and citric acid were measured in two media of dispersion, distilled water and green bean puree, by fifteen experienced Ss. The two psychophysical methods employed, detection thresholds and apparent taste intensity, showed good agreement. Salt sharply depressed apparent sourness in both media, as well as interfering with detection of sourness. Citric acid influenced apparent saltiness in a complex manner, dependent upon concentration, media, method, and tile individual S. In water, lower concentrations of acid generally enhanced and higher concentrations depressed saltiness. Within both media, half the Ss indicated an enhancement of saltiness with increasing acidity and half indicated the reverse. Higher acid levels interfered with detection of saltiness. This biphasic response to binary taste stimuli are discussed and compared with pertinent findings from previous literature.