EFFECT OF QUANTITY CONSUMED ON MEASURES OF LIKING FOR SALT CONCENTRATIONS IN SOUP

Two studies are reported on the effect ofingestion on the relative-to-ideal ratings of salt in soup. In the first study there was a reduction in the measure of ideal concentration from pre- to post-ingestion, with subjects consuming the soups ad libitum. However, a measure of ideal concentration derived from several small samples presented in each session agreed well with the final post-ingestion ideal. A measure of most preferred concentration of salt based on total soup consumption was unrelated to the other measures. In the second experiment, the post-ingestion decrease in most preferred salt concentration was replicated when subjects consumed a fixed quantity of soup. The post-ingestion ideal was similar to that derived from rating either several small samples in one session or one single small sample per session.     

Consumption of sugars by Anastrepha suspensa (Diptera: Tephritidae)

We were interested in determining the feeding response of the Caribbean fruit fly, Anastrepha suspensa Loew (Diptera: Tephritidae), to various sugar concentrations to develop an improved bait for adults. We compared the consumption of 0.01-1.00 M concentrations of glucose, fructose, raffinose, and sucrose in no-choice tests for 24-h- and 6-d-old male and female flies. Sucrose was the most consumed sugar or within the most consumed group of sugars at 0.02-0.20 M concentrations. There were no differences in consumption among sugars at 0.01, 0.40, and 1.00 M. Consumption generally increased with increasing sugar concentration except that sucrose consumption peaked at 0.20 M. Twenty-four-hour females consumed less fructose than other sugars; 24-h males consumed more sucrose than fructose or raffinose, with an intermediate response to glucose. Females in the 6-d group consumed more sucrose than the other three sugars, whereas 6-d males exhibited no difference in consumption among sugars. In choice tests, flies consumed more sugar solution than water, but the difference between 0.20 M fructose and water was not significant for 24-h males or 24-h females. In choice tests between 0.20 M fructose and 0.20 M sucrose, both 24-h and 6-d females showed a preference for fructose. Males of both age classes showed no preference. These results indicate that the responses of flies to different sugars can vary by sugar, gender, and age.     

Preferences for nectar sugars in the peacock butterfly, Inachis io

1. Peacock butterflies, Inachis io , were tested experimentally for their preferences for nectar sugars.
2. In tests with different plain sugar solutions (25%, weight to total weight) the butterflies strongly preferred sucrose and fructose over glucose. They also preferred sucrose over fructose.
3. In tests with mixed sugar solutions the butterflies clearly preferred both sucrose-dominant (sucrose : hexoses = 5 : 1) and balanced sugar solutions (sucrose : glucose : fructose = 1 : 1 : 1) over hexose-dominant sugar solutions (sucrose : hexoses = 1 : 5).
4. Females consumed significantly more of the balanced sugar solution than did males.
5. These results are discussed with respect to previous experiments on nectar preferences of butterflies, nectar sugar composition of butterfly-pollinated flowers, and flower preferences, physiological and reproductive aspects of butterflies.     

Nectar concentration preferences and sugar intake in the white-bellied sunbird, <Emphasis Type="Italic">Cinnyris talatala</Emphasis> (Nectariniidae)

Plant nectar is a simple food consumed by many different animals. Preferences regarding its components, especially sugars, have been studied for many species, but the preferences of nectar-feeding birds for different sugar concentrations are less well known than their sugar type preferences. The concentration preferences of white-bellied sunbirds, Cinnyris talatala, were examined using paired solutions of either sucrose or equicaloric 1:1 mixtures of glucose and fructose. Preferences were tested over a broad concentration range of 0.25–2.5 M sucrose equivalents (using 0.25 or 0.5 M differences between pairs). On both sucrose and hexose diets, the higher concentration was preferred up to 1 M, but there were no significant preferences above this concentration, except that birds preferred 1.5 to 2 M sucrose. As with other nectar-feeding vertebrates, the laboratory preferences of sunbirds do not explain the low concentration of their natural nectars. We recorded apparent excess sugar consumption during 6 h preference tests involving concentrated hexose diets; this could be due to digestive constraints or viscosity differences between sucrose and hexose solutions.     

Citric acid production by solid state fermentation using sugarcane bagasse

A solid state fermentation (SSF) method was used to produce citric acid by Aspergillus niger DS 1 using sugarcane bagasse as a carrier and sucrose or molasses based medium as a moistening agent. Initially bagasse and wheat bran were compared as carrier. Bagasse was the most suitable carrier, as it did not show agglomeration after moistening with medium, resulting in better heat and mass transfer during fermentation and higher product yield. Different parameters such as moisture content, particle size, sugar level and methanol concentration of the medium were optimised and 75% moisture level, 31.8 g sugar/100 g dry solid, 4% (v/w) methanol and particles of the size between 1.2 and 1.6 mm were found to be optimal. Sucrose and clarified and non-clarified molasses medium were also tested as moistening agents for SSF and under optimised conditions, 20.2, 19.8 and 17.9 g citric acid /100 g of dry solid with yield of 69.6, 64.5 and 62.4% (based on sugar consumed) was obtained in sucrose, clarified and non-clarified molasses medium respectively, after 9 days of fermentation.     

EFFECT OF YOGURT SWEETNESS ON SENSORY SPECIFIC SATIETY

The objective of this study was to determine if hedonically different sweetness levels in yogurt, determined by the ideal-relative rating methods, affected the consumption of yogurt in a sensory specific satiety test. Fifteen subjects attended a preliminary session, six taste tests and three sensory specific satiety tests. During each taste test, subjects rated yogurt with one of the three levels of sweetness (high, optimum, and low) for six attributes. During each sensory specific satiety test, subjects were offered a large serving of yogurt with one of the sweetness levels. Liking for optimum or high sweet yogurts decreased more after consumption than the liking for the low sweet yogurt, however, the consumption of optimum and high sweet yogurts was also greater, thus confounding the experiment.     

Taste threshold determination and side-preference in captive cockatiels (Nymphicus hollandicus)

The taste thresholds of caged cockatiels (Nymphicus hollandicus) for aqueous solutions of sodium chloride, citric acid, and sucrose were studied using two-choice taste-preference tests. The effects of location on the threshold were tested by putting the flavored solution in either the preferred or non-preferred locations (i.e. sides of cages) and offering water in the opposite location. Four parameters (total consumption, consumption from preferred side, consumption from non-preferred side, and proportion of test solution consumed) were measured at the end of 3-day test periods. Experiments were repeated with increasing concentration of test flavors until intake variables were significantly (p<0.05) affected. The results showed that birds distinguished (p<0.05) between purified water and 0.16 mol l(-1) sodium chloride, 0.36 mol l(-1) sucrose, or pH 5.5 citric acid. The likelihood of detecting a taste threshold was greater for sodium chloride and citric acid when these solutions were placed on the preferred side. In contrast, sucrose sensitivity was greater when this solution was offered on the non-preferred side.     

Effects of sucrose concentrations and fly age on feeding responses and survival of female and male western cherry fruit flies, Rhagoletis indifferens

Abstract. The effects of single meals of different sucrose concentrations on feeding responses and survival of 8–24-h-old, 1–2-, 10–12- and 31–36-day-old female and male western cherry fruit flies, Rhagoletis indifferens Curran, were determined. Feeding time and food consumption response patterns in both sexes within age groups were curvilinear. Feeding times increased as sucrose concentrations increased, and were longest when the sucrose concentration was 100% (dry). Consumption of dilute wet sucrose was low, whereas consumption of concentrated wet sucrose was high. However, consumption of dry, 100% sucrose was also low. One to 2-day-old flies of both sexes that had not previously fed consumed more sucrose foods than unfed 8–24-h-old flies and 10–12- and 31–36-day-old flies that had been starved for 16–24 h. Females consumed more than males, but they consumed the same amount as males per mg bodyweight. When fed single 20% and 60% sucrose meals, 1–2-day-old flies survived longer compared to flies in all other age groups, with 31–36-day-old flies surviving shortest. Despite age-related differences in survival, in general, no sex differences in survival were seen in flies fed sucrose within any age groups, or in flies fed sucrose-yeast, cherry juice and honeydew foods. The results suggest that sugar-feeding behaviours and the energy invested in sugar 'seeking' by both sexes of R. indifferens should be the same throughout life.     

Sugar assimilation and digestive efficiency in Wahlberg's epauletted fruit bat (Epomophorus wahlbergi)

Fruit- and nectar-feeding bats have high energy demands because of the cost of flight, and sugar is a good fuel because it is easily digested and absorbed. This study investigated the digestive efficiency of different sugars at different concentrations in Wahlberg's epauletted fruit bat (Epomophorus wahlbergi). We predicted that the sugar type and concentration would affect the total amount of solution consumed, while the total energy gained and the apparent assimilation efficiency would be high, irrespective of sugar type or concentration. Equicaloric solutions of two sugar types, glucose and sucrose, at low (10%), medium (15%) and high (25%) concentrations were offered in separate trials to bats. Total amount of solution consumed, total energy gained from each solution, and apparent assimilation efficiency, were measured. Bats had higher total volumetric intake of glucose and sucrose at the low concentrations than at the higher concentrations. However, bats maintained similar total energy intake on the respective glucose and sucrose concentrations. Bats were found to have high assimilation efficiencies on both glucose and sucrose irrespective of concentration. As bats used both sugars efficiently to maximize and maintain energy gain, it is expected that they feed opportunistically on fruit in the wild depending on temporal and spatial availability to obtain their energy requirements. Furthermore, fruit with high sucrose or glucose content will be consumed.     

The glucogenic response of a parasitized insect Manduca sexta L. is partially mediated by differential nutrient intake

Induction of gluconeogenesis is accelerated in larvae of the insect Manduca sexta L. parasitized by Cotesia congregata (Say), maintaining the concentration of the blood sugar trehalose, an important nutrient for parasite development. Investigation has demonstrated that when host larvae are offered a choice of diets with varying levels of sucrose and casein, parasitized insects consume a different balance of these nutrients, principally due to a decrease in protein consumption. The result is metabolic homeostasis, with normal unparasitized and parasitized larvae exhibiting similar levels of gluconeogenesis and blood sugar level. In the present study, normal unparasitized and parasitized larvae were maintained on individual chemically defined diets having the balance of protein and carbohydrate consumed by each when offered a dietary choice. Total dietary nutrient, the sum of carbohydrate and protein, was provided at six levels, composed of three pairs of diets. Each diet pair consisting of diets having equivalent overall nutrient ratios of 2:1 and 1:1 casein/sucrose. Host growth and diet consumption were significantly affected by dietary nutrient level and the magnitude of these effects was influenced by parasitism. Due to the effects of dietary nutrient level on diet consumption, none of the unparasitized and parasitized larvae within any of the three diet pairs consumed protein and carbohydrate at the levels predicted by the earlier choice experiments. Among insects on all of the diets, however, two groups of unparasitized and parasitized larvae consumed the expected levels of protein and carbohydrate. In each case, gluconeogenesis, as measured by 13C nuclear magnetic resonance spectroscopy (NMR) analysis of pyruvate cycling and trehalose synthesis from [2-13C]pyruvate, was evident in unparasitized and parasitized insects, confirming the conclusions of the earlier experiments. Generally, all larvae that consumed less than approximately 250 mg of sucrose over the 3-day feeding period, were gluconeogenic, regardless of diet. Differential carbohydrate consumption, therefore, was an important factor in inducing gluconeogenesis in both unparasitized and parasitized insects. The selective 13C enrichment in trehalose displayed by non-gluconeogenic larvae on some diets demonstrated trehalose formation from [2]pyruvate. The absence of net carbohydrate synthesis in these insects was likely due to an elevation of glycolysis. There was no significant effect of diet consumption or parasitism on blood trehalose level. Parasitized larvae displayed higher levels of gluconeogenesis than did unparasitized insects, a finding consistent with the conclusion that blood sugar is rapidly sequestered by developing parasites. The parasite burden, the total number of parasites developing within host larvae, as well as the number of parasites emerging from host larvae to complete development, was significantly less at the lowest dietary nutrient level, but was otherwise similar at all dietary nutrient levels. Moreover, the number of parasites that emerged increased with increasing diet consumption as reflected by host final weight.     

Price elasticity of the demand for sugar sweetened beverages and soft drinks in Mexico

A large and growing body of scientific evidence demonstrates that sugar drinks are harmful to health. Intake of sugar-sweetened beverages (SSB) is a risk factor for obesity and type 2 diabetes. Mexico has one of the largest per capita consumption of soft drinks worldwide and high rates of obesity and diabetes. Fiscal approaches such as taxation have been recommended as a public health policy to reduce SSB consumption. We estimated an almost ideal demand system with linear approximation for beverages and high-energy food by simultaneous equations and derived the own and cross price elasticities for soft drinks and for all SSB (soft drinks, fruit juices, fruit drinks, flavored water and energy drinks). Models were stratified by income quintile and marginality index at the municipality level. Price elasticity for soft drinks was −1.06 and −1.16 for SSB, i.e., a 10% price increase was associated with a decrease in quantity consumed of soft drinks by 10.6% and 11.6% for SSB. A price increase in soft drinks is associated with larger quantity consumed of water, milk, snacks and sugar and a decrease in the consumption of other SSB, candies and traditional snacks. The same was found for SSB except that an increase in price of SSB was associated with a decrease in snacks. Higher elasticities were found among households living in rural areas (for soft drinks), in more marginalized areas and with lower income. Implementation of a tax to soft drinks or to SSB could decrease consumption particularly among the poor. Substitutions and complementarities with other food and beverages should be evaluated to assess the potential impact on total calories consumed.     

Taste responses of Drosophila melanogaster

The amounts of sugar solution consumed by Drosophila melanogaster flies were determined. Starved and desiccated flies of a wild type strain (QA) consume 7?9 × 10^?2 λ of a 0.3 M sucrose solution per fly during the first hour and less later. They consume more of the 0.3 M sucrose solution than of the more diluted and the more concentrated solutions. In preference-aversion tests the flies discriminated between water and various sugar solutions, and between different sugar concentrations. Contrary to other fly species these flies did not prefer 0.05 M fructose over 0.05 M glucose. 0.3–0.5 M NaCl added to 0.1 M sucrose turned a preference over 0.01 sucrose into an aversion. A mutant, Lot-94, selected for its increased consumption of a 1 M NaCl solution was found to consume more of all test solutions. The amount of NaCl that had to be added to 0.1 M sucrose to turn the preference over 0.01 M sucrose by the mutant flies into aversion was not different from that found for the wild type flies.     

Taste perception and diet in individuals with Chinese and European ethnic backgrounds

Relationships between taste perception and diet were investigatedin two ethnic groups. The Chinese subjects (n = 30) were bornin the People's Republic of China and were currently livingin the United States. The U.S. subjects (n = 30) were of Europeanancestry. Psychophysical taste intensity functions for sucrosesolutions, NaCl solutions and NaCl in soup were obtained usingmagnitude matching. Pleasantness ratings for the above stimuli,plus sucrose in cookies and NaCl in crackers were obtained usingcategory rating scales. Three-day dietary records and the frequencyof sweet food consumption were also collected. Chinese subjectsassigned higher pleasantness ratings to the higher concentrationsof sucrose in water and showed a tendency to rate sucrose incookies as tasting more pleasant. These higher pleasantnessratings of sucrose were not reflected in increased sugar intake.The Chinese subjects also assigned higher pleasantness ratingsto and preferred higher concentrations of salt in crackers andthis was reflected in the data from the dietary records. TheChinese Na/Kcal and Na/K ratios were greater than those of theU.S. group.     

Sugar preferences and xylose metabolism of a mammal pollinator, the Namaqua rock mouse (Aethomys namaquensis).

The sugar preferences of 10 Namaqua rock mice, Aethomys namaquensis, were assessed using pairwise combinations of 30% (w/w) solutions of sucrose, glucose, fructose, xylose, and a mixture of equal parts of glucose and fructose. The tests were designed to control for side biases that were apparent in preliminary experiments. The mice preferred sucrose to fructose and glucose. Xylose, although the least preferred sugar, was willingly consumed by the rodents (up to 5.8 mL in 24 h). This contrasts with the strong rejection of xylose by nectarivorous birds on which similar preference tests were performed. The efficiency of xylose absorption and metabolism by A. namaquensis was investigated by measuring dietary intake, blood xylose levels, and urinary and fecal xylose output. Again in contrast to the birds, the apparent absorption efficiency of xylose was found to be very high at 97%, but exactly how the xylose is metabolized requires further study. Xylose is thought to be only slowly metabolized by mammals, and it is possible that intestinal bacteria may serve this purpose, like the ruminal bacteria that break down xylans in plant tissue.     

HEDONIC SCALES ARE A BETTER PREDICTOR THAN JUST-ABOUT-RIGHT SCALES OF OPTIMAL SWEETNESS IN LEMONADE1

A comparison of hedonic scales and just-about-right (JAR) scales is needed because data in previous studies using JAR scales suggest that predicted optimum levels of ingredients often are not the same as the levels in products that currently are sold successfully. Thus, in this research, consumers tested lemonade varying in sugar concentration from 6% to 14%, using (1) a JAR scale formed by boxes or a line and (2) a hedonic box-type scale. Predicted “optimum” levels of sweetness for the lemonade and differences in liking for the formulations were determined. The JAR line and box scales gave similar predicted optimal results (9.2% and 9.4% sucrose, respectively), which were significantly lower than the hedonic scale results (10.3% sucrose). In a preference test, consumers significantly preferred the 10.3% sugar lemonade over the 9.3% concentration, indicating that, based on paired preference testing, the hedonic scale resulted in better prediction of optimal sweetness than the JAR scale.     

Nectar sugar and amino acid preferences of Battus philenor (Lepidoptera, Papilionidae)

Abstract.

• 1 Butterflies of Battus philenor were tested for their preferences for nectar sugars and amino acids in an outdoor cage experiment.
• 2 The butterflies clearly preferred both sucrose and fructose over glucose. They also preferred sucrose over fructose.
• 3 No other preferences were found to be statistically significant, although male butterflies tended to prefer a plain sugar solution over a sugar solution containing a mixture of amino acids: females consumed both of these solutions in almost equal proportions.
• 4 The results are discussed with respect to nectar composition of butterfly pollinated flowers, flower preferences, physiological and reproductive aspects of butterflies.

     

Effects of substituted phenylethylamines on blowfly feeding behavior

The pharmacology of adult Phormia regina (Meigen) feeding behavior was explored by injecting candidate drugs into starved blowflies and then determining their responsiveness to aqueous sucrose, via the proboscis extension reflex. d-Amphetamine caused responsiveness to fall dramatically, while related drugs and biogenic amines had varying effects. When d-amphetamine-treated flies were fed 1 M sucrose, they consumed significantly more than control flies. Electrophysiological studies demonstrated that the responses of tarsal sugar receptor neurons to aqueous sucrose were not significantly altered by d-amphetamine. These observations are compatible with our hypothesis that octopamine positively modulates blowfly feeding behavior and suggest that other aromatic biogenic amines affect feeding behavior in this insect.     

Quantitative shotgun proteomics reveals extensive changes to the proteome of the orbitofrontal cortex in rats that are hyperactive following withdrawal from a high sugar diet

In most Westernized societies, there has been an alarming increase in the consumption of sugar‐sweetened drinks. For many adults these drinks represent a substantial proportion of their total daily caloric intake. Here we investigated whether extended exposure to sugar changes behavior and protein expression in the orbitofrontal cortex (OFC). Male adult Sprague‐Dawley rats (n = 8 per group) were treated for 26 days with either water or a 10% sucrose solution. Locomotor behavior was measured on the first and last day of treatment, then 1 week after treatment. Following the 1‐week period free from treatment, sucrose treated rats were significantly more active than the control. Two hours following final behavioral testing, brains were rapidly removed and prepared for proteomic analysis of the OFC. Label free quantitative shotgun proteomic analyses of three rats from each group found 290 proteins were differentially expressed in the sucrose treated group when compared to the control group. Major changes in the proteome were seen in proteins related to energy metabolism, mitochondrial function and the cellular response to stress. This research does not seek to suggest that sugar will cause specific neurological disorders, however similar changes in proteins have been seen in neurological disorders such as Alzheimer's disease, Parkinson's disease and schizophrenia.     

Intravenous administration of oxytocin in rats acutely decreases deprivation-induced chow intake,but it fails to affect consumption of palatable solutions

Despite its limited ability to cross the blood-brain barrier, peripherally administered oxytocin (OT) acutely decreases food intake, most likely via the brainstem and hypothalamic mechanisms. Studies performed to date have focused mainly on the effects of subcutaneous or intraperitoneal OT on the consumption of only solid calorie-dense diets (either standard or high-fat), whereas it is unknown whether, similarly to central OT, peripherally administered peptide reduces intake of calorie-dilute and non-caloric palatable solutions. In this project, we established that 0.1 μg/kg intravenous (IV) OT is the lowest anorexigenic dose, decreasing deprivation-induced standard chow intake by ca. 40% in rats and its effect does not stem from aversion. We then used this dose in paradigms in which effects of centrally acting OT ligands on consumption of palatable solutions had been previously reported. We found that IV OT did not change episodic intake of individually presented palatable solutions containing 10% sucrose, 0.1% saccharin, combined 10% sucrose-0.1% saccharin or 4.1%. Intralipid and it failed to affect daily scheduled consumption of a sucrose solution in non-deprived rats. In a two-bottle choice test, IV OT did not shift animals’ preference from sucrose to Intralipid. Finally, OT injected IV prior to the simultaneous presentation chow and a sucrose solution in food-deprived rats significantly decreased chow intake, whereas sugar water consumption remained unchanged. We conclude that IV OT reduces deprivation-induced chow intake without causing aversion, but the dose effective in decreasing energy-driven consumption of high-calorie food fails to affect consumption of palatable calorie-dilute solutions.     

Intersex and interspecies differences in sucrose consumption by rats with various behavioral strategies]

Sucrose consumption by male and female rats during active avoidance acquisition was measured in two rat strains: KLA (Koltushi low avoidance) and KHA (Koltushi high avoidance) selected for divergent performance in a shuttlebox. Under resting condition, there were no interstrain difference in sucrose consumption by males, but KHA females consumed significantly less sucrose than KLA females. Active avoidance acquisition during five consecutive days decreased sucrose consumption in KLA males and did not change sucrose consumption in KHA males. Within a week after exposure to the stress, the sucrose consumption by KLA males returned to its normal values, and KHA males consumed significantly more sucrose. The active avoidance conditioning did not affect sucrose consumption in females of both strains. Substitution of 32% solution for 4% produced on the first day a sharp decrease in sucrose consumption in males of both strains, while females sharply increased consumption of the diluted solution over the next four days of observation. During this time, males returned to consumption of the same volume of the solution despite its decreased concentration. The findings suggest that the exposure to the escapable stress induces the negative affect only in KLA males.