Suppression Of Sweetness Research Articles

Effects of the Cultivation Methods on the Sensory Quality and Phytochemical Profiles of Satsuma Mandarin (Citrus unshiu)

Citrus fruits have a distinctive flavor and can convey health benefits because of their unique phytochemicals. Phytochemical profiles are influenced by many factors, including variety and environmental growing conditions; however, the effect of the cultivation methods on the phytochemical profile of Satsuma mandarin (Citrus unshiu) has received little attention. In this study, we examined the relationships between the cultivation conditions, sensory quality, and phytochemical profiles of C. unshiu cultivated using four methods: open field, greenhouse, film mulching, and tunnel farming. The soil water content differed significantly between the cultivation methods and showed a strong positive correlation with sourness, bitterness, and astringency and a strong negative correlation with sweetness. The metabolites of C. unshiu were not associated with the soil water content but with the soil mineral content, including nitrogen (N+), phosphorus (P+), and potassium (K+). The soil P+ and K+ content was positively correlated with most secondary metabolites. The relative abundance of sugars did not differ significantly between the cultivation methods; however, the sweetness was higher under film mulching than under the other cultivation methods because of the suppression of sweetness by bitter compounds. We did not investigate the effect of other growing conditions, such as sunlight; however, the results improve our understanding of the effect of cultivation methods on the quality of C. unshiu and may inform crucial decisions concerning citrus cultivation.

Suppression of sweetness: evidence for central mechanism for suppression of sweetness from sucrose by citric acid.

The underlying mechanisms of taste interactions in humans are not well understood, and three mechanisms have been proposed, namely a chemical interaction, a peripheral physiological, and a central mechanism. In the present study, it was investigated which of these mechanisms causes the suppression of sweetness by citric acid. This was investigated using a split-tongue gustometer that can stimulate the two sides of the tongue with different stimuli simultaneously, enabling a comparison of sucrose and citric acid presented either separately on each side of the tongue simultaneously or in a mixture on one side. Two studies were conducted using low (Study 1; n = 50) and high (Study 2: n = 59) concentrations of sucrose (2.5% (w/w) and 10% (w/w), respectively), and citric acid (0.14% (w/w) and 0.18% (w/w), respectively). In neither of the studies was there a significant difference in sweetness intensity ratings between the two conditions where sucrose and citric acid were presented either separately or in a mixture form. However, both showed significantly lower sweetness ratings than without citric acid indicating suppression of the sweetness of sucrose from citric acid. This provides strong evidence for a central mechanism for the suppression of the sweetness of sucrose by citric acid. This mechanism seems to be equal in high and low concentrations of both sucrose and citric acid.

A Review on Phytochemical Investigation of Gymnema sylvestre Leaves

Gymnema sylvestre is a plant included in Apocynaceae family and is located in many regions of Asia, Africa and Australia. It is known to have blood glucose lowering potential and, thus, is widely used in traditional and Ayurvedic systems of medicine. A scrutiny of literature revealed some notable pharmacological activities of the plant such as antidiabetic, antiobesity, hypolipidaemic, antimicrobial, free radical scavenging and anti-inflammatory. The phytoconstituents responsible for sweet suppression activity includes triterpene saponins known as gymnemic acids, gymnemasaponins, and a polypeptide, gurmarin. Efforts have been made to prepare gudmar dried extract. These extracts were subjected for preliminary qualitative analysis, quantitative estimation of terpenoides, alkaloids and various other compounds. The present review is an attempt to highlight the phytochemical screening as well as its extraction process. Also chromatographic studies gave the presence of different compounds which can be used in creating monograph for this species.

Biohybrid Tongue for Evaluation of Taste Interaction between Sweetness and Sourness

The past decade has witnessed tremendous progress achieved in taste research, while few studies focus on interactions among taste compounds. Indeed, sweeteners and acidulants are commonly used food additives, and sweet-sour mixtures always provide improved tastes. For example, sensory studies have shown that sourness suppresses sweetness. However, the degree of sweetness suppression by sourness is difficult to evaluate quantitatively and objectively. Therefore, we propose a biohybrid tongue that is constructed by integrating mammalian gustatory epithelium with a microelectrode array chip. The taste quality and intensity information is coded in time-frequency patterns of local field potential. Different response patterns evoked by sweet and sour stimuli are observed, and the response is dose-dependent. Then, interaction effects of sourness against sweetness are quantified. The results indicate that suppression of sweetness by sourness occurs by increasing sourness concentrations. In summary, this study provides a powerful new tool for quantitative evaluation of sweet, sour, and their binary taste interactions that mimic the mammalian taste system.

Safety and efficacy of herbal tea for patients with diabetes mellitus

Purpose: The aim of this report is to review (i) safety and efficacy and (ii) medical marketing and regulation of Glucos Cut (GC) Tea. Methodology: The electronic databases such as PubMed, ScienceDirect, Google Scholar, and MEDLINE via EBSCOhost were searched with no limit to year of publication. Additional information was obtained from the Micromedex, “Medicines (Advertisement and Sales) Act 1956” and the “Guideline on Advertising of Medicines and Medicinal Products to General Public 2006.” Results: Of total 28 articles reviewed, only 20 relevant full-text articles were obtained and reviewed. GC Tea consists of five different herbs, i.e. green tea, Gymnema sylvestre, mulberry leaf, rooibos tea, and stevia. Green tea, mulberry leaf, and rooibos tea were reported to be effective at improving lipid profile and also exhibit a good antioxidant property. Review also found that G. sylvestre has a sweet suppression activity while stevia showed a significant reduction in postprandial glucose. All these five herbs were reported to have minimal adverse effect, which make it safe for human consumption. GC Tea is categorized as a drinking supplement, which is controlled by the Food Safety and Quality Division, Ministry of Health. Hence, it does not need to be registered with the National Pharmaceutical Control Bureau. Conclusion: GC Tea has benefits in reducing risk of diabetes, cardiovascular diseases, and obesity. GC Tea also has antioxidant properties that help reduce risk of cancer. Only mild adverse effects were reported when consuming these herbs in recommended dose.

Phytochemical and Pharmacological Properties ofGymnema sylvestre: An Important Medicinal Plant

Gymnema sylvestre (Asclepiadaceae), popularly known as “gurmar” for its distinct property as sugar destroyer, is a reputed herb in the Ayurvedic system of medicine. The phytoconstituents responsible for sweet suppression activity includes triterpene saponins known as gymnemic acids, gymnemasaponins, and a polypeptide, gurmarin. The herb exhibits a broad range of therapeutic effects as an effective natural remedy for diabetes, besides being used for arthritis, diuretic, anemia, osteoporosis, hypercholesterolemia, cardiopathy, asthma, constipation, microbial infections, indigestion, and anti-inflammatory. G. sylvestre has good prospects in the treatment of diabetes as it shows positive effects on blood sugar homeostasis, controls sugar cravings, and promotes regeneration of pancreas. The herbal extract is used in dietary supplements since it reduces body weight, blood cholesterol, and triglyceride levels and holds great prospects in dietary as well as pharmacological applications. This review explores the transition of a traditional therapeutic to a modern contemporary medication with an overview of phytochemistry and pharmacological activities of the herb and its phytoconstituents.

The Interactions of CO2, Ethanol, Hop Acids and Sweetener on Flavour Perception in a Model Beer

Beer is a complex beverage. Beer flavour is a multisensory experience in which, in addition to aroma volatiles, CO2, ethanol, bitterness (hop acids) and sweetness all contribute. To investigate the interactions between these fundamental components, a model beer system was developed using representative ingredients. Samples, selected according to a D-optimal design, were assessed by sensory profiling techniques by a trained panel. Predictive polynomial models generated from mean panel data described variations in the attributes as a function of design factors. Results show that CO2 significantly impacted on all discriminating attributes, including suppression of sweetness and modification of bitterness. A number of complex interactions with design factors showed the effects of CO2 to be dependent upon component concentration and level of carbonation. CO2 interacted with hop acids to increase carbonation and tingly perception, which increased linearly with hop acid addition but only at low levels of CO2. Ethanol was the main driver of warming perception and complexity. In agreement with other studies, ethanol enhanced sweet perception and also formed some complex interactions with hop acids and CO2 to modify various attributes, illustrating its ability to interact with both gustatory and trigeminal stimuli. Whether the mechanisms behind these interactions originate at the gustatory periphery or at higher centres in the brain is an area for further investigation. This study provides an in-depth assessment of important flavour components in beer and advances the limited data available on the effects of CO2 on sensory perception using a commonly carbonated beverage.

The sweet taste quality is linked to a cluster of taste fibers in primates: lactisole diminishes preference and responses to sweet in S fibers (sweet best) chorda tympani fibers of M. fascicularis monkey

BackgroundPsychophysically, sweet and bitter have long been considered separate taste qualities, evident already to the newborn human. The identification of different receptors for sweet and bitter located on separate cells of the taste buds substantiated this separation. However, this finding leads to the next question: is bitter and sweet also kept separated in the next link from the taste buds, the fibers of the taste nerves? Previous studies in non-human primates, P. troglodytes, C. aethiops, M. mulatta, M. fascicularis and C. jacchus, suggest that the sweet and bitter taste qualities are linked to specific groups of fibers called S and Q fibers. In this study we apply a new sweet taste modifier, lactisole, commercially available as a suppressor of the sweetness of sugars on the human tongue, to test our hypothesis that sweet taste is conveyed in S fibers.ResultsWe first ascertained that lactisole exerted similar suppression of sweetness in M. fascicularis, as reported in humans, by recording their preference of sweeteners and non- sweeteners with and without lactisole in two-bottle tests. The addition of lactisole significantly diminished the preference for all sweeteners but had no effect on the intake of non-sweet compounds or the intake of water. We then recorded the response to the same taste stimuli in 40 single chorda tympani nerve fibers. Comparison between single fiber nerve responses to stimuli with and without lactisole showed that lactisole only suppressed the responses to sweeteners in S fibers. It had no effect on the responses to any other stimuli in all other taste fibers.ConclusionIn M. fascicularis, lactisole diminishes the attractiveness of compounds, which taste sweet to humans. This behavior is linked to activity of fibers in the S-cluster. Assuming that lactisole blocks the T1R3 monomer of the sweet taste receptor T1R2/R3, these results present further support for the hypothesis that S fibers convey taste from T1R2/R3 receptors, while the impulse activity in non-S fibers originates from other kinds of receptors. The absence of the effect of lactisole on the faint responses in some S fibers to other stimuli as well as the responses to sweet and non-sweet stimuli in non-S fibers suggest that these responses originate from other taste receptors.

Revisiting Sugar-Fat Mixtures: Sweetness and Creaminess Vary with Phenotypic Markers of Oral Sensation

Genetic variation in oral sensation presumably influences ingestive behaviors through sensations arising from foods and beverages. Here, we investigated the influence of taste phenotype [6-n-propylthiouracil (PROP) bitterness, fungiform papillae (FP) density] on sweet and creamy sensations from sugar/fat mixtures. Seventy-nine subjects (43 males) reported the sweetness and creaminess of water or milk (skim, whole, heavy cream) varying in sucrose (0-20% w/v) on the general Labeled Magnitude Scale. Sweetness grew with sucrose concentration and when shifting from water to milk mixtures--the growth was greatest for those tasting PROP as most bitter. At higher sucrose levels, increasing fat blunted the PROP-sweet relationship, whereas at lower levels, the relationship was effectively eliminated. Perceived sweetness of the mixture exceeded that predicted from the sum of components at low sucrose concentrations (especially for those tasting PROP most bitter) but fell below predicted at high concentrations, irrespective of fat level. Creaminess increased greatly with fat level and somewhat with sucrose. Those tasting PROP most bitter perceived greater creaminess in the heavy cream across all sucrose levels. Perceived creaminess was somewhat lower than predicted, irrespective of PROP bitterness. The FP density generally showed similar effects as PROP on sweetness and creaminess, (but to a lesser degree) and revealed potential taste-somatosensory interactions in weakly sweet stimuli. These data support that taste phenotype affects the nature of enhancement or suppression of sweetness and creaminess in liquid fat/sugar mixtures. Taste phenotype effects on sweetness and creaminess likely involve differential taste, retronasal olfactory, and somatosensory contributions to these perceptual experiences.

Riboflavin-Binding Protein Exhibits Selective Sweet Suppression toward Protein Sweeteners

Riboflavin-binding protein (RBP) is well known as a riboflavin carrier protein in chicken egg and serum. A novel function of RBP was found as a sweet-suppressing protein. RBP, purified from hen egg white, suppressed the sweetness of protein sweeteners such as thaumatin, monellin, and lysozyme, whereas it did not suppress the sweetness of low molecular weight sweeteners such as sucrose, glycine, D-phenylalanine, saccharin, cyclamate, aspartame, and stevioside. Therefore, the sweet-suppressing activity of RBP was apparently selective to protein sweeteners. The sweet suppression by RBP was independent of binding of riboflavin with its molecule. Yolk RBP, with minor structural differences compared with egg white RBP, also elicited a weaker sweet suppression. However, other commercially available proteins including ovalbumin, ovomucoid, beta-lactogloblin, myoglobin, and albumin did not substantially alter the sweetness of protein sweeteners. Because a prerinse with RBP reduced the subsequent sweetness of protein sweeteners, whereas the enzymatic activity of lysozyme and the elution profile of lysozyme on gel permeation chromatography were not affected by RBP, it is suggested that the sweet suppression is caused by an interaction of RBP with a sweet taste receptor rather than with the protein sweeteners themselves. The selectivity in the sweet suppression by RBP is consistent with the existence of multiple interaction sites within a single sweet taste receptor.

Sweet–sour mixture suppression in older and young adults

Prior to investigating the effect of sweet–sour taste mixtures in neurologic dysphagia patients, this study examined whether older adults exhibited a similar pattern of sweet–sour mixture suppression compared with young adults. Two experiments were conducted comparing healthy older and young subjects, using sucrose or aspartame mixed with citric acid, with and without lemon flavoring. Two experiments examined the effect of sweetener type and level, citric acid level, flavoring, and cold temperature with the young only. Sourness was suppressed by sweeteners, and sweetness was suppressed by citric acid at suprathreshold tastant levels typically seen in beverages. There was little to no effect of flavoring or cold temperatures on the pattern of suppression of sweetness or sourness. The older group showed similar sweet–sour mixture suppression patterns to the young. The lack of flavoring or cold temperatures during videofluoroscopic swallow studies will not impact sweet–sour mixture suppression effects.

Influence of sweet suppressing agent on gustatory brain evoked potentials generated by taste stimuli.

A measurement system was employed to detect gustatory evoked potentials from human scalp by stimulus of a taste solution with the use of a laser beam device. The evoked potentials for four taste qualities (i.e., sweet-sucrose, salty-sodium chloride, sour-tartaric acid, and bitter-quinine-HCl) were measured before and after treatment with a sweet suppressing agent (i.e., gymnema sylvestre extract) to the tongue of a human. The solution was given to the chorda tympani nerve located 20 mm from the apex of the tongue and 15 mm from the left side of the center line. The maximum potential level and its latency were evaluated. Artificial saliva was used as a control solution. The evoked potentials obtained were averaged by eight evoked potentials to detect the peak of the evoked potential more clearly. The latencies for taste stimuli were found on two kinds of peaks at approximately 50 ms and 180 ms. These peaks are P1 and P2. The purpose of this study is to investigate the influence of sweet suppressing agent on P1 and P2. The influence of the sweet suppressing agent to evoked potential by salty, sour, and bitter taste stimuli was not recognized, but the responses to sweet (sucrose) were abolished after treatment with a sweet suppressing agent. It was recognized that the peak P2 originated from the taste stimulus. The peak P1 did not suffer the influence of the sweet suppression, so it was considered that the response to P1 was due to sensations other than the gustatory response, such as somatosense.

Interactions in caffeine–sucrose and coffee–sucrose mixtures: evidence of taste and flavor suppression

Taste-taste and flavor-taste interactions (suppression) in caffeine-sucrose and coffee-sucrose mixtures were determined. Similar interactions for both types of mixtures showed an extended hypoadditivity effect for overall taste or flavor intensity (percentage of suppression about 30-40%). Furthermore, mutual suppression among the components has been determined. Firstly, the physical intensity of the suppressive component controls the amount of suppression of the other component. Thus, the suppression of bitterness and coffee flavor qualities increase when sucrose levels increase, and similarly, the suppression of sweetness increases when caffeine or coffee levels rise. Secondly, the magnitude of suppression depends upon the quality of the suppressive component. Comparisons of the reciprocal actions were made at similar subjective intensities of the mixture's constituents in isolation. The results showed that, at similar perceived intensities, caffeine bitterness or coffee flavor were suppressed by sucrose but sweetness was not affected by caffeine or coffee.