Bitter sensory studies

A sensory study based on an incomplete factorial design allowed to demonstrate that astringency of procyanidins was reduced in the presence of rhamnogalaturonan II added at levels encountered in wine but was modified neither by anthocyanins nor by the other wine polysaccharides (mannoproteins and arabinogalactan proteins). Increase in ethanol level resulted in higher bitterness perception but had no effect on astringency. 

Comparative sensory studies on the role of alapyridaine in modifying bitter and sour taste perception revealed that neither the threshold concentrations of the bitter compounds L-phenylalanine and caffeine, nor that of the sour tasting citric acid were influenced by the presence of alapyridaine 13). 

A recent sensory study of taste modification demonstrated that flavanones of yerba Santa (eriodictyol, homoeriodictyol, and sterubin) had a significant masking effect on the bitter taste of caffeine and other bitter compounds, such as salicin, paracetamol, and quinine. The sodium salt of homoeriodictyol had a dose-dependent bitter masking effect against caffeine and amarogentin. ... 

Assessment of taste is achieved by sensory analysis, from very simple experiments such as triangular tests aiming at determining detection thresholds to complex descriptive analysis approaches. A method referred to as time-intensity that consists in recording continuously the intensity of a given sensation over time under standardized conditions has been applied to study flavonoid bitterness and astringency properties. 

Reviews of taste sensations normally concentrate on four basic tastes - sweet, salty, sour and bitter (7,2) however, other oral sensations can contribute important information to the perceived flavor (3), Examples of stimulants evoking these very different sensory sensations are shown in TABLE I. Studies on the mechaiusms of perception are usually restricted to sensation-specific stimuli however, food flavors represent an interaction among the various sensations. This chapter describes recent... 

Sweetness Production by the Combination of Bitter and Sweet Tastes. Sensory tests using typically bitter compounds such as brucine, strychnine, phenylfiiiourea, caffeine and bitter peptides were performed. Sensory tests using typically bitter compounds such as brucine, strychnine, phenylthiourea, caffeine and bitter peptides were performed. Sensory taste impression were also measured for combinations of acetic acid (sour) and typical bitter compounds (5). The data from these studies indicated that the tastes of ese bitter/sour mixtures changed to a sweet taste regardless of their chemical structure of the bitter component (Table II). 

In the first part of the twentieth century, reports appeared on differences among Whites, Blacks, and Chinese in response to drugs and chemicals. During the 1920s and 1930s, individual differences in sensory perception of chemicals were studied. Human family studies showed that the failure to perceive bitterness after tasting phenyl-thiourea was transmitted from parents to... 

Taste of amino acids was studied using the taste sensor [23]. Taste of amino acids has had the large attention so far because each of them elicits complicated mixed taste itself, e.g., L-valine produces sweet and bitter tastes at the same time. Thus, there exist detailed data on taste intensity and taste quality of various amino acids by sensory panel tests [26]. The response of the sensor to amino acids was compared with the results of the panel tests, and response potentials from the eight membranes were transformed into five basic tastes by multiple linear regression. This expression of five basic tastes reproduced human taste sensation very well. 

Quinine also has pharmacological activity as an antimalarial, and some studies have been made in order to find a method to diminish or suppress its bitter taste. This can be achieved by adding sweet compounds such as sucrose or aspartame or nonspecific bitter taste inhibitors such as NaCl or phosphatidic add and tannic add [39]. The effects have been studied by sensory evaluation tests in human volunteers, a binding... 

In cheese, a matrix effect could modulate salty and bitter perception in different ways and evolve during the maturation process. The composition of the matrix and physiological parameters had to be taken into account to better understand temporal release and perception of flavor. The study of the relationships between sensory and aroma release gave reliable results only for sulfury note which was the most intense and due to well identified and specific compoimds. 

In taste studies, sucrose is usually taken as a reference standard in the sensory evaluation of sweetness and caffeine is generally used as the reference material for bitterness. However, sour and salty tastants modulate taste-receptor function by direct effect on specific ion channels in the membrane, while sweet and bitter tasting compounds seem to bind to closely located receptors which are coupled to a guanidine-nucleotide binding protein (G-protein). The perception of their tastes proceeds through a transduction mechanism involving G-protein and a second messenger system (Kinnamon, 1988). 

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