Basic-tastes test

Basic taste Test standard CAS Registry Number Wt % in water... 

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. 

A taste map is proposed for expressing the taste quality of beer [28]. This map is based on sensory tests made by humans, and is composed of the abscissa expressing "rich taste" or "soft taste" and the ordinate expressing "sharp touch" or "smooth touch". These expressions cannot be replaced by the terms of the five basic taste qualities. The rich or soft taste may be mainly related to the concentration of wheat, whereas the sharp or smooth touch may arise from the concentrations of alcohol, hops and so on. We tried to express... 

The direct transformation from the output pattern to the taste quality was performed here as one trial of expressing the actual human sensation using the output electrical pattern. A similar trial was done for evaluation of the strengths of sourness and saltiness, which will be mentioned later. These two trials depend on the utilization of simple transformation equations by extracting typical properties of output patterns. This method is effective if some data on sensory tests, using humans as a standard, can be obtained to compare with the sensor outputs. However, the expressions for the tastes of beer are obscure because they are not described by the five basic taste qualities. The purpose of the application of the taste sensor is also to express these kinds of obscure terms of human sense in scientific terms. 

We tried three methods to quantify the taste of the foodstuffs. The first method is to compare output patterns between test solution and the mixed solutions by performing many measurements of various mixed solutions (Figure 10) [22], The taste of commercial aqueous drink was reproduced by blending four basic taste substances (HC1, NaCl, quinine, sucrose) so that the response pattern could get closest to that of an aqueous drink. With this attempt, the best combination of the concentrations of basic taste substances was obtained 2 mM HC1, 50 mM NaCl, 0.2 mM quinine and 100 mM sucrose. This mixed solution produced almost the same taste as the aqueous drink. 

Moskowitz and Arabic (1970) found that the taste intensity (sweetness, sourness, saltiness, and bitterness) was related to the apparent viscosity of carboxymethylcel-lulose solutions by a power function with a negative slope. Pangbom et al. (1973) observed that the influence of different hydrocolloids on the perception of some basic taste intensities (saltiness, bitterness, sourness) appeared to be more dependent on the nature of the hydrocolloid and the taste of the substance than on the viscosity level. In contrast, sweetness imparted by sucrose was found to be highly dependent on viscosity, that is, the hydrocolloid concentration above a certain viscosity threshold, it was shown that the sweetness intensity of sucrose was significantly depressed. Saltiness was the taste attribute less affected, sourness, imparted by citric acid, was significantly reduced by all hydrocolloids tested, and for the other taste substances, the presence of a hydrocolloid generally enhanced the taste intensity of saccharin and depressed that of sucrose and caffeine (bitterness). 

The next step is to screen panelists for their sensory acuity. This is done by having panelists complete tests designed to identify their ability to recognize basic tastes, common odors, and textural characteristics. More information on these tests is provided in guidelines published by ASTM (13). 

An electronic tongue based on dnal shear horizontal surface acoustic wave (SH-SAW) devices was developed to discriminate between the basic tastes of sour, salt, bitter, and sweet [57]. Sixty MHz SH-SAW delay line sensors were fabricated and placed below a miniature PTFE housing containing the test liquid. All the tastes were correctly classified without the need for a selective biological or chemical coating. 

A commercially interesting low calorie fat has been produced from sucrose. Proctor Gamble has patented a mixture of penta- to octafatty acid ester derivatives of sucrose under the brand name Olestra. It was approved by the FDA in January 1996 for use as up to 100% replacement for the oil used in preparing savory snacks and biscuits. Olestra, a viscous, bland-tasting Hquid insoluble in water, has an appearance and color similar to refined edible vegetable oils. It is basically inert from a toxicity point of view as it is not metabolized or absorbed. It absorbs cholesterol (low density Hpoprotein) and removes certain fat-soluble vitamins (A, D, E, and K). Hence, Olestra has to be supplemented with these vitamins. No standard LD q tests have been performed on Olestra however, several chronic and subchronic studies were performed at levels of 15% in the diet, and no evidence of toxicity was found. No threshold limit value (TLV), expressed as a maximum exposure per m of air, has been estabhshed, but it is estimated to be similar to that of an inert hpid material at 5 mg/m. ... 

Our studies of the absorption, permeation, and extraction properties of containers produced from high nitrile barrier resins have demonstrated that they meet or surpass the basic criteria established for retention of taste and odor characteristics of carbonated soft drinks. Sensory tests, which can isolate and identify end results as well as integrate collective effects, have confirmed this judgement and have established the general compatibility of these containers with a variety of beverage products from a taste and odor standpoint. Furthermore, these materials have the excellent physical properties required for containers which will find wide use in food and beverage packaging. 

The compounds best known for their bitter taste belong to the alkaloids and glycosides. Alkaloids are basic nitrogen-containing organic compounds that are derived from pyridine, pyrrolidine, quinoline, isoquinoline, or purine. Quinine is often used as a standard for testing bitterness (Figure 7-13). 

Experiment 52. — Dissolve a small piece of sodium hydroxide in an evaporating dish half full of water. Slowly add dilute hydrochloric acid, until a drop taken from the dish by means of a glass rod reddens blue litmus paper. Then evaporate to dryness by heating over a piece of wire gauze. Since the residue mechanically holds traces of the excess of hydrochloric acid added, it is necessary to remove this acid before applying any test. Heat the dish until all the yellow color disappears, then moisten the residue carefully with a few drops of warm water and heat again to remove the last traces of acid. This precaution is essential to the success of the experiment. Test a portion of the residue with litmus paper to find whether it has acid, basic, or neutral properties. Taste a little. Test (a) a solution of the residue for a chloride, and (b) a portion of the solid residue for sodium. Draw a definite conclusion from the total evidence. 

Aqueous solutions of bases taste bitter. You may have noticed this fact if you have ever gotten soap, a basic substance, in your mouth. As with acids, taste should NEVER be used to test a substance to see if it is a base. Many bases are caustic they attack the skin and tissues, causing severe bums. 

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