Sensations

This compound is a lachrymator and also produces a burning sensation on the skill i the latter is relieved by washing the affecte[Pg.695]

Perhaps the most sensational synthesis of chiysanthemic add uses this strategy. You ma r remember that TM 31 is usually made from the adduct of acetylene and acetone. Draw out the stages of this reaction sequence. 

Generally, aerosol packaging consists of many dehcately balanced variables. Even hardware design plays an important part. For example, valves that produce considerable breakup are used for the warm sensation desired in some personal products. 

Effective temperature (ET ) is a single number representing those combinations of temperature and humidity which are equivalent in terms of comfort. It is defined as the dry-bulb temperature of the environment at 50% relative humidity. Standard effective temperature loci for normally clothed, sedentary persons are plotted on Eigure 3. The sensation of comfort depends in part upon the wetness of one s skin. Thus, as a person becomes more active the effective temperature lines become more hori2ontal and the influence of relative humidity is more pronounced. 

Sensory perception is both quaUtative and quantitative. The taste of sucrose and the smell of linalool are two different kinds of sensory perceptions and each of these sensations can have different intensities. Sweet, bitter, salty, fmity, floral, etc, are different flavor quaUties produced by different chemical compounds the intensity of a particular sensory quaUty is deterrnined by the amount of the stimulus present. The saltiness of a sodium chloride solution becomes more intense if more of the salt is added, but its quaUty does not change. However, if hydrochloric acid is substituted for sodium chloride, the flavor quahty is sour not salty. For this reason, quaUty is substitutive, and quantity, intensity, or magnitude is additive (13). The sensory properties of food are generally compHcated, consisting of many different flavor quaUties at different intensities. The first task of sensory analysis is to identify the component quahties and then to determine their various intensities. 

Several aspects affect the extent and character of taste and smell. People differ considerably in sensitivity and appreciation of smell and taste, and there is lack of a common language to describe smell and taste experiences. A hereditary or genetic factor may cause a variation between individual reactions, eg, phenylthiourea causes a bitter taste sensation which may not be perceptible to certain people whose general abiUty to distinguish other tastes is not noticeably impaired (17). The variation of pH in saUva, which acts as a buffer and the charge carrier for the depolarization of the taste cell, may influence the perception of acidity differently in people (15,18). Enzymes in saUva can cause rapid chemical changes in basic food ingredients, such as proteins and carbohydrates, with variable effects on the individual. 

Simultaneous stimulation of the tongue with the appHcation of different taste stimuli produces an interaction, modification, or blending of the stimuli in some instances but not in others. Warm and cold sensations are reported to act similarly on the tongue in two groups bitter, warm, and sweet and sour, cold, and salty (24). The theory of the specificity of the taste buds may be subject to modification (25). 

Whatever the physiology of odor perception may be, the sense of smell is keener than that of taste (22). If flavors are classed into odors and tastes as is common practice in science, it can be calculated that there are probably more than 10 possible sensations of odor and only a few, perhaps five, sensations of taste (13,21,35—37). Just as a hereditary or genetic factor may cause taste variations between individuals toward phenylthiourea, a similar factor may be in operation with odor. The odor of the steroid androsterone, found in many foods and human sweat, may eflcit different responses from different individuals. Some are very sensitive to it and find it unpleasant. To others, who are less sensitive to it, it has a musk or sandalwood-like smell. Approximately 50% of the adults tested cannot detect any odor even at extremely high concentrations. It is befleved that this abiUty is genetically determined (38). 

Jignosia. InabiUty to recognize sensations may be primarily in one sense, eg, olfactory agnosia. 

Cloying A taste sensation that stimulates beyond the point of satiation frequently used to describe overly sweet products. 

Flavor. The sensation produced by a material taken into the mouth, perceived principally by the senses of taste and smell, but also by the common chemical sense produced by pain, tactile, and temperature receptors in the mouth. 

Odor and Odorant. That which is smelled. Odor may refer to the odorant or to the sensation resulting from the stimulation of olfactory receptors in the nasal cavity by gaseous material. 

Penicillamine (29) can be effective in patients with refractory RA and may delay progression of erosions, but adverse effects limit its useflilness. The most common adverse side effects for penicillamine are similar to those of parenteral gold therapy, ie, pmritic rash, protein uria, leukopenia, and thrombocytopenia. Decreased or altered taste sensation is a relatively common adverse effect for penicillamine. A monthly blood count, platelet count, and urinalysis are recommended, and also hepatic and renal function should be periodically monitored. Penicillamine is teratogenic and should not be used during pregnancy. 

Opiates are useful analgesics because they reduce pain sensation without blocking feeling or other sensations. However, they also affect mood, iaduce euphoria, reduce mental acuity, and iaduce physical dependence. They can be immunosuppressive and dismpt other homeostatic processes through... 

Masking. Masking can be defined as the reduction of olfactory perception of a defined odor stimulus by means of presentation of another odorous substance without the physical removal or chemical alteration of the defined stimulus from the environment. Masking is therefore hyperadditive it raises the total odor level, possibly creating an overpowering sensation, and maybe defined as a reodorant, rather than a deodorant. Its end result can be explained by the simple equation of 1 + 1 = >2 (Fig. 2a). 

A SAPP with intermediate reactivity is used in combination with fast-acting MCP for the manufacturer of industrial baking powder and for retail and wholesale prepared cake mixes. SAPP imparts a bitter aftertaste which is often characterized as a mild burning sensation, especially when used in a product of low sweetness. SAPP is normally used at an NV of 72. However, it may be used at slightly higher or lower NV to obtain specific effects in certain types of baked goods. 

Liquid bromine produces a mild cooling sensation on first contact with the skin. This is followed by a sensation of heat. If bromine is not removed immediately by flooding with water, the skin becomes red and finally brown, resulting in a deep bum that heals slowly. Contact with concentrated vapor can also cause bums and bflsters. Eor very small areas of contact in the laboratory, a 10% solution of sodium thiosulfate in water can neutralize bromine and such a solution should be available when working with bromine. Bromine is especially hazardous to the tissues of the eyes where severely painfiil and destmctive bums may result from contact with either Hquid or concentrated vapor. Ingestion causes severe bums to the gastrointestinal tract (62,63). 

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