Quantitative Sensory Assessment

Industry has standardized procedures for the quantitative sensory assessment of the perceived olfactory intensity of indoor malodors and their relationship to the deodorant efficacy of air freshener products. Synthetic malodors are used for these evaluation purposes. These malodors should be hedonicaHy associated to the "real" malodor, and must be readily available and of consistent odor quaUty. These malodors should be tested in various concentrations and be representative of intensities experienced under normal domestic conditions. 

The third and fourth influential factors on wine aroma chemistry arise from the problems caused by the matrix on both the isolation and preconcentration of molecules and on the sensory assessment of the role played by the impact odorants. The presence of major volatiles, such as ethanol and fusel alcohols, complicates the isolation of the other wine odorants, particularly of those present at low levels. This has a marked influence on the way in which the extracts for screening and for further qualitative or quantitative studies should be prepared. On the other hand, ethanol and the major fermentation volatiles have also a deep influence on the way in which the odor chemicals are released and perceived. 

Two types of sensory assessment are used for ice cream, analytical methods, in which trained tasters provide quantitative sensory data, and consumer testing, in which consumers are asked questions such as how much they like a product and whether they would be likely to buy it. 

Many tests have been devised to provide quantitative measures of behavioral disturbances caused by neurotoxic chemicals. Tests have been devised that assess the effects of chemicals on four behavioral functions (D Mello 1992). These are sensory, cognitive, motor, and affective functions. However, because the entire nervous system tends to work in an integrated way, these functions are not easily separable from one another. For example, the outcome of tests focused on sensory perception by rats may be influenced by effects of the test chemical on motor function. 

We have seen that in the short term, the changes in skin due to cleansing primarily manifest as changes in sensory perception. Consumer perception methods are the primary means of assessing the transient onset of tightness and itch. Naive panels can provide comparative data among several cleansers tested but can not provide consistent quantitative measure of performance. Expert panels... 

In conclusion, the study of the wine aroma chemicals and the understanding of the role they play in the different wine aroma nuances have to be structured into a numbers of steps strongly constrained by the previous considerations. Such steps will be the subject of thischapter. The first step is about the screening of aroma molecules, which will be carried out by using gas chromatography-olfactometry. The second will be the isolation and identification of odorants. The third is the quantitative determination, for which only a very brief outline will be given, and the fourth is about the sensory tools used to assess the sensory role played by the different odorants. 

Quantitative somatosensory testing (QST) uses calibrated tools to assess the function of all the sensory modalities. The smaller caliber nerves are evaluated by measuring pain and temperature (hot and cold) thresholds, and larger caliber nerves are evaluated by measuring the thresholds for perception of vibration, joint position, and touch. This is done by touching the patients skin with stimuli of defined characteristics, such as a computer-controlled probe that can heat or cool to specific temperatures. The effectiveness of QST is limited because it requires subject cooperation and is inherently subjective, as it relies on the reported interpretation of sensory stimulation from the subject. This also influences reproducibility of this sensory test (Fink and Qaklander, 2006). 

Some quantitative, instrumental methods exist for assessing fabric softness, but they are not sensitive enough to assess differences between softeners. The evaluation is usually carried out by sensory perception. The feeling of a textile is very subjective as, besides the basic physical properties of the fabrics on which it depends, it is also influenced by many evaluator-linked unquantifiable parameters such as mood and tactile sensitivity [52],... 

Quantitative descriptive analysis (QDA ) is a method that is often used. A panel of tasters first assesses a set of training samples and scores the intensity of a number of sensory characteristics (attributes) of the samples. There are many different attributes, and there is no unique, exhaustive list, but some that are commonly used to describe the texture... 

Jones, R.D., Sharman, N.B., Watson, R.W., and Muir, S.R. 1993. A PC-based battery of tests for quantitative assessment of upper-limb sensory-motor function in brain disorders. Proc. Ann. Int. Conf. IEEE Eng. Med. Biol. Soc. 15 1414—1415. 

Based on Fig. 21.1, we decided to quantitatively assess the sensory consumer journey at seven different touch points ... 

Sensory examination should include touch, pinprick, pressure, cold, heat, and vibration assessment [5j. Responses are graded as normal, decreased, or increased to determine whether negative or positive sensory phenomena are involved. The stimulus-evoked (positive) pain types are classified as dysesthetic, hyper-algesic, or allodynic, and according to the dynamic or static character of the. stimulus [6,7]. A m ore sophisticated neurophysiological test is the quantitative... 

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