Sensory consistency

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. 

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. 

Reverse Osmosis. A reverse osmosis (RO) process has been developed to remove alcohol from distilled spirits without affecting the sensory properties (14). It consists of passing barrel-strength whiskey through a permeable membrane at high pressure, causing the alcohol to permeate the membrane and concentrating the flavor components in the retentate. 

The human brain is comprised of many millions of interconnected units, known individually as biological neurons. Each neuron consists of a cell to which is attached several dendrites (inputs) and a single axon (output). The axon connects to many other neurons via connection points called synapses. A synapse produces a chemical reaction in response to an input. The biological neuron fires if the sum of the synaptic reactions is sufficiently large. The brain is a complex network of sensory and motor neurons that provide a human being with the capacity to remember, think, learn and reason. 

The neurons from which NTs are released number more than 7 billion in the human brain. Each (Fig. 1.2) consists of a cell body, the soma or perikaryon, with one major cytoplasmic process termed the axon, which projects variable distances to other neurons, e.g. from a cortical pyramidal cell to adjacent cortical neurons, or to striatal neurons or to spinal cord motoneurons. Thus by giving off a number of branches from its axon one neuron can influence a number of others. All neurons, except primary sensory neurons with cell bodies in the spinal dorsal root ganglia, have a number of other, generally shorter, projections running much shorter distances among neighbouring neurons like the branches of a tree. These processes are the dendrites. Their... 

Many different types of sensory receptors are located throughout the body. These receptors monitor the status of the internal environment or that of the surroundings. Sensory receptors are sensitive to specific types of stimuli and measure the value of a physiological variable. For example, arterial baroreceptors measure blood pressure and chemoreceptors measure the oxygen and carbon dioxide content of the blood. The information detected by these sensors then travels by way of afferent neuronal pathways to the central nervous system (CNS). The CNS is the integrative portion of the nervous system and consists of the (1) brain and the (2) spinal cord. 

The afferent division carries sensory information toward the CNS and the efferent division carries motor information away from the CNS toward the effector tissues (muscles and glands). The efferent division is further divided into two components (1) the somatic nervous system, which consists of motor neurons that innervate skeletal muscle and (2) the autonomic nervous system that innervates cardiac muscle, smooth muscle, and glands. 

The brain is the integrative portion of the nervous system that serves to receive, process, and store sensory information and then plan and orchestrate the appropriate motor response. It is divided into several anatomically and functionally distinct regions (see Table 6.2). The forebrain consists of the cerebrum, basal ganglia, thalamus, and hypothalamus. The midbrain, along with the pons and the medulla of the hindbrain, composes the functional region referred to as the brainstem. The cerebellum is also considered a component of the hindbrain but is functionally distinct from the brainstem. 

The functional region known as the brainstem consists of the midbrain, and the pons and medulla of the hindbrain. It is continuous with the spinal cord and serves as an important connection between the brain and spinal cord because all sensory and motor pathways pass through it. The brainstem consists of numerous neuronal clusters or centers, each of which controls vital, life-supporting processes. 

Milk from cows affected with mastitis alters the sensory quality of raw milk and cheese (Munro el al., 1984). Sensory defects are reported as increased rancidity and bitterness, factors which are consistent with higher levels of lipolysis and proteolysis (Ma et al., 2000). 

The difference in sensory quality between females and castrated males is not consistent over several studies. Enfalt et al. (1997) and Jonsall et al. (2001) found that loins from castrated males scored higher for tenderness and juiciness than loins from females. In contrast, Jonsall et al. (2000) found no sensory effect of sex on loins and the same working group detected in a further investigation that loin from gilts scored higher for juiciness and lower for off-flavour than loin from castrated males. Obviously, the effect of sex on sensorial quality is of minor relevance and can be overruled by other effects. 

Nevertheless, there is good evidence that in all purely bluelight sensitive organisms, the photoreceptor is a flavin (flavoprotein) (Table 2), which appears to be bound to membranes (plasmalemma) in a highly dichroic manner. The mechanism of sensory transduction is probably correlated with light-induced redox reactions mediated by a flavin. This observation is consistent with the fact that nearly all physiolog-... 

Among the many sensory reactions Phycomyces displays, the study of the photoreceptor and adaptation deserves maximal attention, since Phycomyces shares these two attributes with a variety of other blue light sensitive organisms. Action-spectroscopy indicates a flavin as the photoreceptor of Phycomyces. /3-carotene was positively ruled out as a possible receptor, since mutants with no trace amounts of )3-carotene are phototropical normal. The photoreceptor has not yet been isolated. As in other systems the difficulty consists in distinguishing the flavin photoreceptor from the bulk flavoproteins in the cell. One therefore needs unambiguous criteria for the identification of the photoreceptor. The most promising approach for an isolation would be a photoreceptor mutant and we described the properties those mutants should have. Until now there is no firm evidence that the photomutants, madA or madB are defective in the photoreceptor. 

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