Taste-active components

Take et al. (38) who surveyed the taste-active components of the snow crab, Chionoecetes opilio, in the same way as described for the shrimp and prawn in the preceding section, found that the amino acids were the most important flavor components, and that a synthetic extract (Table VI) prepared by simulating the crab extract reproduced its taste fairly well. 

Fuke, S. and Konosu, S., Taste-active components in some foods A review of Japanese research. Physiol. Behav., 49, 863-868,1991. 

Fuke, S., Taste-active components of seafoods with special reference to umami substances, in Seafoods Chemistry, Processing, Technology and Quality, Shahidi, F. and Botta, J.R., Eds., Blackie Academic and Professional, Glasgow, United Kingdom, 1994, pp. 115-139. 

Heterocyclic compounds are those in which one or more carbon atoms in the ring are replaced by another element, which is called a heteroatom. Most common in foods are five-membered and six-membered heterocyclic compounds containing as the heteroatom oxygen, sulfur or nitrogen. Also common are heterocycles containing more of the same or different heteroatoms. Heterocyclic compounds are important odour- and taste-active components of many foods. The basic structures of most oxygen, sulfur and nitrogen heterocycles are shown in formulae 8-157. More important than these basic heterocycles, however, are their... 

The flavor of fish and seafoods is composed of taste-active low molecular-weight extractives and aroma-active compounds. The taste-active compoimds are more abundant in the tissues of mollusks and crustaceans than fish. The most important non-volatile taste components are fi-ee amino acids, nucleotides, inorganic salts and quaternary ammonia bases. Alcohols, aldehydes, ketones, furans, nitrogen-containing compounds, sulfur-containing compounds, hydrocarbons, esters and phenols are the most important volatiles is shellfish. Alkyl pyrazines and sulfur-containing compounds are important contributors to the cooked aroma of crustaceans. Furans pyrazines, and Lactones have been found in heat-treated seafoods. Dimethyl disulfide, dimethyl trisulfide, heterocyclic sulfiir-containing compounds (alkylthiophenes) have been found in most thermally treated crustaceans like prawn, crab, oyster, crayfish and shrimp (52). 

Japan Tobacco and Salt Public Corporation Tobacco taste and flavor improving agent containing 2,3 -dipyridyl as active component Japanese Patent J56045183, April 24, 1981. 

The detailed overview on the nutritional composition and health promoting components of hazelnut provided in this chapter summarizes the existing knowledge and appreciation for the use of hazelnut and its products in a variety of food and specialty products. Besides nutritional value and health aspects, the presence of taste- and aroma-active components contribute to the sensory characteristics of products. Thus, better taste and aroma/flavor of hazelnut may increase the consumption of this nutritionally important nut, as discussed in this chapter. In addition, characteristics of raw (natural) hazelnut as well as its health promotion and disease prevention aspects are given in detail. Aroma-active components of roasted hazelnut are also discussed. 

Microencapsulated solid preparations are widely used in pharmaceutical, chemical, and other industries to protect various substances from environmental impact, as well as for extending their action [137], In the pharmaceutical field, in particular, these preparations are mainly used to get controlled release drug kinetics, to minimize side effects, to reduce gastric irritations, and to mask the unpleasant taste of the contained drug [137-142]. Indeed, many different active components are microencapsulated analgesics, antibiotics, antihistamine, cardiovascular agents, iron salts, antipsychot-ics [143], vitamins, peptides [144], proteins [145], antiasthma [140,146], broncodilators, diuretics, anticancerogens, tranquilizers, and antihypertensives [137],... 

The active component of willow bark was found to be salicin, a compound composed of salicyl alcohol joined to a unit of j3-D-glucose (Section 17.2). Hydrolysis of salicin in aqueous acid gives salicyl alcohol, which can then be oxidized to salicylic acid, an even more effective reliever of pain, fever, and inflammation than salicin and one without its extremely bitter taste ... 

Acetic acid is found in most people s homes as the active component of vinegar. It is also produced in improperly stored wines. The word vinegar originates from the French vin aigre, which means "sour wine." The presence of vinegar in wines is considered a serious fault, making the wine taste like salad dressing. 

Bases are less common in foods than acids because of their bitter taste. A Sour Patch Kid coated with a base would never sell. Our aversion to the taste of bases is probably an adaptation to protect us against alkaloids, organic bases foimd in plants (see the Chemistry and Health box in Section 14.9). Alkaloids are often poisonous—the active component of hemlock, for example, is the alkaloid coniine—and their bitter taste warns us against eating tirem. Nonetheless, some foods, such as coffee, contain small amounts of base (caffeine is a base). Many people enjoy the bitterness, but only after acquiring the taste over time. 

Besides nutrients, foods contain many substances that influence the food sensory impression and its organoleptic properties. These food constituents are known as sensoriaUy active compounds. They determine the sensory value (quality) of foods, inducing an olfactory sensation (perception), which is described as the aroma, odour and smell, gustative perception, which is the taste, visual perception, which is the colour, haptic (tactile) perception, which is the touch and feel, and auditorial perception, which is the sound. The olfactory sensation is derived from odour-active compounds and the gustative perception from taste-active compounds. Flavour is the sensory impression determined by the chemical senses of both taste and smell and is caused by flavour-active food components. Haptic sensation is the texture, which is affected mainly by high molecular weight compounds, such as proteins and polysaccharides, often referred to collectively as hydrocoUoids. Geometric aspects of texture that evoke both haptic and visual sensations symbolise the terms appearance and shape. 

Volatile aldehydes and ketones are the most important odour-and taste-active substances. They occur in foods as primary substances, as components of various essential oils and also result from enzymatic and chemical reactions from various precursors as secondary substances. They are often desirable flavour-active components of foods, but in some cases may also carry undesirable odour and taste. Then they serve as indicators of unwanted changes in sensory or nutritional value of foods (such as autoxidation of lipids). 

Aliphatic dicarboxylic and tricarboxylic acids are non-volatile compounds and may therefore just have a role as taste-active (acidic) food components. 

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