Single flavor components

Dilution The dilution indicates the smallest amount of test material that can be detected. By preparing a dilution of an aqueous extract (food substance or chemical mixture) the single flavor component can be analyzed. 

The complexity of food flavor precursors is manifested by the number of compounds estimated in each class of compounds and by the possible total number in a single raw food. The possible number of flavor components produced per one compound of flavor precursor is estimated in the range 10-150, but is reduced to 5-40 to eliminate compounds that might be produced... 

One of the classic examples of this type of response is the case of the cyclic ketone carvone, which contains a single stereocenter ( ).The S enantiomer is the principal odor and flavor component in caraway seed, whereas the R enantiomer gives rise to the odor and flavor of spearmint ... 

Since early antiquity, spices and resins from animal and plant sources have been used extensively for perfumery and flavor purposes, and to a lesser extent for their observed or presumed preservative properties. Fragrance and flavor materials vary from highly complex mixtures to single chemicals. Their history began when people discovered that components characteristic of the aroma of natural products could be enriched by simple methods. Recipes for extraction with olive oil and for distillation have survived from pre-Christian times to this day. 

The odors of single chemical compounds are extremely difficult to describe unequivocally. The odors of complex mixtures are often impossible to describe unless one of the components is so characteristic that it largely determines the odor or flavor of the composition. Although an objective classification is not possible, an odor can be described by adjectives such as flowery, fruity, woody, or hay-like, which relate the fragrances to natural or other known products with similar odors. 

Licorice is one of the most widely investigated plant products. Modern chemistry has allowed for the isolation, separation, and characterization of dozens of different compounds found in the root extract. No single component accounts for licorice s distinctive flavor, but anethole comes close. This compound occurs in the anise plant, from which it can be extracted, or it can be synthesized in the laboratory. Candy makers commonly use anethole to impart a licorice flavor to their products, like that black stringy confection. This is why naming the treat licorice is misleading. Even when it is made with real licorice extract, the concentration of licorice compounds is very low. We should be aware of this, because it means that neither the problems nor the potential therapeutic effects that we attribute to real licorice apply to the twists we chew on in movie theaters. Real licorice twists do exist, though — mostly in Europe. 

During AEDA, interactions between the odorants are not taken into consideration, since every odorant is evaluated individually. Therefore, it may be possible that odorants are recognized which are possibly masked in the food flavor by more potent odorants. Furthermore, the odor activity values only partially reflect the situation in the food, since OAVs are mostly calculated on the basis of odor thresholds of single odorants in pure solvents. However, in the food system, the threshold values may be influenced by nonvolatile components such as lipids, sugars or proteins. The following examples will indicate that systematic sensory model studies are important further steps in evaluating the contribution of single odorants to the overall food aroma. 

In 1959 when the first pheromone bombykol [(10 ,12 Z)-10,12-he.xadecadien-1 -ol] was identified as the female-produced sex attractant of the silkworm moth Bombyx mori, the pheromonal activity was thought to be totally due to that single compound.6 At present, it is generally believed that a pheromone is composed of many pheromone components (see Chapter 4.04), which resembles the present concept in flavor and fragrance chemistry, that is, to consider a mixture as a whole to be responsible for a particular sense of smell (see Chapter 4.15). 

If the current S. cerevisiae strains do not exhibit pronounced strain-specific effects on wine flavor, is it possible to genetically improve them to produce desired aroma components Such improvement could be accomplished by utilizing classical hybridization, protoplast fusion, mutation/selection or genetic engineering techniques (70), presupposing that the characteristic(s) to be selected for is under the control of a single gene (59). 

Stable isotopes of iron zinc and copper have been given to subjects in a variety of studies at our Center Standard doses were 4 nig Fe> 4 mg Zn and 2 mg of Cu for adult subjects Isotopes were fed in a single dose in juice at breakfast or in Trutol (a flavored glucose solution) While doses of this size are not truly tracer doses they are in the physiological range of intake Recommended daily intakes are 10 mg Fe 15 mg Zn and 2- 3 mg Cu for adult males (11) Table II shows the average absorption values obtained from subjects who were consuming diets adequate in all minerals and other dietary components ... 

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