Aroma compounds definition

The definition of oxidized fish oil-like aromas still leave fresh fish aromas undefined. Various freshly harvested fish have distinguishing aromas, but they also are characterized by a common plant-like, seaweed-like aroma. Thus, compounds and reaction pathways different from random autoxidation appear likely and reasonable. Even conflicting descriptions of fishy odors, i.e., including roles for volatile amines (2 19) and sulfur compounds (20-22), can be accommodated by the hypothesis that previously unrecognized biochemical reactions yield characterizing fresh fish aromas. These premises led to investigations (23-26) which have resulted in the identification of a group of enzymically-derived volatile aroma compounds that contribute fresh, plant-like aromas to freshly harvested fish (Table I). 

While by definition, aroma compounds need to be volatile enough to be inhaled into the nose, flavor compounds can either be volatile or non-volatile. Volatile compounds typically have molecular weights below 300 Daltons. Nonvolatile flavor compounds can have molecular weights well over 300. Detection of non-volatiles requires the use of TLC or HPLC either alone or in tandem with an identification technique. HPLC-NMR can identify non-volatile coumarins, sterols, fatty acids and psoralens, in citrus oils, such as the substituted psoralen byakangelicol, found in lemon peel oil. Non-volatiles can act as odor fixatives, impacting the release of a perfume from the skin. Non-volatiles also serve as authentication markers that are difficult to adjust or circumvent (27). 

Suffice to say that anything that remotely smells like sassafras oil or licorice or any of those strong rustic spices is going to have some amphetamine precursor, maybe not safrole exactly, but definitely something. There is just no other substitute in nature for the aroma these unique compounds give. 

At this point, it is important to clarify a few terms that are often used in the context of this chapter. Flavour is usually divided into the subsets taste and smell, which are perceived in the mouth and the nose, respectively [3], The terms aroma and odour are not well defined and often used as synonyms. Qdour is best reserved for the smell of food before it is put into the mouth (nasal perception) and aroma for the retronasal smell of food in the mouth. In this paper, we mainly use the terms aroma and taste , as well as flavour comprising sensory notes imparted by both volatile and nonvolatile compounds (odorants and tastants). In the public domain, however, taste is often used as a synonym for flavour . Proper definitions of these terms are ... 

The English language definition of aromatic is "of or having an aroma smelling sweet or spicy fragrant or pungent." Historically, aromatic compounds were identified as such by their characteristic odor. The modern chemical definition of aromatic has to do with the cyclic delocalized bonding in a molecule rather than its odor. 

As already indicated, compounds with high aroma values may contribute to the aroma of foods. The aroma value A of a compound is calculated according to the definition ... 

---