Flavor chemist

Flavor has been defined as a memory and an experience (1). These definitions have always included as part of the explanation at least two phenomena, ie, taste and smell (2). It is suggested that in defining flavor too much emphasis is put on the olfactory (smell) and gustatory (taste) aspects (3), and that vision, hearing, and tactile senses also contribute to the total flavor impression. Flavor is viewed as a division between physical sense, eg, appearance, texture, and consistency, and chemical sense, ie, smell, taste, and feeling (4). The Society of Flavor Chemists, Inc, defines flavor as "the sum total of those characteristics of any material taken in the mouth, perceived principally by the senses of taste and smell and also the general senses of pain and tactile receptors in the mouth, as perceived by the brain" (5). 

The flavor chemist is responsible for the basic knowledge of sensory and appHcation properties of each of this large number of raw materials the large number of possible combinations of these items to produce specifically flavored finished compounds is readily apparent. It is not uncommon to develop a flavor that combines essential oils, plant extractive, fmit juices, and synthetics. The choice of materials depends on type of product, conditions of manufacture, labeling, and intended use. 

A flavor differential item is an additive or combination of additives that when smelled or tasted has Httle, if any, character reminiscent of the named flavor. It gives roundness and fixation to the flavor. It may be added by the flavor chemist to confuse simulation of the flavor, and it is neither characteristic of, nor essential to, the intended flavor. The greatest examples of creativity are found in this area. 

Multifaceted Nature of the Flavohsts," papers presented by the Society of the Flavor Chemists, Rutgers University, New Bmnswick, N.J., 1974. 

Society of Flavor Chemists, Inc., 11 563 Society of Rheology nomenclature, 21 704 Society of the Plastics Industry, The (SPI) on PVC recycling, 25 680 recycling coding system of, 25 681 Sociopolitical dimensions, of sustainable development, 24 189—190 Socks (mid-calf)... 

The techniques for trapping, concentrating, isolating, and identifying volatiles have been developed by flavor chemists and insect pheromone researchers and are not detailed here. Some of the techniques useful for mammals are summarized in Albone (1984) and Millar and Haynes (1988). 

Leffingwell JC (2004) Reflections on a half century of flavor chemistry. Speech at the 50th anniversary flavor symposium in October 2004 of the Society of Flavor Chemists. http //www. flavorchemist.org... 

Why is that Why is chocolate the most frequently mentioned food in surveys about cravings (Actually, this is mostly true for young women men crave pizza.) While some scientists have argued that the cause Is certain compounds, such as anandamide or caffeine, which do have the potential for pharmacological activity, the consensus is that chocolate is addictive because of its flavor. Not its taste, however. Flavor is more than just taste smell and texture also come into play. Flavor chemist Dr. Sara Kisch proved this very effectively at the chocolate symposium. She handed out jelly beans of various flavors and asked us to sample them while holding our noses. They were indistinguishable. But identification was no problem once our nostrils were liberated. It was a dramatic demonstration of the role smells play in flavor detection. When the nose is pinched, no air can flow from the mouth to the nasal passage, where our... 

Aroma compounds are present in the volatile fractions of foods. Since flavor chemists previously did not discriminate between an odorless volatile compound and a flavor compound, until now, more than 6000 volatile compounds have been identified in foods [2,... 

Flavor chemists are chemists who develop new food flavors by combining natural and artificial ingredients. A flavor chemist is just one type of food scientist. Food scientists are always searching for better ways to prepare, present, and preserve food. 

But the human nose has no difficulty in distinguishing chocolate from roast beef, and the flavor chemist is trying to catch up with this degree of discrimination. 

Throughout the years, flavor chemists have been deeply interested in the thermal reaction of various forms of carbohydrates due to the formation of both desirable and undesirable flavors and colors. Previous reviews covering specific carbohydrates are... 

Flavor chemists have traditionally relied on mass spectrometry in conjunction with gas chromatography (GC/MS) to identify the structures of volatile flavor components in heated food systems. Mass spectrometry provides the molecular weights of fragment ions, which are useful for deducing-molecular structure. The MS detection limit is on the order of 1CT g, however detection limits for target compound analysis or chemical class detection via selected ion monitoring can be much lower. Extensive libraries of mass spectra are available even so, many new flavor compounds can often not be identified from MS data alone. 

We hope that this manuscript will encourage flavor chemists to understand and better utilize the modern techniques available in mass spectrometry. In particular we believe these desorption techniques and associated chromatographic interfaces to be especially useful for the is of food derived peptides, amino acids, polyhydroxypyrazines and other polar or high molecular weight components of caramelization and Maillard reactions. 

The identification of these types of compounds in meat flavor remains a major challenge to the flavor chemist with sophisticated modern analytical tools. 

Although it is common to assert that there are only four distinct taste sensations, even a casual introspection reveals that other oral sensations can be distinguished. As one may expect, flavor chemists have discovered that many separate oral sensations are required to reconstruct the flavors of foods and beverages. Some of these sensations have distinct oral loci from which they are elicited by specified types of chemical compounds, thus indicating that different neural systems are involved. Many of these sensations are difficult to typify verbally and also often have affective overtones. These sensations are the result of considerable peripheral and central neural processing and are only indirectly related to the peripheral neural pulse signals as discussed above. The type of sensation elicited and the locus of elicitation provide us with further measures of the functional properties of oral chemoreceptor systems. 

Pyrazines. In the thirties, the attention on pyrazines was focused on its industrial role in dyes, photographic emulsions and chemotherapy. Its importance in life processes was indicated in its derivative, vitamin B2 (riboflavin, 6,7-dimethyl-9-(l -D-ribityl isoalloxazine). Later,in the midsixties, it was identified in foods and its contributions to the unique flavor and aroma of raw and processed foods attracted the attention of flavor chemists Pyrazine derivatives contribute to the roasting, toasting, nutty, chocolaty, coffee, earthy, caramel, maple-like, bread-like, and bell pepper notes in foods. The reader is referred to the reviews on Krems and Spoerri (88) on the chemistry of pyrazines, and the review of pyrazines in foods by Maga and Sizer (89, 90) Table XVI summaries sensory description and threshold of selected pyrazines. 

Taste has long been considered to consist of only four sensations that contribute little to most food flavors. These four feeble sensations were linked to a simplistic taste chemistry that had little relevance to modem chemistry. These conceptions, often repeated, not only totally ignore the major role taste plays in food selection and the control of ingestion, but also are not followed in practice by much of the flavor industry. Thus you will often discover upon reading the literature that the odors of a food were best, or perhaps only, realized when food was in the mouth. Many flavor chemists have found that in order to adequately define a food flavor, tastes other than the four basics must be postulated. The types of taste active compounds in foods encompass much of natural product chemistry. Many of the compounds presently identified as odors are strongly taste active. 

Masashi Ishikawa was born in 1937 in Morioka City, Iwate, Japan. He majored in biological chemistry from Iwate University. He joined T. Hasegawa Co., Ltd. in 1959 as a flavor chemist and is now the Director and Senior Deputy President. He received his Ph.D. in 2003 from The Graduate School of Agriculture and Life Sciences, University of Tokyo, under the supervision of Professor Takeshi Kitahara. 

Gas chromatography remains our most powerful separation technique probably because of this, it has become the most widely used of all analytical techniques. The major limitation to its application, of course, is that it is restricted to the separation of compounds which possess (or which can be derivitized to compounds which do possess) suitable vapor pressures, or "volatility . Volatility, however, is a necessary attribute of odorous compounds, and aroma exercises a profound influence on flavor. Hence, it is not surprising to find that gas chromatography has received a great deal of attention from the flavor chemist, and that many of the advances in gas chromatography have been made by those in the flavor field. 

Even partial resolution of these very complex samples requires the use of very efficient columns. In general, separation efficiency varies inversely with column capacity. Sniff-testing of the column effluent can be very useful to the flavor chemist, but this demands columns of even larger sample capacity. Hence the flavor chemist has been faced with a difficult choice 1) better resolution of volatile flavor compounds in amounts too small for their sensory evaluation, or 2) sniff testing of poorly resolved multi-component peaks. 

There have been many advances in the field of gas chromatography, and the rate at which new developments occur has been increasing in a manner that is almost exponential. Among those developments are some that hold special significance for the flavor chemist these include advances in 1) sample preparation, 2) injection hardware and methodology, and 3) column technology. 

New developments in the gas chromatographic columns are of special interest to the flavor chemist. These include the availability of improved polar phases, columns of "non-standard dimensions (i.e. "microbore" and "megabore" columns), and columns with "super-thick" (i.e. 3 to 5 urn) films of stationary phase. 

The first five chapters of this book focus on the grape derived and varietal flavors of wines. Many of these compounds occur as nonvolatile glycosidic flavor precursors and the separation and analysis of these precursors have been a challenging and active field of research. The isolation and quantification of trace volatiles represent examples of the difficulties faced by flavor chemists as they attempt to characterize varietal flavors with sensory thresholds in the parts per trillion range and lower. 

Prior to the 1950 s only about 500 flavor compounds were known (1). Since then, with the advent of modern Instrumentlon, thousands of compounds have been characterized in hundreds of different foods (2). There have been many books published on flavor research workshops and symposia, some of which are held on a periodic basis and some on special occasions and topics, covering various aspects of flavor (3-20). Also, there are many excellent reviews which every serious flavor chemist should consult (21-43). 

Flavor chemists typically subdivide the perception of food into three types of sensations taste, smell and flavor. This latter category almost invariably consists of sensations during consumption. The flavor sensations are considered largely to arise from the stimulation of smell receptors, although research has not demonstrated this to be so. From a biological and physiological point of view, these flavor sensations have little reality. 

Flavor binding can cause a significant alteration in the perceived flavor of a food. This alteration is often detrimental to food quality because it changes the characteristic flavor prohle, but it can also be beneficial when the bound molecules are off-flavors. A flavor chemist must therefore take binding effects into account when formulating the flavor of a particular product. 

Consumers demand for authentic and home-like meal flavors prompted the flavor industry to hire corporate chefe to work side-by-side with flavor chemists in the process of flavor development. Flavors from traditional cooking techniques, that take several hours to several days to develop desired profiles, are now matched by flavor chemists. In this process, the corporate chef designs a gold standard food product, and the flavor chemist provides a match to the flavor of the gold standard. 

---