Key Components in Foods

Historically, modem aroma research began with the isolation and identification of aroma compounds in foods. It was thought that if we could identify all of the aroma compounds in foods, we would be able to reproduce the aroma of that food by formulating a flavor based on the analytical data. This did not prove to be the case. Researchers found that there were very large numbers of aroma compounds present in foods and not all could possibly be contributors to the aroma of a food. Thus, an era began where researchers attempted to determine which aroma compounds were traly needed to recreate the aroma of a food. It was postulated that somewhere between 20 and 30 compounds should be adequate to reproduce the aroma of a food. The question then was, which compounds were needed Several approaches were developed to meet this challenge. These methods will be briefly discussed. 

The earliest work in this area is now more than 45 years old [63]. Patton and Josephson [63] proposed estimating the importance of an aroma compound to the sensory character of a food by calculating the ratio of the concentration of a compound in a food to its sensory threshold in that food. This ratio is known now as 

FIGURE 3.10 Schematic of the GC/O system used in obtaining CHARM data. (From Acree, T.E., Flavor Measurement, C.T. Ho, C.H. Manley, Eds., Marcel Dekker, New York, 1993, p. 77. With permission.) 

The NIF (or SNIP) method was developed by PoIUen et. al. [73] (see also [74]). In this method, eight to ten untrained individuals sniff the GC effluent (one at a time). They simply note when they smell an odor. The aroma isolate used is adjusted 

FIGURE 3.11 GC/O system used by McDaniel for obtaining OSME data. (From McDaniel, M.R., R.Miranda-Lopez, B.T. Watson, N.J. Micheals, L.M. Libbey, Flavors Off-Flavors 89, G. Charalambous, Ed., Elsevier Publ., Amsterdam, 1990, p. 23. With permission.) 

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Once the benefits of a key component in food are documented, the challenge is to increase its concentration, and presumably its benefits, while maintaining safety. For example, isoflavones in soy are phytoestrogens with a chemical structure similar to estrogen. Isoflavones may reduce cholesterol, but what is the risk of increasing the intake of a compound that may modulate estrogens Knowledge of the toxicity of functional food components is crucial to improve their benefit-risk ratio. The efforts... 

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