Flavor investigations

Off-flavors in food packages are not only a legal but also often an economic problem, when market recalls have to be made. This chapter describes the different kinds, origins and development of off-flavors and deals with solutions for off-flavor problems arising from interactions between packaging and food. The text covers the sensory and analytical methods used for off-flavor-investigations and describes several case studies. 

Sevenants, M.R. Sanders, R.A. Anatomy of an of-flavor investigation the Medicinal cake mix. Anal. Chem. 1985, 56, 293A-298A. 

Maga, J.A. A review of flavor investigations associated with the soy products raw soybeans, defatted flakes and flours, and isolates. /. Agric. Food Chem. 1973,21, 864—868. 

This long wort boiling time is Important in that most of the mass (80-90%) of typical hop oil is made up of terpene and sesquiterpene hydrocarbons which are either steam distilled out of the wort, polymerized or oxidized to more water soluble compounds during the process (, 5, 11, 12). As a result, these hydrocarbons are not found in beer (, 5, T) and therefore are not responsible for this flavor. Investigators in this field do agree that this... 

M. R. Sevenants and R. A. Sanders, Anatomy of an off-flavor investigation The medicinal cake mix. Analytical Chem. 56 293A (1984). 

The odor detection-threshold values of organic compounds, water, and mineral oil have been determined by different investigators (Table 2 and 3) and may vary by as much as 1000, depending on the test methods, because human senses are not invariable in their sensitivity. Human senses are subject to adaption, ie, reduced sensitivity after prolonged response to a stimulus, and habituation, ie, reduced attention to monotonous stimulation. The values give approximate magnitudes and are significant when the same techiriques for evaluation are used. Since 1952, the chemistry of odorous materials has been the subject of intense research (43). Many new compounds have been identified in natural products (37—40,42,44—50) and find use in flavors. 

Nearly half of the U.S. domestic food consumption of peanuts in 1993 was as peanut butter salted peanuts, at 27.3%, and peanut candy, at 23.9% made up the other half (137). Although the per capita domestic peanut consumption in the United States has increased steadily, the consumption in recent years has not kept pace with production. Domestic food use of peanuts has been confined almost entirely to roasted peanuts. A number of investigations and developmental efforts are being made to extend the use of nonroasted peanut products such as flour and meal flakes. As of the mid-1990s, market outlets for these latter products are neither sizable nor firmly established. The food-use patterns emphasize the uniqueness and demand for products having a distinct roasted-peanut flavor. The development of the desired flavor as well as the storage stability of such flavor in peanut-food products are therefore important. 

With the publication of several books on this subject [2-9] during the past 20 years, the pace of research on the biochemistry of the C-F bond has quickened, and many new investigators have joined the field This sechon presents an overview so that the reader can sense the flavor and excitement of research in this area and observe the directions of some of the significant invesngauons TTie most thorough and up-to-date coverage will be found in reference 9, from which much of the subsequent discussion has been drawn... 

The diazines pyridazine, pyrimidine, pyrazine, and their benzo derivatives cinnoline, phthalazine, quinazoline, quinoxaline, and phenazine once again played a central role in many investigations. Progress was made on the syntheses and reactions of these heterocycles, and their use as intermediates toward broader goals. Some studies relied on solid-phase, microwave irradiation, or metal-assisted synthetic approaches, while others focused attention more on the X-ray, computational, spectroscopic, and natural product and other biological aspects of these heterocycles. Reports with a common flavor have been grouped together whenever possible. 

Mushrooms have been investigated with especial reference to shiitake, Lentinus edodes, the flavorful fungus widely used in Chinese and Japanese dishes. While the umami taste is attributed to guanylic acid, lentinic acid 14 (Scheme 6) is converted to lenthionine, 1,2,3,5,6-pentathiacycloheptane 15, a compound with the characteristic shiitake flavor. This complex reaction requires a C-S lyase enzyme.30 Other important flavor compounds are 1,2,4,6-tetrathiacycloheptane 16 (Scheme 6) and 1,2,3,4,5,6-hexathiacycloheptane (not shown). 

Since antiquity, animal milks have been converted by empirical processes to a wide variety of cheeses. With the development of microbiology as a scientific discipline, the critical role of microorganisms - bacteria, fungi, yeasts - in cheese began to be understood. Today, more than 650 cheese types are recognized and the flavor(s) of cheese has (have) now been investigated for more than a century.33 Typically, the situation is complex and the literature is enormous. For instance, more than 200 volatiles occur in Cheddar cheese. In a listing of 58 of these volatiles, 7 are sulfur compounds dimethyl sulfide (DMS),... 

In 2003, we presented two reviews concerning spin-forbidden reactions in transition metal chemistry (10,16). A number of other reviews in 2004 addressed closely related topics (90,91). However, since then, we are not aware of any review on this topic. We, therefore, present a short discussion of a number of recent studies of reactivity in transition metal chemistry for processes involving changes in spin-state. The aim here is not to be exhaustive, as there are now quite a lot of studies of transition metal chemistry that address the topic of spin-state changes. Instead, this is an attempt to give a flavor of the types of question that are being addressed now and the techniques used to investigate them. 

Spiced Layer Cake. Investigation was undertaken to evaluate navy bean hulls as an alternative source of dietary fiber in spice-flavored layer cakes and to compare hull flour from beans with no heat treatment to hull flour from beans roasted for 2 min at 240°C. Results of the objective analyses performed on both the batter and the cakes indicated that the addition of 15% navy bean hulls resulted in a thicker batter, due to the high water absorbancy of the hulls however, only the batter containing the unroasted hulls was significantly more viscous than the control batter. Cakes prepared with the roasted navy bean hulls tended to be slightly more... 

Few differences were attributed to roasting of the navy bean hulls however, color of the hulls improved with heat treatment. Cakes prepared with either unheated or roasted bean hulls compared favorably to the control. Consequently, navy bean hulls are an acceptable source of dietary fiber in a flavored cake. More research should be initiated to investigate alternative uses for navy bean hulls as a dietary fiber source. 

A color superconducting phase is a reasonable candidate for the state of strongly interacting matter for very large quark chemical potential [16-20], Many properties of such a state have been investigated for two and three flavor QCD. In some cases these results rely heavily on perturbation theory, which is applicable for very large chemical potentials. Some initial applications to supemovae explosions and gamma ray bursts can be found in [21] and [22] respectively, see also [27], The interested reader can find a discussion of the effects of color superconductivity on the mass-radius relationship of compact stars in [45]... 

Abstract We investigate the phase structure of color superconducting quark matter at intermediate densities for two- and three flavor systems. We thereby focus our attention on the influence of charge neutrality conditions as well as /3-equilibrium on the different phases. These constraints are relevant in the context of quark matter at the interior of compact stars. We analyze the implications of color superconductivity on compact star configurations using different hadronic and quark equations of state. 

In Ref. [24] it has been investigated whether with the above three- flavor quark matter EoS of the NCQM strange quark matter can appear in the interior of compact stars. The constraints of fl equilibrium and charge neutrality have been applied (see below) in order to constrain the partial densities of electrons and up-, down-, strange quarks, see Fig. 3. It can be seen that strange... 

In 2006 and 2007, NIOSH investigated two flavor-manufacturing plants. Medical testing of 29 production workers identified 7 workers with fixed airways obsfrucfion who had worked in plated-powder and/or liquid flavoring work areas 4 of these workers had severe fixed airways obsfrucfion (CDC, 2007b,c). Mean work area diacetyl air concentrations using NIOSH method 2557) for plated-powder production and liquid production in one of these plants were 0.25 and 0.02 ppm, respectively (CDC, 2007b). 

The best investigated odor-taste interactions occur in conditioned flavor aversions. Tastes that precede a delayed food-related illness are often avoided after only one experience. Odors are not avoided under similar conditions. However, if taste and odor are presented together before the malaise, animals will avoid odor when encountered later by itself. Taste affects odor, but not vice versa. If only the taste intensity is increased, both taste and odor aversion increase. Conversely, if only the odor stimulus is increased, only the odor aversion increases (Garcia etal, 1986). 

In the case of diketopiperazine 13 and related compounds, dehydrogenation of the preceding diketopiperazine occurs in the side chain. A shift of the double bond into the central ring and dehydration may result in the formation of substituted pyrazines. Simple pyrazines are known as signaling compounds from animals. The pyrazines 16 and 17 have also been isolated from marine Streptomycetes [106]. GC/MS investigations of bacterial flavor components [951 indicate that these and others are very wide-spread. 

---