Burnt flavor

Chemical modification of simple sugars during drying, baking, or roasting operations can either have a desirable or undesirable effect upon the organoleptic quality of the final product. We have become accustomed to the characteristic roasted or baked flavors of coffee, peanuts, popcorn, and freshly-baked bread. The color and flavor and aroma of caramel make it a useful additive for the food industry. On the other hand, the burnt flavor of overheated dry beans or soy milk reduces marketability of these products. 

According to Table V the tolerable limits of iso-valeraldehyde concentration seem to be variety dependent while "Rubika" containing 1.8 ppm isovaleralde-hyde does not exhibit distinct undesirable flavor changes, "Rubin" having the same isovaleraldehyde concentration and "Pariser Markt" with an even lower amount of isovaleraldehyde already show a burnt flavor character. These findings may be attributed to the fact that... 

Its ability to more effectively direct toward the t, , -lsomer Is seen by an elevated Isomer ratio of 3.08 In the presence of Trolox C (Table II). As noted earlier, low concentrations of the , , -lsomer of 2,4,7-decatrlenal exhibit a more pronounced flshy/burnt flavor quality In oxidizing fish oils while the , , -lsomer causes more green-fishy, burnt character notes (28). Although substantial concentrations of the Cg unsaturated compounds were produced In the fish oils containing Trolox C or alpha-tocopherol (Table I), the production of 2,4,7-decatrlenals provided the underlying unpleasant, characterizing fish flavor notes. 

Short chain fatty acids are formed by peracld oxidations of autoxldatlvely-derlved n-alkanals (63), and the Incorporation of the peracld Inhibitor, dllauryl thlodlproplonate (63), Into deodorized fish oils was Investigated as a means of preventing the formation of flshy/burnt flavors. Although results of these studies showed substantial reduction of these acids to concentrations well below threshold (<10 ppb), burnt/flshy flavors... 

Another economic problem of glucosinolates is the burnt flavor of milk from cattle who have eaten the cruciferous weed Coronopus didy-mus. This is caused by benzyl methyl sulfide or benzyl mercaptan formed in the cow from the glucotropaeolin of the weed (110), presumably via the thiocyanate. Finally, ferrous ion catalyzes the nonenzymatic breakdown (H) of glucosinolates to nitriles and thioamides (111)-... 

The home trade quality constitutes the bulk of the exported rum. It has a full flavor, and chemically is characterized by a higher proportion of esters of higher fatty acids. It is generally accepted that these acids result from bacterial decomposition of the dead yeasts found in the distilling materials. As compared with local trade goods the home trade have a fuller and more fruity aroma and a marked spicy residual flavor is noted on dilution. Sometimes, even, an excess of the higher alcohols and esters which produce this result will also cause an objectionable cloudiness on dilution with water. On occasion home trade rums will have a noticeable burnt flavor resulting from over-distillation by direct fire. 

The odor threshold given by the authors is 0.01 ppb in water, with a cooked-meat aroma from 0.05-0.5 ppb becoming thiamine-like at higher concentrations. At a concentration of 0.3 ppm it has a roasted, meaty, rubbery, burnt flavor (Chemisis, 1996). 

It has a coffee-like odor (Sakaguchi and Shibamoto, 1978b), and a strong, mustard, garlic, burnt flavor (Chemisis, 1961). 

It had already been found in boiled pork liver flavor (Mussinan and Walradt, 1974) and in white bread of which it constitutes, according to Mulders et al. (1976) the characteristic component, with a threshold concentration in aqueous solution of only 0.04ppb. Indeed, its odor has been described has having a fresh white bread crust (Mulders et al., 1976 Ohloff and Flament, 1978, 1979), but with an alliaceous, burnt flavor (Chemisis, 1968). 

At 0.2-0.4 ppm in a syrup base, it has typical coffee-like flavor, a sulfury note being perceived when tasted in a neutral, soluble coffee base (Winter et al., 1976e). It is also described as having a coffee-like odor (Baltes, 1979a), a roasted, coffee, burnt flavor (Chemisis, 1994). 

It imparts a burnt flavor to a sugar syrup, at a concentration of 2 ppm (Winter et al., 1976f). 

This oxazole is characterized by a fatty and burnt flavor (Chemisis, 1976). 

The flavor in water is described as green, herbal, nutty by Pittet and Hruza (1974). At a concentration of 3 ppm, it is characterized by a horseradish, asparagus, burnt flavor at 1 ppm it becomes more floral and flowery (Chemisis, 1995). 

The organoleptic properties have been described by Winter et al. (1976r) at a concentration of 20 ppm in a syrup base it has a fruity, rose-like taste it is also characterized as having an anthranilic burnt flavor. 

At a concentration of 2.5 ppm in a syrup base, 3-ethylpyridine has been described as having a caramel, roasted and hazelnut-like taste. It imparts to a neutral soluble coffee beverage, at 0.1 ppm, a buttery, green, cereal, caramel note (Winter et al., 1977c). It is also characterized by a tobacco flavor (Fors, 1983), caramel, burnt flavor (Chemisis, 1989). 

This first member of the series was found afterwards in numerous food flavors (TNO, 1997). It has a weak, burnt flavor (Chemisis, 1975). 

Takahashi, K., M. Tadenuma, S. Sato, 3-Hydroxy-4,5-dimethyl-2(5H)-furanone, a burnt flavoring compound from aged sake, Agric. Biol. Chem., 40, p. 325, 1976. 

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