Roasted food

The second kind of commercial cocoa substitute consists of roasted food products. Clearly, whether intentionally or not, they employ Maillard technology in the same way in which it is employed in producing cocoa and coffee. The ingredients disclosures suggest that no effort has been made to modify or to enhance the flavors by the addition of amino acids or of special sugars (xylose, for example). At least three of these products are worth mentioning. 

The reaction mixtures are simpler - the number of volatile chemicals produced 1s smaller than found 1n a typical roasted food. 

Recent research has Identified numerous aroma chemicals 1n roasted foods, such that hundreds are known. Current work 1s devoted less to Identification of aroma chemicals, but more to Identification of specific flavor notes of significant Importance, and to maximizing the production of these chemicals. 

Certainly the occurance of pyrazines in cooked and roasted foods covers the proverbial "soup to nuts . 

Kahweofuran (2-methyl-3-oxa-8-thiabicyclo(3.3.0)-1.4-octadiene, 8 ) was first isolated by Stoll et al. (19) and its structure later confirmed by synthesis (3J ). This compound possesses a roasty/sulfury-note as do the related ethyl- and dimethyl derivatives are unique to coffee. So far, the ethyl and dimethyl compounds have not been detected in the roasted foods or in monosaccharide/cysteine model experiments. 

Alkylpyrazines have been Identified in virtually all roasted foods. The most common descriptions used for alkylpyrazine aroma include... 

Maleki, S.J., Chung, S., Champagne, E.T., and Raufman, J.P. 2001. Allergic and biophysical properties of peanut proteins before and after roasting. Food Allergy Tolerance 2 211-221. 

Roasting Food industry products Sulfide ores (FeS2) 200°C 1 atm 650-1100°C 1 atm... 

E. M. P. Widmark, Presence of cancer-producing substances in roasted food, Nature, 1939, 143, 984. 

Chemists produce synthetic flavourings such as smoky bacon and even chocolate . Meaty flavours come from simple heterocycles such as alkyl pyrazines (present in coffee as well as roast meat) and furonol, originally found in pineapples. Compounds such as corylone and maltol give caramel and meaty flavours. Mixtures of these and other synthetic compounds can be tuned to taste like many roasted foods from fresh bread to coffee and barbecued meat. 

III) and 2-am no-3-methyl-9H-pyrido[2,3-b]indole (IV) in a pyro-lyzate of soy protein. These fluorescent compounds could be protein-bound in roasted foods. Detailed experiments on the interaction between food proteins and such compounds of toxicological importance are being carried out in Japan. 

A similar procedure, aiming for a total flavor complex, has been followed in duplicating the flavor of many kinds of baked and roasted products, such as nuts and meats. Combinations of natural ingredients, analogous to those expected to play a role in the flavor formation of roasted foods, in particular amino nitrogen... 

However, phosgene is clearly highly toxic (threshold limit value-TLV of 0.1 ppm), but acrolein, for example, has the same TLV and is produced in quantities of several millions worldwide. Acrolein is also produced at barbecue parties by roasting foods, without provoking health alarms. Clearly, a low TLV implies the adoption of special safety procedures and limited storage. On-demand production and other safety procedures, such as those discussed above, are the solution to minimizing the risk to a sustainable level. 

The level of these potential carcinogens in some broiled or roasted foods, such as broiled sardines, is about 10 ng/g. This amount is much lower than those used in the carcinogenicity assays. The long-term cumulative effect of the carboline intake may be of great concern. In some experimental studies, tryptophan itself appears to promote the formation of tumors.287-289 Also, a tryptophan-riboflavin photoinduced adduct may have a role in the pathogenesis of hepatic dysfunction observed during parenteral nutrition.290... 

Hashim L. and Chaveron H. (1996) Use of methylpyrazine ratios to monitor coffee roasting. Food Rev. Int. 28, 619-23. 

Kadar R. and Devik O.G. (1970) Pyrazines as interfering substances in the determination of nitrosamines in roasted foods, Acta Chem. Scand. 24, 2943-8. 

Koehler P.E., Mason M.E. and Odell G.V. (1971) Odor threshold levels of pyrazine compounds and assessment of their role in the flavor of roasted foods. J. Food Sci. 36, 816-18. 

Lentner C. and Deatherage F.E. (1959) Organic acids in coffee in relation to the degree of roast. Food Res. 24, 483-92. 

Although pyrolysis of selected leaf constituents generates pyrazines, the diversity and abundance of pyra-zines in smoke cannot be adequately accounted for by this mechanism alone. Maga and Sizer (2439) and Enomoto et al. (17B12) have reviewed the occurrence of pyrazines in roasted foods and proposed pathways for pyrazine formation. Their summaries present a large array of pyrazines found in the flavor fractions of a number of roasted foods. It is striking that nearly all pyrazines commonly found in tobacco smoke have been identified in at least one roasted food. For example, 2,3-dimethylpyrazine has been found in peanuts, barley, coffee, baked potatoes, mushrooms, lamb fat, and tobacco smoke (1587a). 

Table 11.25. Antioxidant activity of some roasted foods ...

Krings, U. and Berger, R.G. Antioxidant activity of some roasted foods. Food Chem. 72, 223-229 (2001). 

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