Flavor water-soluble precursors

Many desirable meat flavor volatiles are synthesized by heating water-soluble precursors such as amino acids and carbohydrates. These latter constituents interact to form intermediates which are converted to meat flavor compounds by oxidation, decarboxylation, condensation and cyclization. 0-, N-, and S-heterocyclics including furans, furanones, pyrazines, thiophenes, thiazoles, thiazolines and cyclic polysulfides contribute significantly to the overall desirable aroma impression of meat. The Maillard reaction, including formation of Strecker aldehydes, hydrogen sulfide and ammonia, is important in the mechanism of formation of these compounds. 

Raw meat has little desirable flavor, but each type of meat has a characteristic flavor due to the animal species and the temperature and type of cooking. Both water-soluble and lipid-soluble fractions contribute to meat flavor and the water-soluble components include precursors which upon heating are converted to volatile compounds described as "meaty."... 

In their recent comprehensive review of natural and synthetic meat flavors, MacLeod and Seyyedain-Ardebili (20) listed 80 patents describing "reaction products" procedures that produced meat-like flavors upon heating. Approximately one-half of these precursor mixtures included amino acids and reducing sugars. Most of the mixtures described in patented procedures for synthetic meat flavor are modeled after ingredients found in the water-soluble dialy— zable fraction of fresh meat. These constituents serve as reagents for Maillard reactions. 

Diffusate powder prepared by freeze-drying dialyzable water-soluble solutes from beef is undoubtedly the best precursor mixture for producing "meaty" odor and flavor since it is these ingredients that are largely responsible for the flavor of cooked meat. 

In this study the physical parameters involved in interaction of a major class of meat flavorants, methyl pyrazines, with soy proteins were determined at meat roasting temperatures. Beef diffusate, the water soluble, low molecular weight fraction that constitutes about IX of beef, was shown to contain the necessary precursors to obtain a desirable, thermally generated meat aroma (8). Diffusate was heated under controlled conditions and generated volatiles were transferred to a gas chromatograph for separation and quantitation. Methyl pyrazines, either from heated diffusate or from standard solutions, were measured in the presence of purified soy proteins and the thermodynamics of binding were determined. 

Mabrouk, A.F., Jarboe, J.K., O Connor, E.M. Water-soluble flavor precursors of beef Extraction and fractionation. J. Agric. Food Chem. 1969,11, 5-9. 

The major precursors in meat flavors are die water-soluble components such as carbohydrates, nucleotides, thiamine, peptides, amino acids, and the lipids, and Maillard reaction and lipid oxidation are the main reactions that convert these precursors in aroma volatiles. The thermal decomposition of amino acids and peptides, and the caramelization of sugars normally require temperatures over 150C for aroma generation. Such temperatures are higher than those normally encountered in meat cooking. During cooking of meat, thermal oxidation of lipids results in the formation of many volatile compounds. The oxidative breakdown of acyl lipids involve a free radical mechanism and the formation of... 

Thiamin plays an essential role in different foods as a water soluble vitamin. Additionally, its function as a flavor precursor in heated foods, e.g. meat, should not be neglected. But certainly, this aspect depends very much on its amoimt and the specific conditions in the food system. Another important field in which thiamin plays a remarkable role is the application of flavorings. Along with carbohydrates, amino acids, ribonucleotides, and other constituents, thiamin is widely used as a flavor precursor. This fact is clearly demonstrated by many patented reaction or processed flavors. 

Wasserman, A.E., N. Gray, Meat flavor. I. Fractionation of water-soluble flavor precursors of beef, J. Food ScL, 1965. 30, 5, p. 801. 

C. Determination of Water-Soluble Meat Flavor Precursors... 

Some of the early work on meat flavor chemistry examined potential water-soluble precursors in raw meat and changes that occurred during cooking. The earliest report of the analyses of sugar in meat was that of Tarr and associates in 1954 [10], who used paper chromatography to identify glucose... 

Table 1 Concentrations of Some Water-Soluble Flavor Precursors in Beef from Animals Raised on Grass and Concentrate Diets, Showing the Range of Values ( = 24)...

HLA Tarr. The MaiUard reaction in flesh foods. Food Technol 8 15-19, 1954. RL Macy, HD Naumann, ME Bailey. Water-soluble flavor and odor precursors of meat. I. Qualitative study of certain amino adds, carbohydrates, non-amino acid nitrogen compounds, and phosphoric acid esters of beef, pork, and lamb. J Food Sd 29 136-141, 1964. 

Because of the presence of extremely small aqueous droplets, a w/o mi-croemulsion is an excellent medium to minimize spattering during open pan frying. El-Nokaly et al. [3,36] formulated edible Crisco oil-based w/o microemulsions containing solubilized water-soluble additives such as nutrients, vitamins, flavors, or flavor precursors in the oil using a well-selected combination of oils, polar liquids, and surfactants. Water-soluble additives that can be dispersed in the aqueous core of microemulsions can be the following ... 

Fats act as precursors to flavor development by interacting with proteins and other ingredients when heated. Off-flavors are not normally perceived in full-fat systems because most of them are fat-soluble. However, in the absence of fat, the vapor pressure of the aroma chanical in water is increased, resulting in a very intense perception of the off-flavor chemical. Flavor release is a critical factor governing smell and taste. The majority of flavor components are dissolved to some extent in the lipid phase of food— releasing the flavor slowly in the mouth and resulting in a pleasant aftertaste [75]. 

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