Flavor in cheese

Green, M. L. and Manning, D. J. 1982. Development of texture and flavor in cheese and other fermented products. J. Dairy Res. 49, 737-748. 

Kristoffersen, T. 1985. Development of flavor in cheese. Milchwissensch 40, 197-199. Kuzdzal-Savoie, S. 1980. Determination of free fatty acids in milk and milk products. In Flavor Impairment of Milk and Milk Products due to Lipolysis. J. H. Moore (Editor). Int. Dairy Fed. Annu. Bull. Doc. No. 118. 

Visser, S., Hup, G., Exterkate, F. A. and Stadhouders, J. 1983. Bitter flavor in cheese. 2. Model studies on the formation and degradation of bitter peptides by proteolytic enzymes from calf rennet, starter cells and starter cell fractions. Neth. Milk Dairy J. 37, 169-180. 

The role of milk-fat in the development of flavor in cheese during ripening will be discussed below although it should not be forgotten that lipolysis and the metabolism of fatty acids do not occur in isolation from other important biochemical events during ripening. 

Develops characteristic flavors in cheeses, especially Italian cheeses H2O2 is used to destroy pathogens in milk, and the residual H2O2 is removed with catalase to permit growth of a pure culture. 

Lormation of desirable or harmful compounds due to enzyme activity, e.g., development of a typical flavor in cheese or decarboxylation of amino acids in fish marinades... 

One of the major problems encountered in research on cheese flavor is defining what the typical flavor should be. Within any variety, a fairly wide range of flavor and textural characteristics is acceptable this is particularly so for Cheddar which makes it especially difficult to chemically define its flavor. In cheese factories, wholesale or retail outlets and research laboratories, somebody decides what constitutes desirable and undesirable flavor, which may not be typical. Only recently have systematic attempts been... 

Some microorganisms, such as Penicillium roqueforti, have the ability to decarboxylate sorbic acid and thus convert it into 1,3-pentadiene, which has no antimicrobial activity and in addition may contribute to an off-flavor in cheeses ... 

Sorbic acid is degraded biochemically like a fatty acid. Some microorganisms, such as Penicillium roqueforti, have the ability to decarboxylate sorbic acid and thus convert it into 1,3-pentadiene, which has no antimicrobial activity and in addition may contribute to an off-flavor in cheeses [3]. In wines, it is generally used as the potassium salt, since the acid is only sparingly soluble in wine. Studies have shown that sorbic acid will react with SO2 by addition to the C-4 double bond to form ... 

Two other practical appHcations of en2yme technology used in dairy industry are the modification of proteins with proteases to reduce possible allergens in cow milk products fed to infants, and the hydrolysis of milk with Hpases for the development of Hpolytic flavors in speciaHty cheeses. 

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),... 

Aliphatic monoketones are of minor importance as fragrance and aroma substances. 2-Alkanones (C3-C15) have been found in the volatile fractions of many fruits and foodstuffs, but they do not contribute signiflcantly to their aroma. An exception are the odd-numbered methyl ketones Cy, C9, Cn which possess a characteristic nutty note they are used, e.g., in cheese flavor compositions. In... 

For example, the color of fresh fruit indicates ripeness and the time the fruit is most likely to taste best. Off-colors in cheese or meats are associated with poor flavor quality. Generally, we expect each food product to have a certain color. Deviations from this expected color can result in rejection of a product even when this color does not adversely influence the flavor or nutritional value of the food. If plant-protein products are to attain widespread utilization in food applications, the color they impart to the product must be considered an important factor in consumer acceptability. 

Exploration of this method for controlled release of enzymes to produce flavors of importance in cheese ripening has been pioneered by Kirby and Law (1986), and was recently the subject... 

In cheese making, the casein is separated from the liquid part of the milk — the whey. It is then pressed and stored until ripe. The flavors of cheeses arc caused mostly by esters created during the ripening. 

The manufacturing process for Swiss cheese was developed in Emmen-thal, Switzerland, hence the name Emmentaler cheese (known as Swiss cheese in the United States). It is hard, pressed-curd cheese with an elastic body and a mild, nut-like, sweetish flavor. Swiss cheese is best known for the large holes or eyes that develop in the curd as the cheese ripens. S. thermophilus andL. bulgaricus or Lactobacillus helveticus are used for acid production, which aids in expelling whey from the curd, whereas Propionibacterium shermanii is largely responsible for the characteristic sweet flavor and eye formation. 

The development of a rancid flavor in milk and some other fluid products is usually undesirable and detracts from their market value. In contrast, the popularity of certain dairy products, notably some varieties of cheese, as well as some confectionery items containing milk as an ingredient, is thought to be partially due to the proper intensity of the rancid flavor. Hence, knowledge of the factors involved in the development of rancidity is of great practical importance to several industries. 

After the curd and whey are physically separated and the optimum pH level is reached, the curd is salted. Salt improves the flavor of cheese, retards microbial metabolism, and helps expel moisture from the curd. Salt is either added directly to the curd (Cheddar, Colby) or the preformed block of cheese is placed in a brine solution (almost all other cheese types). 

Excessive or insufficient acid development during manufacture can produce variability in the moisture content of cheese and defects in flavor, body, texture, color, and finish (Van Slyke and Price 1952). The rate of lactose fermentation varies with the type of cheese, but the conversion to lactic acid is virtually complete during the first weeks of aging (Van Slyke and Price 1952 Turner and Thomas 1980). Very small amounts of lactose and galactose may be found in cheese months after manufacture. (Huffman and Kristoffersen 1984 Turner and Thomas 1980 Harvey et al. 1981 Thomas and Pearce 1981). Turner and Thomas (1980) showed that the fermentation of residual lactose in Cheddar cheese is affected by the storage temperature, the salt level in the cheese and the salt tolerance of the starter used. 

S. thermophilus metabolizes lactose to l( +) lactic acid but utilizes only the glucose moiety of lactose, leaving the galactose moiety in the cheese (Tinson et al. 1982). In Swiss cheese manufacture, S. thermophilus metabolizes the lactose and L. helveticus metabolizes the galactose to d( —) and l( + ) lactic acid (Turner et al. 1983). The l( + ) lactate isomer is preferentially utilized by propionibacteria to form acetic and propionic acids, which are essential for the development of the characteristic flavor in Swiss cheese (Langsrud and Reinbold 1973). 

Shahani 1971). There is still considerable debate over the contribution of fat and its breakdown products to flavor in Cheddar cheese (Law 1984 Aston and Dulley 1982). 

Hydrolytic rancidity flavor defects in Swiss, brick, and Cheddar cheeses have been linked to high concentrations of individual short chain free fatty acids (Woo et al 1984). Lipases from psychrotrophic bacteria have been implicated in causing rancidity in cheese (Cousin 1982 Kuzdzal-Savoie 1980), although most starter streptococci and lactobacilli isolated from cheese are also capable of hydrolyzing milk fat (Paulsen et al. 1980 Umemoto and Sato 1975). Growth of Clostridium tyrobutyricum in Swiss cheese causes the release of butyric acid and subsequent rancid-off flavors (Langsrud and Reinbold 1974). The endogenous lipoprotein lipase is also responsible for hydrolytic rancidity in nonpasteurized milk. 

Paulsen, P. V., Kowalewska, J., Hammond, E. G. and Glatz, B. A. 1980. Role of microflora in production of free fatty acids and flavor in Swiss cheese. J. Dairy Sci. 63, 912-918. 

Fruity flavor in dairy products is the result of ethyl ester formation, usually catalyzed by esterases from psychrotrophic or lactic acid bacteria. Ester formation by P. fragi involves liberation of butyric and ca-proic acids from the one and three positions of milk triglycerides and the subsequent enzymatic esterification of these fatty acids with ethanol (Hosono et al. 1974 Hosono and Elliott 1974). Consequently, among the esters formed, ethyl butyrate and ethyl hexanoate predominate. Pseudomonas-produced fruity flavor can occur in fluid milk, cottage cheese, and butter. 

Fruity flavor in Cheddar cheese is also associated with high levels of ethyl butyrate and ethyl hexanoate (Bills et al. 1965). However, this defect is usually caused by esterase activity from lactic acid bacteria, especially S. lactis and S. lactis subsp. diacetylactis (Vedamuthu et al. 1966). Fruity-flavored cheeses tend to have abnormally high levels of ethanol, which is available for esterification (Bills et al. 1965). Streptococcal esterase activity in cheese is affected by the level of glutathione, which suggests a dependence on free sulfhydral groups for activity (Harper et al. 1980). 

Moskowitz, G. J. 1980. Flavor development in cheese. In The Analysis and Control of Less Desireable Flavors in Foods and Beverages. G. Charalambous (Editor). Academic Press, New York, pp. 53-70. 

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