Aroma cheese

In addition to bacterial conversion of L-methionine to cheese aroma compounds, certain cheese-ripening yeasts have been implicated. They include De-baromyces hansenii, Geotrichum candidum, and Yarrowia lipolytica, in addition to Kluyveromyces lactis and Saccharomyces cerevisiae (previously noted). Of these yeasts, Geotrichum candidum was most effective at producing sulfur compounds with the major product being S-methyl thioacetate, with smaller amounts of MT, DMS, DMDS, and DMTS. Kluyveromyces lactis had a similar profile, but produced a much smaller amount of S-methyl thioacetate than did G. candidum. S-Methyl thioacetate is formed by a reaction of MT and acetyl-CoA (Equation 7) ... 

Jou, K.D., Harper, W.J. (1998) Pattern recognition of Swiss cheese aroma compounds by SP-MEIGC and an electronic nose. Milchwissenschaft 53 259-263. 

Several of the smaller volatile compounds formed from the catabolism of products of primary proteolysis (e.g., amino acids) can be determined by GC. The development of capillary columns and interfacing GC with MS has noticeably increased the sensitivity of this analysis. Over 200 volatile compounds have been identified in Cheddar cheese. A list of several of these compounds can be found elsewhere (Fox et ah, 2004a Singh et ah, 2003). The instrumental techniques available for the characterization of cheese aroma were also discussed recently (Le Quere, 2004 Singh et al., 2003). 

Femandez-Garcia, E. (1996). Use of headspace sampling in the quantitative analysis of artisanal Spanish cheese aroma. J. Agric. Food chem. 44,1833-1939. 

Manning, D. J. and Robinson, H. M. (1973). The analysis of volatile substances associated with Cheddar cheese aroma. J. Dairy Res. 40, 531-537. 

Bullens, 1994 Anonymous, 1996). Textural defects include increased firmness, rubberiness, elasticity, hardness, dryness, and graininess. The negative flavor attributes of reduced-fat Cheddar include bitterness (Ardo and Mansson, 1990) and a low intensity of typical Cheddar cheese aroma and flavor (Banks et al., 1989 Jameson, 1990). Approaches used to improve the quality of reduced-fat cheese include ... 

Whereas aroma-relevant amounts of y-lactones from raspberries are not detectable, their 5-Cg, 5-CjQ-lactones are enantiopure S-enantiomers [42]. In cheddar cheese-aroma the enantiomeric purity of (5R)-5-lactones (Cjq-C 4) increases with increasing side chain length [68]. 

In many cases, molds such as Penicillium and Trichoderma produce volatiles only in the spore producing stage. Methyl ketone and blue cheese aroma generation by certain Penicillium species is a good example. Another example is Penicillium decumbens which produces characteristic odor only on media which allow sporulation... 

Volatile sulfur compounds are found in most cheeses and can be important flavor constituents. The origin of sulfur-containing compounds is generally thought to be the sulfur-containing amino acids methionine and cysteine (Law, 1987). As Cys is rare in the caseins (occurring at low levels only in Os2- and K-caseins, which are not extensively hydrolyzed in cheese), the origin of sulfur compounds must be primarily Met. Sulfur compounds formed from Met include H2S, dimethylsulfide, and methanethiol. The importance of methanethiol and related compounds in cheese aroma is discussed by Law (1987). 

The total concentration of free fatty acids is usually determined by extrac-tion/titration methods or spectrophotometrically as Cu soaps. Early attempts to quantify the concentration of individual short-chain fatty acids involved steam distillation and adsorption chromatography. Complete separation and quantitation of free fatty acids can be achieved by GC, usually as their methyl esters, for which several preparative techniques have been published. Free fatty acids are major contributors to the flavor of some varieties, e.g., Romano, Feta, and Blue in the latter, up to 25% of the total fatty acids may be in the free form. Short chain fatty acids are important contributors to cheese aroma, while longer chain acids contribute to taste. Excessive concentrations of either cause off-flavors (rancidity) and the critical concentration is quite low in many varieties, e.g., Cheddar and Gouda. 

Compounds responsible for cheese aroma are volatile. While some preliminary work on the volatile constituents of cheese was done before 1960, e.g., short chain fatty acids and amines, significant progress was not possible until the development of GC in the 1950s. GC was first applied to the study of Cheddar cheese volatiles by Scarpellino and Kosikowski (1962) and McGugan and Howsam (1962), who used vacuum distillation and cold... 

Lipase from pancreas or Rhizopus nigricans Triacylglycerol Glycerol + Fatty acids Isolation of labile fatty acids, improvement of cheese aroma, cocoa processing, digestion aid. 

Prod, by microorganisms e.g. Aspergillus niger. Isol. from berries of Vaccinium vitis-idaea. Component of cheese aroma. 

The main role of propionic acid bacteria in cheese ripening consists in the utilization of lactate produced by lactic acid bacteria as an end product of lactose fermentation. Lactate is then transformed into propionic and acetic acids and CO2. The volatile acids provide a specific sharp taste and help preserve a milk protein, casein. Hydrolysis of lipids with the formation of fatty acids is essential for the taste qualities of cheese. The release of proline and other amino acids and such volatile compounds as acetoin, diacetyl, dimethylsulfide, acetaldehyde is important for the formation of cheese aroma. Carbon dioxide released in the processes of propionic acid fermentation and decarboxylation of amino acids (mainly) forms eyes, or holes. Propionic acid bacteria also produce vitamins, first of all, vitamin At the same time, an important condition is to keep propionibacteria from growing and producing CO2 at low temperatures, since this would cause cracks and fissures in cheese. 

Propionibacteria bread making and cheese aroma production. Abstr 1st Int Symp Dairy Propionibacteria, Rennes, France, C21... 

Cheese aroma concentrates offered on the market have an aroma intensity at least 20-fold higher than that of normal cheese. They are produced hy the combined action of lipases and Penicil-lium roqueforti using whey and fats/oUs of plant origin as substrates. In addition to C4-C10 fatty acids, the aroma is determined by the presence of 2-heptanone and 2-nonanone. 

From the results obtained in this study, it can be inferred that the use of GC-MS in combination with adequate aroma sampling techniques can solve analytical problems of aroma characterization, even in the case of very complex matrices. The combined use of the two extraction procedures proved helpful in providing a complete fingerprint of the aged Parmigiano-Reggiano cheese aroma, which can be used as a useful reference for the characterization of the product. 

Thermal desorption concentrates the collected cheese aroma constituents into a narrow elution band for GC-MS analysis. Each sorbent tube of the individual cheese samples was thermally desorbed by evaporating them inverse to the sampling direction into the GC carrier gas stream using an automated thermal desorber. 

Mongenot N, Charrier S, ChaUer P. 2000. Effect of ultrasound emulsdfication on cheese aroma encapsulation. J Agric Food Chem 48 861-867. 

Amarita, R, de la Plaza, M., Fernandez De Palencia, R, et al. (2006) Cooperation between wild lactococcal strains for cheese aroma formation. Food Chem 94, 240-246. 

Kieronczyk, A., Skeie, S., I angsrud, T., and Yvon, M. (2003) Cooperation between Lactococcus lactis and nonstarter lactobadlU in the formation of cheese aroma from amino acids. Appl Environ Microbiol 69, 734-739. 

In this section, the application of SAFE for the analysis of cheese aroma and the analysis of volatile fragrance components in washing powder is demonstrated. 

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