Blue cheese

Lactic acid-producing bacteria associated with fermented dairy products have been found to produce antibiotic-like compounds caUed bacteriocins. Concentrations of these natural antibiotics can be added to refrigerated foods in the form of an extract of the fermentation process to help prevent microbial spoilage. Other natural antibiotics are produced by Penicillium wqueforti the mold associated with Roquefort and blue cheese, and by Propionibacterium sp., which produce propionic acid and are associated with Swiss-type cheeses (3). 

It lost the pimento like a college marriage and makes appearances in fancy food emporiums, hand-stuffed with chipotle peppers, blue cheese or garlic. It strikes marketing deals with the big vodka houses like Finlandia and Skyy, which package olives with liquor in promotions. 

In most odour studies researchers try to control the diet of their odour donors. In particular, consumption of garlic, onion, chilies, pepper, vinegar, blue cheese,... 

A direct effect of vasoactive amines on the organism which are not degraded in GI tracts due to the lack of mono- and diaminooxidase (MAO and DAO) or their blockade by medicines or alcohol. This group of amines includes tyramine (in Cheddar, emmental, roquefort cheeses, pickled fish, and walnuts), phenylethylamine (in chocolate), serotonin (in bananas), octopamine (in lemons), and histamine (in fermented foods, e.g., blue cheeses, but also in strawberries, tomatoes, wines, and in mackerel that have not been stored properly [scombrotoxin illness]). 

Novella-Rodriguez et al. (2003) studied the content of biogenic amines in different cheese types. The study analyzed 20 unripened cheeses, 20 hard-ripened cheeses made from pasteurized milk, 20 hard-ripened cheeses made from raw milk, 20 goat cheeses, and 20 blue cheeses (Table 6.7). 

Unripened cheese Hard-ripened cheese, pasteurized milk Hard-ripened cheese, raw milk Goat cheese Blue cheese... 

Day EA, Anderson DF. 1965. Gas chromatographic and mass spectral identification of natural components of the aroma fraction of blue cheese. J Agric Food Chem 13 2-4. 

Trihaas, J. (2004) E-nose in Danish blue cheese production. Eur Dairy Mag 4 13-14. 

Lipase Triglycerides + HzO -> fatty acids + partial glycerides + glycerol Off flavours in milk flavour development in Blue cheese... 

Extensive lipolysis also occurs in Blue cheese varieties in which the principal lipase is secreted by P. roqueforti (Chapter 10). It is claimed that treatment of Blue cheese curd with PGE improves and intensifies its flavour but this practice is not widespread. Several techniques have been developed... 

All cheeses are salted, either by mixing dry salt with the drained curd (confined largely to English varieties), rubbing dry salt on the surface of the pressed cheese (e.g. Romano or Blue cheeses), or by immersion of the pressed cheeses in brine (most varieties). Salt concentration varies from c. 0.7% (c. 2% salt-in-moisture) in Emmental to 7-8% (c. 15% salt-inmoisture) in Domiati. 

Extensive lipolysis occurs in two families of cheese in which fatty acids and/or their degradation products are major contributors to flavour, i.e. certain Italian varieties (e.g. Romano and Provolone) and the Blue cheeses. Rennet paste, which contains pre-gastric esterase (PGE) rather than rennet extract, is used in the manufacture of these Italian cheeses. PGE is highly specific for the fatty acids on the sn-3 position of glycerol, which, in the case of milk lipids, are predominantly highly flavoured short-chain fatty acids (butanoic to decanoic). These acids are principally responsible for the characteristic piquant flavour of these Italian cheeses. 

Blue cheeses undergo very extensive lipolysis during ripening up to 25% of all fatty acids may be released. The principal lipase in Blue cheese is that produced by Penicillium roqueforti, with minor contributions from indigenous milk lipase and the lipases of starter and non-starter lactic acid bacteria. The free fatty acids contribute directly to the flavour of Blue cheeses but, more importantly, they undergo partial /J-oxidation to alkan-2-ones (methyl O... 

Table 10.6 Typical concentrations of alkan-2-ones in Blue cheese (from Kinsella and Hwang,...

Samples G and H of very small batches of experimental Blue cheese ripened for 2 and 3 months, respectively. d Trace. 

The level of proteolysis in cheese varies from limited (e.g. Mozzarella) through moderate (e.g. Cheddar and Gouda) to very extensive (e.g. Blue cheeses). The products of proteolysis range from very large polypeptides, only a little smaller than the parent caseins, to amino acids which may, in turn, be catabolized to a very diverse range of sapid compounds, including amines, acids and sulphur compounds. 

The use of homogenized milk for cheesemaking has been reviewed by Peters (1964). The advantages of homogenized milk in the manufacture and ripening of cheese are (1) lower fat losses in whey and therefore a higher yield, (2) reduced fat leakage of cheese at room temperatures, and (3) increased rate of fat hydrolysis and, therefore, desired flavor production in blue cheese. 

Homogenized milk is generally not used for cheesemaking because of the cost and potential increase in hydrolytic rancidity in cheese. There are a few major exceptions cheese spreads, cream, Neufch tel, and blue cheese (Kosikowski 1977). 

The flavor of blue cheese is produced by a combination of free fatty acids and methyl ketones derived from fatty acids. The partial oxidation of fatty acids to methyl ketones occurs via the /3-oxidation pathway (Kinsella and Hwang 1976A). 

Le Bairs, D. and Gripon, J. E. 1981. Role of Penicillium roqueforti proteinases during blue cheese ripening. J. Dairy Res. 48, 479-487. 

A very well known dairy product is Roquefort cheese, its flavour is generated by mould action. This so called Blue cheese flavour is attributed to methyl ketones and is formed by the degradation of fatty acids by Penicillium roquefortii. The production of these bioflavours has also been investigated by our group [12,13] and will not be further discussed here. 

Gonzalez de Llano et al. (47) separated amino acids from low-molecular-weight peptides by means of size-exclusion chromatography on Sephadex G-10, with water as the solvent, as a preparatory step before RP-HPLC analysis of peptides from blue cheeses soluble in 5% PTA (Fig. 1). This technique has also been used (51a) to eliminate the amino acids from the ethanol-... 

The reaction of amines and amino acids with orthophthaldehyde has been widely used in postcolumn and precolumn derivatization in analyses of foods (99-104) and in analyses of peptides from biological samples. Figure 2 (87) presents a chromatogram for OPA derivatives of tryptic peptides from two proteins. The sensitivity of the method was on the order of picomoles. The authors have themselves performed postcolumn OPA derivatization of low-molecular-weight peptides from blue cheeses separated by reversed-phase chromatography (86). 

Godinho, M. and Fox, P. F. (1981). Ripening of Blue cheese Influence of salting rate on lipolysis and carbonyl formation. Milckwissenschaft 36,476-478. 

Gonzalez de Llano, D., Ramos, M., and Polo, C. (1987). Gel filtration and high performance liquid chromatographic analysis of phosphotungstic acid soluble peptides from blue cheeses. Chromatographia 23, 764-766. 

Gonzalez de Llano, D., Polo, M. C., Ramos, M. And, and Martin-Alvarez, P. (1991). Free and total amino acids in the non-protein fraction of an artisan blue cheese during ripening. Z. Lebensm.-Unters. Forsch. A 193, 529-532. 

Histamine found in foods which undergo a fermentation process, e.g., blue cheese, beer, sourkraut, and pickles. What is more, tomatoes and strawberries also contain a large amount of this biogenic amine. Both types can induce nettle rash in small children and elderly people. 

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