Blue cheese lipolysis

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... 

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... 

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

Extensive lipolysis occurs in mould-ripened cheese, particularly blue varieties. In some cases, up to 25% of the total FFA may be liberated (see Gripon, 1987, 1993). However, the impact of FFA on the flavor of blue mould-ripened cheeses is less than in hard Italian varieties, possibly due to neutralization as the pH increases during ripening and to the dominant influence of methyl ketones on the flavor of blue cheese. 

Lipolysis is considered to be undesirable in most cheese varieties. Cheddar, Gouda, and Swiss-type cheeses containing even a moderate level of free fatty acids would be considered rancid however, certain cheese varieties are characterized by extensive lipolysis (e.g., Romano, Parmesan, and Blue cheeses). Bills and Day (1964) quantified FFA ( 2 0 to Cj8 3) in 14 Cheddar cheeses with wide variations in flavor but found only small differences, qualitatively or quantitatively, between cheeses of different flavor. The... 

Lactones have very low flavor thresholds (Kinsella et al, 1965). Jolly and Kosikowski (1975b) found that the concentration of lactones in Blue cheese was higher than that in Cheddar and concluded that the extensive lipolysis in Blue cheese influences the formation of lactones 5-Ci4 and 5-C16 were the principal lactones in Blue cheese (as found also for Cheddar) (Wong et al, 1973). A stronger typical Blue cheese flavor was found in cheeses containing added lipase, perhaps because lactones blend or modify harsher flavors. 

Similar reactions following mould-induced lipolysis are responsible for the characteristic flavours of various soft and blue cheeses. 

An important but imdefined role of milk fat in the development of natural cheese flavour characteristics is well known (Law et al., 1973). Free fatty acids and presumably lipolysis of fats, play a major role in the development of desirable flavours in mould ripened cheese (Nelson, 1972). Blue cheese t)rpe flavours could be developed from mixtures of skimmed milk and homogenized cream, the homogenization favouring liberation of free fatty adds by milk lipases (Hammer and Lane, 1937). 

The mode and extent of milk fat degradation de- 10.28. Lipolysis during ripening of blue cheese 1... 

Lipolysis by P. roqueforti is necessary for flavor development in blue-vein cheese. P. roqueforti produces intracellular and extracellular li-... 

Lipolysis plays an important role in providing the characteristic flavor of many milk products. In particular, the ripening of most cheese varieties is accompanied by lipolysis due to microorganisms or to added enzyme preparations, and, in raw milk cheese, to the milk LPL. Lipolysis is not extensive, but is more pronounced in some cheeses (e.g., blue-veined and hard Italian varieties), than in others. Excessive lipolysis renders the cheese unacceptable (Fox and Law, 1991 Gripon et al., 1991). 

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