Cheese ripening lipolysis during

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... 

Lipolysis is considered to be an important biochemical event during cheese ripening and the current knowledge have been discussed in detail (Collins et al., 2003, 2004 McSweeney and Sousa, 2000). The formation of short-chain FFAs by the lipolysis of milk fat by lipases is a desirable reaction in many cheese types (e.g., mold-ripened cheeses). The catabolism of FFAs, which is a secondary event in the ripening process, leads to the formation of volatile flavor compounds such as lactones, thioesters, ethyl esters, alkanols, and hydroxyl fatty acids. The contributions of lipolysis to the flavor of bacterially ripened cheeses are limited. 

Other nonstarter bacteria (e.g.. Micrococcus and Pediococcus) also produce lipases. It is generally believed that lipases from Micrococcus spp., when present in cheese, can contribute to lipolysis during ripening (Bhow-mik and Marth, 1990b). The lipase of M. freudenreichii was strongly inhibited by organophosphates and divalent metal ions, but less so by EDTA or pCMB (Lawrence et al., 1967). 

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

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. 

Figure 11.8. Pathways for the catabolism of free fatty acids in cheese during ripening (reprinted from Cheese Chemistry, Physics and Microbiology, 3rd edn P.F. Fox et al. (eds.), Collins, Y.F., McSweeney, P.L.H., Wilkinson, M.G., Lipolysis and Catabolism of fatty acids in cheese, pp. 373-379, 2004, with permission from Elsevier).

Contarini, G., Toppino, P.M. 1995. Lipolysis in Gorgonzola cheese during ripening. Int. Dairy J. 5, 141-155. 

High-pressure-induced biochemical aspects such as glycolysis, lipolysis, and proteolysis during ripening of cheese have been studied by a number of researchers. Yokohama et al. (1992) showed that high-pressure treatment resulted in considerable reduction in the ripening time due to proteolysis of milk protein, which resulted in an increase in free amino acids content and improvement in taste. The increased free amino acids content, from 21.3 to 26.5 mg/g, in cheese treated at 50 MPa for 3 days was comparable to 6-month old control cheese. 

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. 

The principal features of the primary biochemical events in ripening, especially glycolysis and lipolysis, are well established. Proteolysis, especially in long-ripened cheeses, is much more complex than glycolysis and lipolysis the initial proteolytic events are now well established and the great diversity of peptides and the enzymes that produce them are now being elucidated. It appears reasonable to predict that the proteolytic diversity, pathways, and kinetics in the principal cheese varieties will be established during the next 5-10 years. 

Fontecha, J., Mayo, I., Toledano, G., and Juarez, M. Use of changes in triacylglycerols during ripening of cheeses with high lipolysis levels for detection of milk fat authenticity. International Dairy Journal, 16(12), 1498-1504. 2006. 

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