Short-chain volatile FFAs

Milk fat contains a number of different lipids, but is predominately made up of triacylglycerols (TAG) (98%). The remaining lipids are diacylglycerols (DAG), monoacylglycerols (MAG), phospholipids, free fatty acids (FFA) and sterols. Milk fat contains over 250 different fatty acids, but 15 of these make up approximately 95% of the total (Banks, 1991) the most important are shown in Table 19.1. The unique aspect of bovine, ovine and caprine milk fat, in comparison to vegetable oils, is the presence of high levels of short-chain volatile FFAs (SCFFA), which have a major impact on the flavor/aroma of dairy products. Most cheeses are produced from either bovine, ovine or caprine milk and the differences of their FFA profile are responsible for the characteristic flavor of cheeses produced from such milks (Ha and Lindsay, 1991). 

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. 

Improvement of the deodorizer design by the installation of baffles and demisters in the vapor chimneys has significantly reduced entrainment losses to 0.1-0.2% in chemical refining. For steam refining, an additional loss directly proportional to the FFA content has to be taken into account. For most oils (soybean oil, pahn oil, etc.), NOL is exclusively due to mechanical carry-over. However, in lauric oils, part of the NOL is a consequence of effective evaporation of volatile short-chain mono- and diacylglycerols (30). (Table 13). This distillation loss of NOL is inherently due to the deodorization conditions, but is not affected by the deodorizer design. 

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