Short-chain lipid species

The profile is characterized by substantial amounts of dicarboxylic acids, mainly formed in the oxidation of polyunsaturated Cl8 acids (linoleic acid, 08 2 and linolenic acid, 08 3), which are no longer detected after ageing. The presence of short chain dicarboxylic acid, and in particular of oxalic acid, is also characteristic of aged lipid layers. Moreover, in the 30 35 min interval, several peaks are detected and attributed to oxidized species of unsaturated 08 acids. Figure 7.7 reports the mass spectrum of the peak at 31.84, attributed to 13-OH-9-octadecenoic acid or 14-OH-9-octadecenoic acid. Its... 

Homstein and Crowe 18) and others (79-27) suggested that, while the fat portion of muscle foods from different species contributes to the unique flavor that characterizes the meat from these species, the lean portion of meat contributes to the basic meaty flavor thought to be identical in beef, pork, and lamb. The major differences in flavor between pork and lamb result from differences in a number of short chain unsaturated fatty acids that are not present in beef. Even though more than 600 volatile compounds have been identified from cooked beef, not one single compound has been identified to date that can be attributed to the aroma of "cooked beef." Therefore, a thorough understanding of the effect of storage on beef flavor and on lipid volatile production would be helpful to maintain or expand that portion of the beef market. 

The hpid composition of species isolated from several Didemnidae does not demonstrate any great difference from that of cyanobacteria, in particular the short-chain fatty adds (C14-C16) are in the majority. On the other hand, for the polar lipids it was noted that the relative contents of monogalactosyldiacylglycerol (MGDG) and digalactosyl-diacylglycerol (DGDG) are appredably higher in Prochloron than in cyanobacteria and other plants (Johns et al., 1981 Murata and Sato, 1983 Kendrick, Deane, and Bishop, 1984). 

These short-lived species, in turn, promote the propagation of chain peroxidation of membrane lipids, thus disrupting the cellular integrity, or they may oxidize also various xenobiotics that are in the vicinity. Indeed, the hydroperoxide dependent oxidation process has been implicated as one of the mechanisms of conversion of procarcinogens to carcinogens (6,9) ... 

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