conditions these will condense out of the gas to form natural gas condensate, often shortened to condensate. Condensate resembles petrol in appearance and is similar in composition to some volatile light crude oils. The proportion of light hydrocarbons in the petroleum mixture varies greatly among different oil fields, ranging from as much as 97 percent by weight in the lighter oils to as little as 50 percent in the heavier oils and bitumens. The hydrocarbons in crude oil are mostly alkanes, cycloalkanes and various aromatic hydrocarbons while the other organic compounds contain nitrogen, oxygen and sulfur, and trace amounts of metals such as iron, nickel, copper and vanadium. The exact molecular composition varies widely from formation to formation but the proportion of chemical elements vary over fairly narrow limits as follows: Composition by weight Element Percent range Carbon 83 to 87% Hydrogen 10 to 14% Nitrogen 0.1 to 2% Oxygen 0
Lipolysis, together with proteolysis, is bial compounds, such as bacteriocins and/or believed to play a central role in aroma low-molecular mass antimicrobial com- formation. This phenomena is only the first pounds, may be one of the critical character- step in the process and is followed by further istics for effective competitive exclusion. As oxidative degradation of fatty acids into mentioned above, one of the main roles of alkanes, alkenes, alcohols, aldehydes, and meat LAB starter cultures is the rapid pro- ketones (Viallon et al. 1996; Chizzolini et al. duction of organics acids; this inhibits the 1998), which enhances the development of growth of unwanted biota and enhances the flavor. In fact, medium- and long-chain product safety and shelf life. Likewise, fatty acids act as precursors of aroma com- several authors have reported the role of
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