Biochemistry of Cheese Ripening

Lipolysis and sensory characteristics of Cheddar cheeses ripened using different temperature-time treatments

“…It is interesting to note that, on increasing ripening temperature from that of treatment A (4°C) to that of treatment G (12°C), the greatest difference in FFA levels at 60 d of ripening was for the short-chain FFA (Σ(C 4:0 -C 8:0 )). This is an important observation, as shortchain FFA have low flavour thresholds [3] and have the propensity to contribute directly to Cheddar cheese flavour or can act as precursors for important flavour compounds (e.g., methyl ketones) once liberated [20,38]. Increasing ripening temperature from 4 to 8°C had little impact on FFA levels, while, an increase in ripening temperature of the same magnitude, from 8 to 12°C, resulted in a much faster rate of accumulation of FFA in the cheeses during ripening.…”

“…Thus, the increase in total FFA levels on increasing ripening temperature from 8 to 12°C was due to increases in the levels of FFA within each of the short-medium-and longchain FFA classes; however, the greatest relative increase was again observed for short-chain FFA. FFA are important in generating the flavour and aroma of many cheese varieties [20,37,38,63] and have been reported to contribute to the flavour and aroma of Cheddar cheese [3,17,18,50].…”

“…Cheese ripening involves a concerted series of microbiological, chemical and biochemical reactions that are ultimately responsible for the development of characteristic texture, flavour, aroma and appearance of individual cheese varieties [20]. Cheese flavour is extremely complex and is best explained by the "Component Balance Theory" [42], which proposes that cheese flavour is due to the interaction, in correct proportions, of many compounds, present at specific concentrations.…”

“…There are three primary routes by which biochemical activity proceeds in cheese during ripening; namely, proteolysis, lipolysis and the metabolism of residual lactose and of lactate and citrate [37]. The relative importance of each of these processes is largely dependant on cheese variety; however, proteolysis is believed to be the most complex, and to play a significant role in the ripening of nearly all varieties [20]. This is especially true in internal bacterially-ripened (e.g., Cheddar) and smear-ripened cheeses (e.g., Tilsit), in which it is considered the main biochemical event [57].…”

“…Ripening of Cheddar cheese is largely an enzymatic process [19] with the principal lipolytic enzymes in Cheddar cheese curd made from pasteurised milk reported to be lipases and esterases of lactic acid bacteria (LAB) [3,25]. The activity of such enzymes is generally accepted as being weak or limited, especially towards triglyceride substrates [2,20,24,54,56]. The contribution of the indigenous milk lipoprotein lipase (LPL) to liberation of free fatty acids in maturing Cheddar cheese is limited, as it is largely inactivated by pasteurisation [6,7].…”