Ripening

Flavour and texture in Cheddar cheese develops over extended maturation period. Proteolysis is the most extensive biochemical event occurring during ripening and, in contrast, lipolysis is limited. In mature Cheddar, approximately 25% of the total nitrogen is soluble in water and small peptides and amino acids, which contribute to flavour, generally participate into this fraction.

The starter lactic acid bacteria make a significant contribution to cheese proteolysis.The proteolytic activity of the NSLAB supplements that of starter producing peptides with similar molecular weights to those produced by the starter culture and also amino acids.

i. Amino Acid Catabolism: The free amino acids generated as a result of proteolysis may be catabolized by the starter lactic acid bacteria and NSLAB to flavourful compounds such as aldehydes, alcohols, esters and thiols. As the final flavour of cheese depends on the respective concentration of different key aroma compounds, the control of amino acid degradation during cheese ripening appears to be a potential means of manipulating the flavour profile of Cheddar.

ii. Textural Characteristics: Freshly pressed Cheddar cheese comprises a casein matrix interspersed with fat globules and water. The cheddaring process leads to the formation of a fibrous protein network that produces a very close – textured Cheddar cheese. The relative levels of fat, protein and moisture affect the rheological properties of the curd and the rate of texture development is associated with the degradation of the casein. Within the first 7-14 days,residual coagulant enzymes are responsible for the rapid hydrolysis of the ás1- casein to soluble peptides and this causes mellowing of the rubbery elastic texture.

iii. Taste and Aroma: Cheddar flavour is not associated with one potent chemical compound but appears to result from the generation of number of components during ripening. The production of cheese flavour compounds must be balanced and excessive production of individual components leads to generation of offflavours.The taste of Cheddar is associated with the water-soluble nonvolatile fraction.This is comprised of small and medium-sized peptides, free amino acids, organic acids and their salts. Peptides and amino acids contribute to the background savoury flavour of Cheddar, while specific peptides can impart undesirable bitter flavours. Volatile aroma compounds have the potential to add the specific flavour notes to Cheddar. These are mainly derived from proteolysis but also from lipolysis.