Biochemical pathways for the production of flavour compounds in cheeses during ripening: A review

The principal pathways for the formation of flavour compounds in cheese (gl ycolysis, lipolysis and proteolysis) are reviewed. Depending on variety, mi croflora and ripening conditions, lactate may be metabolized by a number of pathways to various compounds which contribute to cheese flavour or off-fl avours. Citrate metabolism by citrate-positive lactococci or Leuconostoc sp p. is important in certain varieties (e.g., Dutch cheeses). Lipolysis resul ts directly in the formation of flavour compounds by liberating free fatty acids (FFA). FFA may also be metabolized to alkan-2-ones and fatty acid lac tones. Proteolysis of the caseins to a range of small- and intermediate-siz ed peptides and free amino acids (FAA) probably only contributes to the bac kground flavour of most cheese varieties, but FAA are important precursors for a range of poorly-understood catabolic reactions which produce volatile compounds essential for flavour.