End of Project ReportThere is a poor understanding of
the relationship between organoleptic assessment of cheese and quantitative
analysis of flavour compounds. Further, the contribution of particular cheese-making parameters such as ripening temperature and starter culture has not been
fully elucidated.
During the ripening of most cheese varieties complex chemical conversions occur within the
cheese matrix. In most cheese varieties breakdown of protein is the most important flavour
development pathway. The primary cheese protein, casein, is degraded enzymatically to
short peptides and free amino acids. The agents primarily responsible for these conversions
are the residual rennet that is retained in the cheese curd at the end of the manufacturing
phase and the proteinases and peptidases that are associated with the starter bacteria. While
the rate and degree of proteolysis are of vital significance for desired flavour development,
the direct products of proteolysis do not fully define cheese flavour. Much research is now
demonstrating that the further biochemical and chemical conversions of the products of
proteolysis, in particular the amino acids, are necessary for full flavour development. The
products produced by these pathways are volatile at low boiling points and are thus
released during mastication of the cheese in the mouth. Many of these volatile compounds
contribute to the flavour sensation experienced by the consumer. A very wide spectrum of
such compounds have been isolated from cheese, in excess of two hundred in some cheese
varieties. It is now generally accepted that there is no individual compound which defines
cheese flavour completely and that the flavour sensation is the result of numerous
compounds present in the correct proportions. This has become known as the Component
Balance Theory .
The application of modern analytical techniques as proposed in this project would provide
a greater understanding of the significant flavour compounds in Cheddar cheese and help
to identify the impact of specific cheese-making parameters such as starter flora and
ripening temperature on the production of volatile flavour compounds. This data would
assist the general programme on flavour improvement of cheese which should ultimately
benefit the cheese manufacturer.
Hence this project set out to develop methods to identify the key flavour compounds in
Cheddar cheese. These techniques would then be applied to experimental and commercial
cheeses during ripening in an effort to identify key compounds and the influence of starter
cultures and ripening temperature on their production.Department of Agriculture, Food and the Marin
