The unique flavour of Jinhua ham is caused by enzymes that break up long-chain molecules
Jinhua ham is the most famous dry-cured meat product in China, with a history dating back over 1,100 years. It is a highly regarded ingredient used in making soup stock in Chinese cuisine because it imparts 'umami' (a unique flavour) to any dish. But why is it so tasty? Guanghong Zhou at the Nanjing Agricultural University and Gaiming Zhao at the Henan Agricultural University in Zhengzhou have found that enzymes in the ham break up proteins and lipids into more flavoursome short-chain molecules1.
To produce Jinhua ham, green ham is salted, washed, sun-dried, shaped and then left to ripen for up to eight months. During this long process several enzymes remain active. Cathepsin enzymes act on insoluble proteins to make them soluble, then other enzymes — dipeptidyl peptidases and aminopeptidases — break up the soluble proteins to produce peptides and free amino acids. This leads to free-amino-acid levels 14–16 times higher than in untreated green ham. In addition, lipase enzymes act on lipids in muscle and fat tissue to produce free fatty acids.
The break-up of proteins also produces volatile compounds in Jinhua ham, of which the researchers have identified 191 so far. At least 22 of these compounds, including aldehydes, alcohols, esters and sulphur compounds, contribute to the characteristic flavour and aroma of the ham.