Changes in the volatile flavour components of Jinhua ham during the traditional ageing process

Changes in volatile flavour compounds of Jinhua ham were studied during the traditional ageing process of sun-drying, loft-ageing and post-ageing. About seventy-eight volatile compounds were tentatively identified, including aldehydes (ten to fifteen), carboxylic acids (eight to ten), alcohols (thirteen to fourteen), ketones (eight), esters (eight to ten), aromatic hydrocarbons (five), sulphur-containing compounds (two to three) and pyrazines (zero to four) which were the main components. The percentage content of aldehydes and ketones reduced over time as the temperature rose with each stage of the process, whereas alcohols, carboxylic acids, esters, pyrazines and sulphur-containing compounds increased gradually. Jinhua ham's high-temperature maturating process (40 days at 30-37 degrees C) made the percentage content of carboxylic acids arising from Maillard reactions markedly increase (from sun-dried ham 8.45% to fully aged ham 19.23%). This was the most obvious difference between Jinhua ham and the Mediterranean dry-cured hams, and was the main factor leading to the unique flavour of Jinhua ham.