Production of fat-derived (flavour) compounds during the ripening of Gouda cheese

Fat-derived flavour compounds in four different batches of Gouda cheese were monitored over 2 years of ripening. The total free fatty acid (FFA) concentrations increased from 200-400 to 700-1200 mg kg-1 dry matter, in a fairly linear manner. Long-chain FFAs were predominant in the curds, but relatively more short and intermediate chain fatty acids were released during ripening. The production of δ-lactones was rapid initially, but reached a plateau at 55 mg kg-1 dry matter in about 20 weeks. The production of γ-lactones was slower and also decreased, but was noticeable over a longer time, giving 5.5 mg kg-1 dry matter in 90 weeks. Ethyl ester formation varied substantially. Ketone levels increased only very slightly during ripening; long chain alcohols and aldehydes were not found. Some individual FFAs and lactones exceeded reported flavour thresholds, and are expected to influence the flavour of Gouda cheese.