Effect of modifying lactose concentration in cheese curd on proteolysis and in quality of Cheddar cheese

Cheddar cheese was manufactured on two occasions from three 100kg batches of milk: control (C), lactose-reduced cheese (L) prepared by removing some whey and replacing it by warm (40°C) and lactose-enriched cheese (H) made from milk supplemented with lactose to 8.4% lactose in cheese milk. L-cheeses were almost free of lactose within 60 days of ripening compared to 150 days for C cheeses; the H cheese contained 1.4% lactose after 180 days. The pH of the C and L cheeses remained almost constant throughout ripening, while that of the H cheeses decreased continuously. Modification of the lactose content had little effect on gross composition, primary proteolysis or the numbers of starter and non-starter bacteria in the cheeses. The H and L cheeses had the lowest and highest total concentration of amino acids after 180 days of ripening. Commercial graders considered the L cheese to be very immature up to 4 months of age but 180 day-old L cheese was awarded flavour scores similar to C cheese. The 180 day-old H cheese received the lowest flavour scores. A 14-member sensory panel reported that L cheese had a significantly lower flavour intensity, a less sour/acid flavour, was less firm and crumbly but had better mouth-coating properties than the control or H cheese.