This study was conducted to investigate the effects of adding different levels of commercial pregastric lipase enzyme (calf lipase) on the free fatty acid profile of ultrafiltered Feta type cheese during ripening period. With an increase in added lipase level and ripening period, the main components of cheese including total solids, fat, fat in total solids, salt and salt in total solids did not change significantly but water soluble nitrogen increased. Increasing the added pregastric lipase level resulted in a significant decrease in the percentages of C4:0-C8:0 free fatty acids while that of C12:0-C18:0 and C18:1 free fatty acids increased. According to sensory analysis of cheese samples, the best samples had the combination of 20, 40 and 60 days of ripening with 6 g/100 kg, 4 g/100 kg and 2 g/100 kg lipase in retentate, respectively. The addition of lipase to cheese milk could be recommended for the acceleration of flavor development and ripening of UF-Feta cheese over a short ripening period.
