EFFECT OF ADDING MICROBIAL LIPASE ON THE ACCELERATION OF UF-RAS CHEESE RIPENING

Abstract

The effect of adding microbial lipase enzyme to UF cheese milk (0, 50.000, 100.000, and 150.000 lipase units/15kg retentate) on some chemical, rheological, and sensory characteristics of UF-Ras cheese was studied during the 3 months of ripening. The obtained results indicated that lipase enzyme caused a little effect on the gross composition of cheese during ripening. The level of lipolysis and proteolysis were significantly (p < 0.05) higher in the experimental cheeses than those of the control cheese during ripening, which means that there are a positive effect of lipase on ripening time.Lipase addition led to increase the rate of liploysis process about 30 % in 60 days and treated cheeses of this age had TVFA levels typical of 90 days of untreated cheeses. Moreover, enzyme-treated cheese had harder texture than untreated cheeses of the same age. Sensory evaluation showed a significant difference in the total scores of the experimental and control cheeses, with significantly lower-quality scores for the cheeses treated with 100.000 and 150.000 u/15 kg retentate. Cheeses with the highest level of lipase pronounced bitter taste at 60 days of ripening. The most acceptable cheeses were the UF Ras cheese treated with lipase 50.000U/15 kg retentate, which was a slightly similar to the control cheeses at 60 days of ripening.