Tanzania Journal of Agricultural Sciences 2001, Vol. 4(2) : 55-64
The cheese making quality of pepsin extracted from adult cattle abomasa using dilute HCI (HP) and commercial vinegar (VP) was assessed using three types of cheeses namely Alpine, Tilister and Pastafilata (Pasta). The level of each extract was substituted with commercial calf rennet (CR) at 0, 25, 50, 75, 100%. Renneting time (RT) for cheese milk butterfat (%BF) and total nitrogen (%TN) losses in whey were assessed. Chemical composition and microbial quality of cheese samples obtained at different storage time intervals and their sensory quality at maturity were determined, RT and TN losses in Alpine cheses increased with increasing levels of pepsin from 41min and 0.49% in 25% pepsin to 58min, and 0.55% in 100% pepsin (HP) respectively, Chemical composition of all cheese types with different levels of HP and VP were significantly different (p <.01) and were related to the levels of pepsin, The pH in Pasta and Alpine and % TN in Tilster cheese were not significantly different for the different level of HP and VP. Microbial counts in Alpine cheeses were not significantly different (p>0.05). Coliform and yeast/mould counts in Tilster and Pasta cheeses were not significantly different while the Standard Plate Counts (SPC) in Tilster, and Pasta cheeses were significantly different. Sensory quality was not significantly different for smell and taste. However, bitterness in Pasta and appearance in Alpine and Pasta were significantly different (P < 0.05), between enzyme combinations. Bitterness and taste in Alpine and bitternes in Tilister cheeses were significantly diffirent (p < .00l) betweern levels of HP and VP. Overall quality assesment of all cheeses did not show significant differences (p > 0.05) between levels of pepsin and types of extraction media for pepsin. HCI and vinegar extracted pepsin waa an apprqpriate renner substitute for the small scale cheese processors.