ABSTRACT
The present study aimed to isolate calf rennet, bovine, and chicken
pepsin enzymes from different sources, purified and immobilized on
paraffin and honey waxes mixture (1:1, w/w) to use in white soft cheese
making as well as to compare it with the corresponding ones of free
coagulant enzymes. The enzymes were extracted from the stomach of three
different sources (big bovine stomach tissues, chicken gizzard and calf
abomasum tissues). White soft Cheeses were made from standardized cow's
milk (%3.64 fat) using the former coagulants either free or immobilized.
Cheese was stored at room temperature for 1, 30, 60, and 90 days.
Results indicated that cheese made using free enzymes had higher
values of yield, moisture, and titratable acidity and lower values of protein
compared with that made using immobilized enzymes. Cheese made using
free coagulant enzymes had, also, higher values of cheese ripening indices
and total volatile fatty acids. On the other hand cheeses made with bovine
and chicken enzymes had higher initial cheese ripening indices than the calf
rennet cheeses, during the storage period. All cheeses showed gradual loss
of yield, moisture, and pH values during storage while, protein, fat and
titratable acidity were increased in both immobilized or free enzymes
cheeses. Gradual increase in cheese ripening indices and total volatile free
fatty acids (TVFFAs) contents were noticed in all treatments, during 90 days
of ripening. Retained enzymes were found lower in cheese curds made
using immobilized enzymes and higher in whey of cheese made using free
ones. Organoleptic evaluation revealed that cheeses of calf rennet, either
free or immobilized, were slightly prefered organoleptically, all over the
storage period, than the other cheeses contained bovine or chicken pepsins.
Calf rennet cheeses were characterized by clean flavor, firm and good body
and texture. Bovine pepsin cheeses exhibit slightly bitter taste and to
somewhat friable body and texture at the end of the storage period.
Generally, no obvious differences were observed between free coagulant
enzymes and immobilized ones, through the storage period and all the
resultant cheeses were accetptable .This study demonstrated the beneficial
effect of using the immobilization technique for cheese making to reduce the
Egypt. J. of Appl. Sci., 36 (7-8) 2021 29-44
cost of production , by reusing the immobilized enzymes several times ,
compensation the shortage of animal coagulants (especially in calf rennet)
and maintenance the quality of the resultant soft cheese.