الفهرس 
Material and methodsOnly 14 pages are availabe for public view
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Abstract
SUMMARY AND CONCLUSION
Due to the economical importance of accelerating the
ripening of cheese, a great deal of attention has been
given in this respect.
Characterization of the unique properties of various
lipolytic enzymes. and recognition of the flavour potential
of milk fat, resulting from its characteristic composition
of short chain fatty acids, have led to the development of
numerous applications of controlled lipolysis for flavour
development. The acceleration of flavour in several cheese
varieties have been achieved by the direct addition of
lipolytic enzymes to cheese milk. Moreover this investigation
was carried out to asses information on the possibility . of using lipase enzyme in accelerating the ripening of
Domiati cheese made from buffaloes’ milk and its effect on
the quality and composition of the cheese.
The investigation was carried out in two parts:
Part I: In the first part the effect of adding different
concentrations of lipase enzyme (0, 8. 10 and 12 gm/100 kg
milk) to buffaloes’ milk before renneting during the manufacture
of Domiati cheese was studied.
The results can be summarized as follows:
1. Effect of a~ding different concentrations of lipase
enzyme on moisture, fat and salt was not apparent. However
cheeses with the largest quantity of added enzyme was
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characterized by slightly high moisture content and a
slight decrease in the fat content.
2. The addition of lipase to cheese milk had an
apparent increase in the aCidity of cheese.
3. The T.N. in cheese increased during the first
month then slightly decreased during the rest period of
storage. The addition of lipase increased the T.N. per
dry matter.
4. The addition of lipase caused a slight difference
in soluble nitrogen and ripening indicies.
5. The addition of lipase enhanced the development of
V.F.A. also the T.V.F.A. increased with advanced storage.
6. The cheese fat acidity ran parallel to T.V.F.A.
being progressively increased with storage and added lipase
as a result of fat hydrolysis by the action of lipase
enzyme.
7. The addition of lipase enzyme was found to ehnahce
the development of cheese flavour after 30 days of storage.
Excellent flavour and highly acceptable consistency were
observed. However, rancid flavour was detected in cheese
with high amount of lipase (12 gm lipase/lOO kg milk) after
90 days. It could __ concluded that the addition of lipase
at a level of 10 g_ lipase/IOO kg milk proceeds more rapid
ripening with a s_oath body and a good flavour and ranked
the best.
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8. The average percent cheese yield of the control
was slightly lower than that with added lipase all through
the storage.
Part II. In the second part, the lipase enzyme was added
during the manufacture of Domiati cheese with a level of
10 gm/IOO kg milk by three different methods, being, on
cheese milk before renneting, on the cream to be lipolyzed
then added to its skim milk before renneti~g and the third
method was the addition of lipase on the curd after coagulation.
The results of this part were as follows:
1. Cheese with lipolyzed cream was characterized by
low moisture and salt content and. pH value than the other
treatments.
2. The lipolyzed cream cheese had a high fat content,
titratable acidity and proteolytic products (soluble nitrogen,
soluble tyrosine and tryptophan and formol index) but a slight
decrease in total nitrogen than the other treatments.
3. The T.V.F.A. and cheese fat aCidity in cheese made
with lipase treated cream was higher than those of the two
other methods.
4. It is evident that the yield of lipolyzed cream
cheese was lower th~ the two types of cheese.
5. Lipolyzed cream treatment was considered the best
one due to its suit~le odour, texture and smooth body than
the other treatments.