الفهرس 
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Abstract
Cheese manufacture is now a capital intensive
industry which benefits from a high rate of turnover
and the running costs and interest changes involved
in cheese storage represent a significant proportion
of the total cost of converting milk into cheese.
Many researches have directed their work to accelerate
the ripening of cheese to achieve a great
economic profite. This include the use of proteolytic
and lipolytic enzymes. ”fhis investigat
ion was carried out to asses information on the
possibility of preparing a cheap commercial preparation
from the cattle pancreas and using this pancreatic
extract in acceleration of Domiati cheese
ripening.
The investigation was carried out in two parts:
Part I: In the first part the ~xtraction, of pancreatic
enzymes and the effect of storage on the pancreatic
preparations was studied.
The results can be summarized as follows:
1. The proteolytic and lipolytic activity of pancreactic
extract showed the maximum units by
using an extract solution of 0.5% sodium
benzoate + 2% boric acid after shaking inte~val
of 3 h.
2. The optimum pH was found to be 7-7.5 at 37°C during
the extraction of pancreas enzymes.
3. The concentration of 1% sodium chloride was found
as the most suitable for extraction and activation
of the pancreatic enzymes.
4. The effect of adding preservatives on the enzyme
activities and on the bacteriological quality of
pancreatic extract during storage was studied.
The preservatives used were benzoic, propoinic
acid, potassium sorbate and nitrite.
5. Some methods for preparing pancreatic powder were
suggested e.g. salt drying, precipitation drying,
acetone drying and lyophilization drying.
6. The salting method for powder preparation achieved
the highest total proteolytic and lipolytic activities
when expressed as specific activity;
followed by the lyophili~ed drying; aceteone
powder; and the last one was the precipitated
drying.
7. The proteolytic and lipolytic activities of the
different forms of powder showed variable percentages
of decrease during storage at room
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temperature, but the salted dried form showed the
least percentage in decrease.
8. The bacteriological quality of the different forms
of powder revealed that the lyophilized powder had
the highest count of bacteria while the salt dried
powder showed the least counts of bacteria.
Part II: In the second part, the pancreatic extract
was used as an agent for accelerating Domiati
cheese ripening. Different concentrations of the
extract 0, 2.5, 5.0, 7.5 and 10 ml/lO Kg milk)
were added to the cheese milk.
The results of this part were as follows:
1. Addition of pancreatic extract had an insignificant
effect on moisture and salt content while it decreased
fat content and pH value and total nitrogen.
2. All the ripening indices of the cheese pointed that
the addition of pancreatic extract accelerated the
cheese ripening as the differences between treatments
were significant.
3. The electrophoretic pattern showed that the breakdown
of protein during ripening was higher in the
treated milk cheese than untreated cheese.
o
4. Quantitative changes in free fatty acids and free
amino acids occurred during the ripening were discussed.
5. Scoring of cheese indicates that cheese made from
treated milk proceeds more rapid ripening than
that made without additives as it had a smooth,
creamy body with a best flavour.