الفهرس 
Immobilization of rennetOnly 14 pages are availabe for public view
 |  | from | 193 |  |  |
| | | from | 193 | | |
Abstract
In part III of the present study , local commercial liquid rennets ( 13 samples ) were collected and analysed during storage and sodium chloride and calcium chloride were also determined . Moreover, imported calf rennet and its substitutes were analysed and their stabilities as affected by some factors were determined . The attained results can be summarized in the following sections : Section A : 1- Local market liquid rennets ( LMLR ) showed a wide rage of variation 2- Storage of LMLR at room temperature had a pronounced effect on decreasing the number of RUlmI and tlie normality of the tested rennets . All remets completely lost their strengtli aRer 6 mo of storage . 3- Storage of LMLR in refrigerator caused less changes comparing with storage at room temperature . 4- Sodium chloride content ranged from 6 - 14 %with an average of 10.46 + 0.67 , whereas calcium chloride content ranged from 0.05 0.35% with an average of 0.2 k 0.03% . Section B : Milk clotting of HALA ( calf rennet ) , HhBO ( bovine rennet ) and Hannilase ( microbial rennet ) was determined as affected by changing pH , temperature , calcium chloride coatent and sodiuru clllol-idc content of cow’s milk . Curd tension and curd syneresis wcre also takcn 1 - Hamilase showed the highest values of milk clotting time ( MCT ) at any given pH comparing with HALA and HABO rennets . 2- At pH 6.6 HABO rennet showed higher MCT than HALA rennet and the opposite was observed at lower pH values . 3- A pronounced decrease in MCT was recorded with decreasing the milk pH in case of all coagulants studied . 4- Generally , 1-1a1111ilasscl iowcd thc higllcst scilsilivity to heal tscallncllts than HALA and HAl3O . MCT gradually decreased in case of Hannilasc and increased in case of HABO with increasing heating temperature from 3 5 to 50 OC . 5- At 55 OC , milk was not clotted by HABO up to 90 min. , whereas MCT in case of HALA increased and in case of Hannilase decreased . 6- Calcium chloridc showcd an enhat~cinge Eecl on MCT with a similar ratc wllc~ld ill’cscnt coagul:~~~wtcsr c used . 7- Sodium chloride had a retarding effect on MCT in all cases . Hannilase showed the highest sensitivity towards NaCl concentration higher than 7.5 % . 8- HALA rennet gave the highest curd tension followed by HABO and >Hannilase . The recorded averages in (g) were 57.19 + 2.38 ,52.75 + 1.2 1 and 48.13 rt 2.28 respectively . 9- The rate of curd syr~ercsis was higllr in casc of1-IALA followcd by HABO and Hannilase in order . The recorded averages of amount of whey (g) exuded fkom 15 (g) CLU-adf ter 120 min. were 8.79 + 0.19 , 8.74 + 0.21 and 8.1 + 0.47 respectively . 10- Statistically , sensitivity of the three coagulants towards milk pH and temperature were highly significant and insignificant respectively and towards calcium cldoride and sodium cldoride were significant and insignificant in ordcr . ,The differences in curd tension values werc highly sigi~ifica~a~ndt were significant with respect to curd syneresis of the resultant curd .