الفهرس 
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Abstract
Soybeans is one of the most important crops for humman feeding as it contains a high protein content which accounts for about 35 - 38%. Soymilk represents an inexpensive and aboundant source of good protein quality, that could be the best choice to replace or extended the dairy products, to reduce their price and achieve the nutritions and healthy properties.
The aim of the present work was to study the posibility of using soymilk for OF Feta-like cheese making from a mixture of milk and soymilk in rate of 2:1, with the using of starter culture from 1 to 3% containing 25% or 50% probiotic bacteria (Bifidobacterium locus Bb 12).
The produced cheeses were more acceptable than the control either that made from milk or from soy milk and more effective in lowering the total cholesterol, LDL-cholesterol and triglycerides.
The results of our investigation have been presented and discussed in two main parts as follows:
Part 1:
Section 1: Preparation and chemical properties of soymilk In this section, the soymilk was prepared from soybean seeds and the chemical composition was studied. The obtained results cleared that:
1-preparation of soymilk reduced the antinutrational factors of soybean and soymilk like, trypsin inhibator, phytic acid and urease activity.
2-A slight increase in protein, ash and fat%. Also, a slight decrease was recorded in moisture, fibers and carbohydrates%.
3-The mixture of milk and soymilk with ratio of 2:1 reflect a slight increase in protein and carbohydrate, however a slight decrease was noticed in moisture,ash, and fat compared with milk
Section 2: Production and properties of probiotic OF Feta-like cheese made from mixture of milk and soymilk (2:1).
In this section the mixture of milk and soymilk 2:1 was concentrated by ultrafiltration technique up to -28% total solids. The final concentrate was then heated to 75°C for 2 min., cooled to 40°C and then devided into two parts. The first one was treated with 1, 2 and 3% mixed starter containig 50% Bifidobacterium lactis Bb12 + 50% Lb. casei sub spp. casei + L. lactis sub spp. lactis + L. lactis sub spp. cremoris (1:1:1).
The second part was treated with 1, 2 and 3% mixed starter containing 25% Bifidobacterium lactis Bb12 + 75% Lb. casei sub sub spp. casei + L. lactis sub spp. lactis + L. lactis sub spp. cremoris (1:1:1).
The control cheese of soymilk or whole milk were only treated with 1% mixed starter containing Lb. casei sub spp. casei + L. lactis sub spp. lactis + L. lactis sub spp. cremoris (1:1:1) without Bifidobacterium.
The cheese of different treatments were made as described under materials and methods and were analyzed when fresh and after 15 days intervals up to 45 days for organoleptic,chemical and microbiological properties.
The obtained results can be summarized as follows:
1.The chemical composition, namely, moisture, fat, salt and total nitrogen contents of all cheese samples were not significantly affected for different treatments and the slight effect was due to the lowering of moisture content.
2.The moisture content of all cheese treatments were gradually decrased all over the storage period. The acidity was gradually increased by advancing the storage. The acid development was proportional to the percentages of the added starter to retentate during cheese preparation.
On the other hand. T3 and T6 recorded the highest acidity during the storage.
3.The ripening indices of the cheese samples showed that the protein and fat breakdown were proportional to the percentages of starters added containing 50% Bifidobacterium lactis Bb12. The increase of soluble nitrogen, SN/TN, soluble tyrosein, tryptophan and total volatile fatty acids indicating an increase of ripening during storage. Treatment 3 and 6 (treated with 3% starter of 50% or 25% Bifidobacterium lactis Bb12 + 50% or 75% mixed lactic starter respectively) recorded the highest ripening indices compared with the control.
4.The sensory evaluation for the produced cheese showed that treatment 3 and 6were the best treatments. This was a reflection of the mixing of both soymilk and Bifidobacterium lactis Bb12.
5.The firmness of all cheeses were increased gradually by increasing the storage period in all treatments compared with soy cheese (control T8).
6.The microbiological examination of all cheese samples recorded an increase of total bacteria count, lipolytic bacteria, protyoletic bacterial and Bifidobacteria count at the beginning of the storage period compared with control treatments. At the end of storage their was a gradual decrease. The coliforms were not detected all over the storage period in all treatments. The mould and yeasts were absent at the beginning and till 15 days of storage however they were detected at the end of the storage period.
Part II:
Section 1: The Hypocholesterolemic effect of the probiotic and UF Feta-like cheese on rats fed on cholesterol enriched diet:
This part of the study aimed to explore some of the health promoting effect of probiotic UF Feta - like cheese with regard to their potential role in lowing the cholesterol by feeding the rats on cholesterol-enriched diet containing probiotic UF soy Feta - like cheese .
The results could be summarized as follow:
1)The beginning period of feeding showed a significant differances between negative group and other groups in total cholesterol level, triglycerides, HDL-cholesterol and VLDL + LDL -cholesterol levels .
2)The groups of rats which fed on T3 and T6 recorded the highest lowring in total cholesterol level .
3)The triglyceride level showed a significant defferance of decrerase in all groups of UF Feta-like cheese and the lowest level recroded in T3 .
4)The HDL-cholesterol level decreased up to the end of the forth week all of groups fed on UF Feta-like cheese treatment, but at the end of 6 weeks the level of HDL-cholesterol increased.
5)The (VLDL+ LDL)-cholesterol level gradually increased up to 4 weeks then it decreased at the end of 6 weeks which recorded the lowest level compared with its content at the first week .
Section 2: Histopathological profile of rats fed on cholesterol-enriched diet as a functional of
probitic OF feta-like cheese:
•Group (1) : Fed on basal diet (negative control). The organs showed no significant changes.
•Group (2) : Fed on basal diet + 0.5% cholesterol (positive control) Kidney, liver and heart had a degenerative changes in the reval tissues. Cloudy swelling in the tubular epithlium which showed intracytoplasmic and some glomurli fregmentation of the tuft and replaced by basophilic calafied mass, degenerative changes in the hepotocytes include vacular & hydrobicdegeneration with pole acidophilic. Cutoplasm and Hyaline degredation in the cardiac muscles, intermuscular hemorrhage were recorded in the blood vessels respectively .
•Group 3 — 8 (treated groups): Fed on 0.5% cholesterol + deferent treatments from 3 to 8 supplemented with (10% casein, 10% fat) basal diet:
•Some histopathological changes were recorded in the reual tissue of the kidney include, cloudy swelling in the reual epthelium, with intracytoplasmic eosiuphilic granules with storshape lumen. In the liver mild degeneration changes in the pareuchyma in the forum of hydrobic degeneration with pyknotic nuclei, congestion in the portal bloodvessels with mild mononuclear cellulor infiltration. But non significant changes were recorded in the heart.
•Group 9 : Fed on 0.5% cholesterol + treatment 7 supplemented with (10% casein, 10%fat) basal diet :
Mild degenerative changes in the forum eosinophilic substance in the lumen of the tubules of kidney , also some of the loumurli showed destruction and others showed shrinkage. In the liver, the hepatocytes
showed vacuolotion & the central vein showed diltation. But the cardioc muscle of heart showed non-significant histopathological changes.
•Group 10 : Fed on 0.5% colesterol + treatment 8 supplemented with (10% casein, 10 % fat) basal diet : the histopathological changes of kidney were mild, only represented by desauamation of the liuing epithdium of the reual tubules with some destruction of few glomurli. The degenerative changes of liver were present as that of previous group, only a new finding represented by severe congestion of the blood vessels. Finly mild intermuscular edema of heart, also intermuscular cangestion of some blood vessel were recorded in same microscopic observation.
from the preivious study it could be concluded that
•Prepared soy milk by previous described method to obtained soy milk with good quality and characteristics.
•Soy milk can be used with milk up to 28% total solids in making UF Feta-like cheese without any affects on the cheese characteristics which supplemented with Bifidobacterium lactis Bb 12 + Lactic culture (Lb. casei sub spp. casei + L. lactis sub spp. lactis + L. lactis sub spp. cremoris 1:1:1) at ratio of 3%
•Producing UF Feta-like cheese from healthy propertries by adding 3% from starter culture containing 50% Bifidobacterium lactis Bb 12 + 50% Lactic culture (Lb. casei sub spp. casei + L. lactis sub spp. lactis + L. lactis sub spp. cremoris 1:1:1).
•The produced cheese lowerd the serum of total cholesterol level in the rats blood which fed on cholesterol-enriched diet.