الفهرس 
1.INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Ice cream is the most popular frozen dessert in Egypt and all the world, It is highly accepted by children, adults. The production and consumption of frozen desserts have been increased tremendously recently in Egypt and all over the world because of production of different forms and types, using a wide range of ingredients and flavours, using frozen desserts as a carrier for probiotics, prebiotics and nutraceuticals and finally using the frozen desserts as functional foods. .
Yoghurt is the most popular fermented dairy product in Egypt and worldwide. The value of yoghurt in human nutrition is based not only the nutritive value of the milk from which it is made and increased digestilulity and bioavailability because the chemical changes of milk constituents occurring during fermentation, but also the beneficial effects such as, prophylactic and healing effects, healing effects when antibiotic and radiation therapy applied and for people suffering from chronic constipation, diarrhea, colitis, intestinal intoxication, liver and bile disorders and better tolerating of lactose in yoghurt by individuals suffering from hypolactasia. . Dietary fiber is naturally present in cereals, vegetables, fruits and nuts. It is not digested by enzymes in the human intestinal tract, but part of it may be metabolized by bacteria in the lower gut. Dietary fibers are classified as soluble and insoluble fibers. It has crucial health benefit effects such as reducing of colon and heart related diseases, reducing diabetes incidence, gut reducing neoplasia, reducing the risk of colon cancer, preventing constipation and hemorrhoids, lowering blood cholesterol, regulating blood glucose levels for diabetes management, producing short chain fatty acids, increasing calcium absorption, stimulating the immune system and acting as prebiotics which enhance the growth of beneficial gut microflora.
Mango is one of the most cultivated fruit in the world. Mango is a seasonal fruit; therefore 20% of fruit are processed for products such as puree, nectar, juice, pickles and canned slices. Peel, which is a major by-product during processing of mango, contributes about 15-20% of the fruit. It has been reported that mango’s peel is a good source of polyphenols, carotenoids, vitamin E and C and dietary fibers Also, it exhibited good antioxidant properties. It has been reported that mango’s pulp fibers powder contain appreciable amounts of beneficial chemical and physiochemical properties and it exhibits high water and oil holding capacity and acting as a prebiotic for bifidobacteria. Dairy products are not a good source of fibers however;they could provide an alternative vehicle for the development of fibers enrich foods. .
Bifidobacteria are becoming recognized worldwide because of their health and nutritional benefits such as antitumorigenic activity improvement of lactose-tolerance, reduction of serum cholesterol levels, reduction of ammonia and free serum phenolin patients with liver disease, synthesis of vitamins, increased immune competence and antagonistic effects towards enteropathogenic bacteria. Therefore, it has been tried to incorporate these bacteria in dairy products.
In view of the aforementioned the objectives of this study were to investigate the possibility of making a good quality ice milk that supplemented with mango’s peel powder and study the effect of supplementing probiotic yoghurt with mango’s pulp fibers powder. This study has been carried out in two parts::
Part Ι:: Effect of suppllementing ice millk with mango’’s
peell powder fibers powder on its quallity::
It has been concerned in this part to investigate the effect of supplementing ice milk with mango’s peel powder fibers powder on some chemical, rheological and organoleptic properties of ice milk, therefore 5 treatments of ice milk were made. Control ice milk treatment was prepared without mango’s peel fibers powder. The other four treatments were made by adding 0.5, 1.0, 1.5, 2.0 mango’s peel fibers powder. .
All treatments were stored in the freezer for 10 weeks and were sampled at 0, 2, 4, 6, 8 and10 weeks of storage period for pH, titratible acidity and sensory evaluation and were sampled at 0, 5 and 10 weeks of storage for the other chemical and rheological properties.
The obtained resullts can be summarized as follllow::
1- Titratable acidity of ice milk mixes were not significantly different from each other which means that supplemented ice milk with mango’s peel powder fibers did have not significant effect on the titratable acidity of ice milk mixes.
2- Supplemented ice milk with mango’s peel powder fibers caused a significant increase in specific gravity and weight per gallon of ice milk mixes. This increase was proportional to the rate of supplementation with mango’s peel powder.
3- Overrun of ice milk made by supplementation with mango’s peel powder decreased slightly by increasing the rate of supplementation above 1% of mango’s peel powder, while ice milk treatments C, T1, T2 those made by adding 0.0, 0.5 and 1.0% mango’s peel powder where not significantly different from each other .
4- Supplementation of ice milk with mango’s peel powder caused a significant increase in specific gravity and weight per gallon of ice milk. This increase was proportional to the rate supplementation with mango’s peel fibers powder.
5- Supplementation of ice milk with mango’s peel powder caused a significant increase in the rate of melting resistance after 60 min and next 30 min melting resistance decrease at the last 30 min.
6- Titratable acidity and pH values of ice milk were not significantly different from each other which means that supplementation of ice milk with mango’s peel powder did have not significant effect on the titratable acidity and pH values. Titratable acidity and pH values of ice milk treatments were not significantly different during storage period.
7- Supplementation of ice milk with mango’s peel powder did not have significant effect on fat and ash content of ice milk treatments. Fat and ash content of all ice milk treatments did not change significantly during storage period.
8- Total solids and total protein of ice milk treatments made with the addition of mango’s peel powder increase significantly, while they did not change significantly during storage period.
9- Scores of flavor, body and texture, melting resistance, colour and total scores of organoleptic properties of all ice milk treatments followed similar trends. Ice milk treatments were accepted by the panelists, but the most acceptable treatment was T3 that made by adding 1.5% of mango’s peel fibres powder. Part П:: Effect of suppllementing yoghurt with mango’’s
pullp fibers powder on its quallity and the
survivall of bifidobacteria::
It has been concerned in this part to investigate the effect of supplementing yoghurt with mango’s pulp fibers powder on the chemical, rheological, microbiological and organoleptic properties of yoghurt, therefore 5 treatments of yoghurt were made. Control yoghurt treatment was prepared without mango’s pulp fiber powder. The other four treatments were made by adding 0.5, 1.0, 1.5, 2.0% mango’s pulp fiber powder.
All treatments were stored in the refrigerator for 12 days and were sampled at 0, 3, 6, 9 and 12 days of storage period for sensory evaluation, chemical, microbiological and rheological properties. The obtained resullts can be summarized as follllow::
1- Supplementation of yoghurt with mango’s pulp fibers powder caused a significant increase in titratable acidity of the resultant yoghurt treatments and this increase was proportional to the rate of fortification. pH values followed opposite trends to those of acidity.
2- Total solids content of yoghurt increased significantly by supplementing yoghurt with mango’s pulp fibers powder. On the other hand, total solids of all yoghurt treatments did not change significantly during storage period.
3- Fat content of yoghurt was not affected significantly by suppl- ementing yoghurt with mango’s pulp fibers powder, fat content of all yoghurt treatments did not change significantly during storage period.
4- Supplementation of yoghurt with mango’s pulp fibers powder caused a slight increase in total protein and ash content of the resultant yoghurt treatments and this increase was proportional to the rate of supplementation. Total protein and ash content of all yoghurt treatments did not change significantly during storage period.
5- Supplementation of yoghurt with mango’s pulp fibers powder caused a significant reduction of whey syneresis and this reduction was proportional to the rate of supplementing yoghurt with mango’s pulp fiber powder. Whey syneresis of all yoghurt treatments decreased up to the sixth day of storage period then increased up to the end of storage period.
6- Supplementing of yoghurt with mango’s pulp fibers powder caused a significant increase in curd tension. Curd tension of all yoghurt treatments increased during storage period.
7- Total bacterial, streptococci, lactobacilli and bifidobacterial counts followed similar trends during cold storage of yoghurt, their counts increased up to the third day, while lactobacilli increased up to the sixths day of storage, then all their counts declined as storage period proceeded up to the end of storage period.The counts of bifidobacteria increased by supplementing yoghurt with mango’s pulp fibers powder and this increase was proportional to the rate of supplementation. On the other hand, moulds and yeasts were not detected during the first 6 days of cold storage of all yoghurt treatments, and then they appeared and increased slightly up to the end of storage period.
8- Scores of organoleptic properties (flavor, body and texture, appearance, acidity) followed almost similar trends. Yoghurt treatments those made by supplementing yoghurt with 1.5% mango’s pulp fiber powder gained the highest scores.
It could be concluded that supplementing probiotic yoghurt with mango’s pulp fibers powder up to 1.5% improved the organoleptic properties, decreased the whey syneresis and improved the viability of bifidobacteria and decreased the count of total bacterial counts, therefore it could be making good quality symbiotic yoghurt by supplementing yoghurt with 1.5% mango’s pulp fibers powder. Also, it could be possible to make a good quality chocolate ice milk by supplementing ice milk with 1.5% mango’s peel fibers powder.