الفهرس 
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Abstract
Objectives:
This work was conducted at Dairy science Dept., Fac. Agric., Damietta University. The objective of this study is to:
The aim of this study was to blend different high nutritional value ingredients with goat’s milk and using probiotic culture (ABT-5) in production of Bio-rayeb milk.
Results:
- Chemical analysis:
Fortification of Rayeb milk with Tamr extract increased the total solids, dietary fiber and carbohydrate contents which increased its nutritional value. Also. Blending of guava pulp and sugar with goat’s milk increased TA, Eh and Carbohydrate, while decreased pH values. Fortification of goat’s milk with guava pulp and sugar increased starter activity. Mixing Talbina and honey with goat’s milk increased TA, Eh and carbohydrate while decreased pH values. Adding vanilla had no clear effect on acidity, pH and Eh values of goat’s milk mixed with Talbina and honey whereas incorporation cocoa powder markedly increased acidity and Eh and lowered pH values. The levels ofomega-6, omega-3 and omega-9 were higher in Tamr extract rayeb milk than those determined in control.
Rheological analysis:
Curd tension and water holding capacity values increased in Tamr extract rayeb milk treatments comparing with control. On contrary, values of susceptibility to syneresis (STS) were markedly low in fermented goat’s milk samples contained Tamr extract.
Curd tension and water holding capacity values increased but STS levels lowered in goat’s milk supplemented with Tamr extract and honey. Curd tension and water holding capacity values of goat’s milk and guava pulp and sugar mixtures were higher as compared with control. STS levels were lower in the former than the latter. Addition Talbina and honey to goat’s milk increased the curd tension and water holding capacity values and decreased STS results.
- Microbiological analysis:
Analysis included bacterial count, Lactobacilli acidophilus, Streptococcs count, Bifidobacteria count on MRS agar and M17 agar. Results showed the following:
- Fortification of goat’s milk with Tamr extract increased Str. thermophillus, L. acidophilus and Bifidobacterium bifidium counts in rayeb milk. Bifidobacteria counts remained above 106 cfu.g-1 in all rayeb milk treatments during storage period.
Incorporation of Tamr extract and honey with goat’s milk increased Str. thermophillus, L. acidophilus and Bifidobacterium bifidium counts in rayeb milk. The recommended level of 107 cfu.g-1 of bifidobacteria as a probiotic was exceeded for these treatments. The population of Str. thermophillus, L. acidophilus and Bifidobacterium bifidium increased in rayeb milk samples fortified with guava pulp and sugar as compared with control. The viability of bifidobacteria in guava rayeb milk was always above the minimum recommended level of 107cfu.g-1, suggested for beneficial health effects in the gut. The populations of S. thermophillus, L. acidophilus and Bifidobacterium bifidium were higher in the presence of Talbina, honey, vanilla or cocoa powder in rayeb milk. Bifidobacteria in fortified and flavoured rayeb milk remained above the 106 cfu/g recommended dose for consumption to receive health benefits of these organisms.
- Organoleptic evaluation:
The final products of all treatments were controlled by a group of faculty members from the Dairy Department, Faculty of Agriculture, Damietta University. As the storage period advanced the total scoring points increased for all treatments.
, mixing (5, 10 or 15%) Tamr extract with goat’s milk highly improved the sensory evaluation scores of Bio-rayeb
Adding 10% Tamr extract with 3% honey or 15% Tamr extract with 1 or 2% honey to goat’s milk highly improved the sensory attributes of Bio-rayeb milk
mixing guava pulp with rayeb milk which main that guava pulp could be utilized as sweeter and prebiotic in Bio-rayeb milk production
The results of this study has cleared that fortification rayeb milk with 15% Talbina and 4% honey and addition 0.1% vanilla or 0.5% cocoa powder as flavourings produced an acceptable functional fermented dairy product with potential beneficial health aspects.