﴿بسم الله الرحمن الرحيم﴾ ﴿صدق الله العظيم﴾ سورة النحل الآية 66

Curriculum Vitae Name: Ahmed Refaat Abd El-Wahab Hammam Place of Birth: Assiut, Manfalut, Bani Rafea Date of Birth: 2/9/1990 Position: Demonstrator at Dairy Science Department since 2012. (Excellent with Honor Degree) (The First in my group by average percentage 92.79%).

Ahmed Refaat Abd El-Wahab The Proposed Title Chemical and Microbiological Studies on Probiotic Ras Cheese During Ripening العنوان المقترح دراسات كيميائية وميكروبيولوجية على الجبن الراس المدعم حيويا أثناء التسوية by: Ahmed Refaat Abd El-Wahab

Under supervision of Prof. Dr. Aly Ismail Hassan Dr. Adel Ali Tammam Emirates Professor of Dairy Science Faculty of Agriculture - Assiut University (Main Supervisor) Dr. Adel Ali Tammam Associated Professor of Dairy Science Faculty of Agriculture - Assiut University. Dr. Ali Mohamed Abd El- Rahim Associated Professor of Dairy Science Faculty of Agriculture - Assiut University.

Outline INTRODUCTION AIM OF THE WORK MATERIALS & METHODS

Introduction

History of Cheese

According to Moisture Contents Cheeses are divided into 4 groups Soft cheese 50-70% Semi-hard 40-60% Hard 30-40% Extra hard less than 30%

Ras cheese is the main traditional hard cheese from the point of view concerning production and consumption in Egypt. Its manufacture in a high proportion under artisan conditions from raw cow’s or mixture of cow’s and buffalo’s milk without using starter cultures and marketed when it has a queried sharp flavour closed to kefalotyic cheese after 3 to 6 months. [Hofi et al., 1970; Scott, 1981; Phelan et al. , 1993].

Probiotic bacteria belong to the category of functional foods are described as: “Foods claimed to have a positive and good effect on human being health” [Stanton et al., 1998]. The most popular food offered system for probiotic cultures to the consumer has been freshly fermented dairy foods, such as yoghurt and fermented milks as well as unfermented milk and desserts with added cultures.

Members of the genera Bifidobacterium and Members of the genera Bifidobacterium and Lactobacillus are widely used as probiotic microorganisms in functional foods; but other nonpathogenic bacteria, including members of the genus Enterococcus and yeasts, are also used as probiotics . [Sanders & Huis in’t Veld, 1999; Corbo et al., 2001]. Recently Fathi &Dabiza [2005] reported that probiotic bacteria improved the body and texture of Ras cheese. They also reported that the final products contained viable probiotic bacteria.

The incorporation of culture with beneficial effects into a functional foods is considered successful when the added cultures maintain its viability until consumption, digestion and absorption in the intestine in the same time the added cultures don't adversely affect the composition, texture or sensory attributes of the product. Results from cheeses used as functional foods are still limited. [Corbo et al., 2001].

What are the health benefits of Probiotics?

Probiotics characteristics Human origin Acid and salt Bile Stability Clinically validated and documented health effects Probiotics characteristics Safety in food and clinical use Adherence to human intestinal cells Antagonism against pathogenic bacteria Survival in the human intestinal tract Production of antimicrobial substances

Aim of The Work

The main objective of this study Manufacture of Ras cheese with probiotic bacteria. Selection of starter culture which can improve the quality Ras cheese. To investigate the chemical and Microbiological changes of probiotic Ras cheese during ripening period.

Material & Methods

Materials Milk Starter Cultures Rennet Salts

Starter culture addition Methods Milk Heat Treatments Starter culture addition Rennet Cutting CaCl2 addition Bottoming Salting Whey drainage Scalding Ras Cheese Settlement Salting Continue Candling

The First Part (heat treatments). Temperature Time in Sec. Raw ----------------- -------------- Thermization 65 C˚ 15 Pasteurization 73 C˚

The Second Part (probiotics addition). Control T1 T2 T3 T4

Sensory Evaluation Property Points Falvour 60 Points Body & Texture Appearance 10 Points Total 100 Points

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