This study was carried out to estimate the effect of adding pomegranate (Punica granatum L) and cactus pear (Opuntia ficus indica) juices as natural ingredients on physico-chemical characteristics, antioxidant activity, microbiological examination and sensory evaluation of stirred yoghurt. Stirred yoghurt was prepared by using cow , s milk 3% fat, and pomegranate and cactus pear juices were added at the rate of 5%, 10% and 15% W/W. All treatments were inoculated with 2% of yoghurt starter and stored at 5°C up to the end of storage period (15 days) after complete a sulation. Physico-chemical properties of yoghurt samples such as total solids, protein, fat, pH, syneresis, viscosity was carried out .Also, microbiological examination and sensory evaluation were determined of all the treatments when fresh ,and then after 5, 10 and 15 days of cold storage at 5°C. The results showed that significant differences were found between the control and stirred yoghurt fortified with juices in the total solids, protein content, pH and titratable acidity up to the end of storage period(15 days). Addition of pomegranate and cactus pear juices led to significant increase in phenolic compounds and antioxidant activity of yoghurt treatments compared with the control sample. In all samples, it was observed that the titratable acidity increased over the storage period. Low values for viscosity and high values for syneresis were belonged to yoghurt containing 15% pomegranate and cactus pear juices. Sensory evaluation results showed that there were significant differences among the yoghurt samples. Stirred yoghurt (control) and stirred yoghurt containing 5% cactus pear or pomegranate juices gained significantly highest flavour and texture scores compared to stirred yoghurt treated with 10% or 15% juices. The results of current study demonstrated that the addition of juices from pomegranate and cactus pear to stirred yoghurt milk, significantly improved the quality of yoghurt and will increase its healthy benefits.

Cephalotyre (Ras) cheese slurries developed within 7 d of storage at 30 °C a flavour similar to that of conventional Ras cheese ripened for 2 months. Addition of a proteinase/lipase mixture, trace elements or Na citrate to fresh cheese slurries before storage at 30 °C enhanced flavour development. Additive-treated slurries showed after storage for 5 d at 30 °C a strong flavour similar to that of 3-4 months Ras cheese with increased protein degradation, acidity development, volatile fatty acid formation and higher bacterial counts. The effectiveness of the additives in enhancing flavour development and related chemical changes was in the order: proteinase/lipase mixture > trace elements > Na citrate.The conventional long-time curing process for ripening of cheese is still the prevailing custom. Cephalotyre ' Ras', known as Ras cheese, is the national hard type in Egypt. This cheese is normally marketed after a ripening period of 4 months. This period gives a fully ripened product with a pungent flavour, close to that of Kachkaval cheese.An urgent need exists for manufacturing and curing techniques which will both accelerate and provide control over the development of full flavour in the cheese. Kristoffersen et al. (1967) developed a process of accelerating flavour development in Cheddar cheese curd in which 24-h-old salted unpressed Cheddar curd was blended with 5-2% NaCl solution and the homogeneous slurry stored at 30 °C. The slurries containing about 40 % total solids developed a strong flavour in days rather than in months. The same authors reported that the liquid cheese product would appear to be ideally suited for making spray-dried cheese powder, heat and cold processed cheese, and cheese-containing bakery goods.Rapidly ripened cheese slurries have been used by some investigators in the processing of dairy products. Sutherland (1975) showed that it was possible to replace the matured cheese components in processed cheese with ripened cheese slurries, and Dulley (1976) recommended the use of ripened cheese slurries to accelerate the ripening of Cheddar cheese.The present work was carried out to provide information on the properties of slurried Ras cheese curd as affected by its incubation at 30 °C for several days. The effect of incorporating into the fresh slurries proteinase/lipase, trace elements or Na citrate prior to incubation at 30 °C was also investigated.