الفهرس 
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Abstract
Fruit and vegetables juices (turbid or clarified) as natural juices and the products manufactured from them, such as, concentrates, concentrated syrup, nectar and various drinks are considered the main branches of food industries. Juices and their derivatives are characterized by having nutritional and therapeutically components; moreover it’s highly economic value. Prickly pear is considered one of the promising fruits in Egypt, whereas its cultivation spread widely as it survives the gruel weather and it grows well in desert. Rather than the nutritive value and healthy benefits, it’s widely handled now and several researches were conducted about the benefits of the various cultivars of prickly pear fruits as well as the various products produced from them. Based on the whole data obtained and discussed of this work, it could be summarized that as follow: 1- Physico-chemical properties of fresh prickly pear juice: *The pulp of yellow and red fresh prickly pear juice were (55.1% and 54.8%), moisture content was 84.62% and 84.10%, total soluble solids (T.S.S.%) 13.25% and 12.08 %, pH value 5.72 and 6.12, color index at (420nm) 0.785 and 0.890, viscosity content were 60cp and 55 cp, clarity of tow fresh juices (yellow and red) measured at (660nm) ,the percent of light transmission were 24.8% and 24.1%. *Total sugars of fresh yellow prickly pear juice was 11.20% and in the red juice was 10.78 %. While the reducing sugars content in fresh yellow prickly pear juice, were 10.68% and 9.20 %, in the fresh red the fresh black mulberry juice contained about 28.22 mg/100g from Lascorbic acid. *The total antioxidant capacity (%), total flavonoids, total anthocyanin (mg/100g) and total phenols, among the phytochemical compounds of fresh black mulberry juice were 53.72 %, 52.32 (mg/100g), 212.77 (mg/100g) and 434.61 (mg GAE /100g) respectively. 3- Identification of phenolic compounds detected in the fresh yellow and red prickly pear juice as well as mulberry juice using High Performance Liquid chromatography (HPLC): *Seventeen phenolic compounds (phenolic acids and various derivatives) of analytical standard were used as available authentic samples found in FTRI lab. *Based on the quantity detected in yellow prickly pear juice , high ratios of benzoic acid (19.51 mg/100g), followed by olewoprein (9.99 mg/100g),catchin (6.98 mg/100g ), 3- hydroxyl-terosol (3.26 mg/100g) were detected. After that ,quercetin , chlorogenic acid, catechol, gallic acid ,protpcatchioc and caffien were found at the ratios of (1.830,1.67, ,1.61,1.58,1.25 and 0.95 mg/100g) respectively. Salcylic acid, ellagic, ,cumarin,caffiec,cinamic acid, ferulic acid and vanillic acid were presented of yellow juice as small quantity, which were (0.66 0.65, 0.60, 0.23, 0.0.17, 0.15 and ,0.11 mg/100g ) respectively. *Concerning the red prickly pear juice, also seventeen compounds of phenolics. But , higher concentrations and minor variation in the type of phenolics than that found in the yellow juice. For example: Chlorogenic acid was found to be 17.65 mg/100g , salicylic acid was 15.249 mg/100g, catchin was 13.932 mg/100g , 3- hydroxyl-terosol was 9.721 mg/100g, 137 gallic acid was7.832 mg/100g ,ferulic acid was 4.99 mg/100g and ellagic acid which was 2.39 mg/100g respectively. *Mulberry juice have fourteen phenolic compounds among the authentic samples of standard, whereas it contains high concentrations from most of them. 3- hydroxyl-terosol, oleuropein, catechol, benzoic, chlorogenic acid, salicylic acid, catchin, ellagic, caffeine, ferulic, caffic, gallic, vanilic and cenamic acid were detected at the concentration of ( 9.414, 3.513, 2.878, 2.789, 23.75, 1.729, 18.20 , 16.05 , 4.41 , 4.30 , 4.14 , 2.68 , 2.37 and 1.49 mg/100g respectively. 4. Clarification processes: *Clarification process is very important technology for several fruit juices, to improve their qualities such as overall acceptability for the consumers and overcome the disadvantage of hazing phenomena of some fruit juices. So , three technical procedures of clarification processes such as conventional method( gelatin agent), enzymatic clarification as well as Ultrafiltration processes were used in this work. a.Effect of gelatin agent on some parameters of clarified mulberry juice: *As conventional method, gelatin agent was used in this study to clarify the mulberry juice. For that reason, gelatin is a frequently used clarifying agent by fruit processing industries at the present. *The pH value was somewhat constant in treated black mulberry juice, which was 5.45 and 5.49 in untreated mulberry juice. Clarity and viscosity are the two impressive parameters as physical properties of treated juice with gelatin agent. *The clarity increased from 35.9% of single strength fresh juice or turbid juice to 75.5% in the case of clarified juice, by adding gelatin agent, 138 the viscosity was decreased from 70 cp in turbid juice to 55 cp in clarified black mulberry juice. b. Optimization of pectolytic enzyme concentration and its effect on some parameters of clarified yellow and red Prickly pear juices: *To explore the influence of Ultra SPL enzyme on some parameters of single strength yellow and red prickly pear juice, total soluble solids (TSS %), pH value, clarity at (T660 nm) and viscosity were evaluated. Varying concentrations (100, 200, 500, 600 and 700 ppm) from pectinex enzyme were conducted, with constant conditions (temperature and time) to choose the appropriate enzyme concentration. *The proper concentration of added pectic enzyme under specific conditions, in both yellow and red prickly pear juices was 500 ppm, based on the increasing of total soluble solids (TSS%) and the clarity (%), as well as the higher reduction ratio of measured viscosity. *The concentration of 500 ppm from pectinex, total soluble solids (TSS%) increased from 13.25% of fresh yellow juice and 12.8% of red juice to 13.8% of treated (clarified) in yellow juice and 13.5% in the clarified red prickly pear juice. *The transmission of clarity (%) in yellow juice reached 24.8%, when adding 100 ppm of enzyme whereas it reached 89.5, 89.6 and 89.7 % at the concentration of 500, 600 and 700 ppm respectively. In the case of red prickly pear juice, the clarity (%) reached (33.8%), when adding 100 ppm of enzyme, whereas it reached (89.4, 89.4 and 89.3%) at the concentration of 500, 600 and 700 ppm respectively. c. Effect of Ultrafiltration process (UF) on some properties of resultant prickly pear juices. *Some of estimated evaluations in tow cultivars of fresh prickly pear juice (yellow and red), were determined, such as total soluble solids (TSS %), pH value, clarity (T660 nm) and viscosity to judge the efficiency of the clarification possessing using UF process. *Total soluble solids (TSS%) and pH value of UF clarified juices are somewhat constant in both yellow and red prickly pear juice. The effect of UF in total soluble solids (TSS %) and other physical properties are rely on the nature of UF membrane, which applied in the this study. Slightly changes se in pH value during the enzymatic reaction in both clarified juices. Clarified yellow and red prickly pear juice coming from Ultrafiltration process, has a high reduction percent of viscosity, It reduced from (60 and 55 cp) in the case of fresh single strength tow juices to (12 and 11 cp) in UF clarified yellow and red prickly pear juice respectively. d. Ultrafiltration process of mulberry juice. *Mulberry juice coming from Ultrafiltration process is characterized with having a good physical properties, such as high transmittance of clarity and noticed reduction in viscosity, The fresh mulberry juice has 35.9% of light transmission as clarity indication, while it was 95.5% in the UF clarified juice. Also, viscosity is considered one of the most properties, which declare that the importance of clarification process. It was (10 cp) in UF implemented juice, compared with 70 cp in single strength fresh mulberry juice. pH value remain unchanged in UF clarified mulberry juice. 140 5. Some phsico-chemical properties of reconstituted clarified prickly pear juices and mulberry juice as affected by concentration process: Concentration process one of the most important methods for preservation of fruit juices or pulp, where it facilitate transportation , storage and processing into various products. It is considered an intermediate stage for another industries ,and can be added to another products such as some of dairy products ,soft drinks carbonated drinks. *The physical and chemical analysis, microbiological and sensorial evaluations were conducted to declare and choose the optimal technological processes in this work. Concentration process of juices were implemented using three different methods ( Under vacuum, serum pulp and freezing concentration. *To analyze and evaluate the physico-chemical constituents as well as the sensory properties of the concentrates , it is a must to reconstitute the concentrates into the initial total soluble solids as found in the fresh juice. *Results indicate that the freezing concentration , led to produce the reconstituted juice having high quality properties than others. *The results showed that , the juice coming from UF processing was somewhat surpassed the tow others. Whereas the juice coming from enzymatic reaction was also characterized of other properties , such as sensory properties. The clear mulberry juice coming from the clarification by gelatin agent having a lower stability than UF implemented juice in their quality attributes. 6. Sensory properties of concentrated juices at zero time after processing directly: *After clarification and also concentration processes directly, sensory properties of all samples used were conducted and the resultant data was analyzed statistically to show the significancy between the treatments. *Each of clarification process method and also concentration process method had accepted color, taste, aroma and overall acceptability. Remarkable that, there were significant differences between various processing within sensory properties. This confirm that the physical properties of clarification processes cope with the sensory properties of processed juices. 7. Phsico-chemical properties of reconstituted clarified prickly pear juices and mulberry juice as affected by storage conditions: *The study was conducted to show the effect of storage on physiochemical properties and consumers acceptability of the reconstituted yellow prickly pear juice coming from freeze concentration during a storage period for four months when, kept at room temperature. *Concentrated juices were stored at room temperature 25C º ± 5C º for a period of four months. Reconstituted juices were analyzed physically , chemically and microbiologically to study the quality properties of reconstituted juices during storage period , and the results were summarized as follow. *The initial pH value was 4.85 at zero time of yellow and 5.98 for red juice, while at the end of the four months storage period were 4.74 and 5.65 respectively .