الفهرس 
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Abstract
The obtained results coluld be summarized as follow.
Physio-chemical characteristics of fresh acerola juice and its freeze-dried powder: The moisture content and total soluble solids (T.S.S) of fresh acerola juice were 90.24 and 9.24%,respectively. The reducing sugars, non –reducing sugars and the total sugars content were increase by freeze-drying process. They were recorded 2.69 for reducing sugars in fresh juice,1.6 for non-reducing sugars in fresh juice 4.29% for total sugars in fresh juice, 50.94% for reducing sugars in freeze-dried powder and 19.86 for non – reducing sugars in freeze-dried powder. Acerola juice showed a good content of vitamin C,1545.2 mg/100g. Fresh acerola juice had 417.70 mg/100g of anthocyanins, but the freeze-dried powder for the same fruirt had 382.02mg/100g. The color index was measured at 420nm,it was recorded 0.16 for the fresh juice and 0.90 for the freeze-dried powder and the rehydration ratio was 1.64:1.
• Indentification of organic acids in fresh acerola juice and its freeze-dried powder by HPLC
The organic acids from fresh acerola juice and its freeze-dried powder showed different profiles indicated the presence of oxalic (14.71 mg/100g), citric (35.6 mg/100g), succinic (31.9mg/100g), lactic (52.5 mg/100g), formic (3.53 mg/100g) mallic (58.5 mg/100g) and propionic (6.03 mg/100g) in fresh acerola juice, while the freeze-dried powder of acerola was identified of oxalic (27.12 mg/100g), mallic (20.26 mg /100g), lactic (12.89 mg/100g), and propionic (4.45 mg/100g). Also, there are some organic acids disappeared from the freeze-dried powder such as: citric, succinic and formic although they were in the fresh juice.
• Identification of phenolic compounds in fresh acerola juice and its freeze-dried powder by using HPLC
The juice from fresh acerola fruit contained gallic (5.83mg/100g), syringic (2.89mg/100g), 3-Hydroxy-Tyrosol,(17.92mg/100g), pyrogalol (23.39 mg/100g), 4-aminobenzoic (0.32mg/100g), protocatechoic (1.22 mg/100g), catechin (6.3mg/100g), chatechol (25.96mg/100g), chlorogenic (10.6mg/100g), caffeic (56.79) vanillic (237mg/100g), caffeine (0.92mg/100g) ferulic (4.15mg/100g), Benzoic (11.85), salicylic (20.82 mg/100g) coumarin (1.82mg/100g) and cinnamic (0.79 mg/100gm). As seen from the above resuls ,caffeic, catechol and pyrogallol were the major phenolic compounds in the fresh acerola gallic (5.83 mg/100g), syringic (2.89mg/100g), 3-Hydroxy-Tyrosol,(17.92 mg/100g), pyrogalol (23.39mg/100g), 4-aminobenzoic (0.32 mg/100g), protocatechoic (1.22mg/100g), catechin (6.3mg/100g), chatechol (25.96 mg/100g), chlorogenic (10.6mg/100g), caffeic (56.79) vanillic (237 mg/100g), caffeine(0.92mg/100g) ferulic (4.15mg/100g), Benzoic (11.85),salicylic (20.82mg/100g) coumarin (1.82mg/100g) and cinnamic (0.79mg/100gm). As seen from the above resuls ,caffeic, catechol and pyrogallol were the major phenolic compounds in the fresh acerola juice
• Identification of flavonoid compounds for acerola juice and its freeze-dried powder
The content of major flavonoid detected in Hespirdin ranged from highest concentration 84.50 mg/100g for juice while in freeze dried powder, the results showed that the major compound detected in Narenginin ranged from highest concentration 12.58mg/100g to the lowest concentration of Narenginin 5.07 mg/100g,while the lowest in freeze dried powder was rosmarinic reached 0.12mg/100g.
• Effect of the freeze-drying process on the color attributes of the fresh acerola juice
The fresh acerola juice had the lowest ”b” value 0.09, while it was increased in the freeze-dried powder 15.71. It this clear that, freeze-drying process was effected on L” and ”a” values by decreasing. The chroma value (C*)of the freeze-dried powder recorded the highest score 17.81.Also, hue angle (h°)was increased by freeze-drying process. It was recorded 39 in fresh juice and 61.93 in freeze-dried powder
• Some physio-chemical characteristics of annona extract and it is freeze-dried powder
Moisture content was decreased from 78.63 in the fresh juice to 9.58 in freeze-dried powder.Titrable acidity was expressed as citric acid equivalents and has a value of 0.26%for the fresh juice and 0.35% for the freeze dried powder.The ascorbic acid content in fresh annona juice and its freeze- dried powder, which were measured by using HPLC, were recorded 6.93 and 27.85 mg/100g ,respectively. Color index measured at 420 nm recorded 0.29 and 0.52 for fresh juice and its freeze-dried powder, respectively. The rehydration ratio for freeze-dried annona powder recorded a high score, 1.99:1.
• Identification of organic acids content of fresh annona extract and its freeze-dried powder by HPLC
The organic acids from fresh annona extract and its freeze-dried powder showed, the fresh annona extract comtained 7 peaks by identification as oxalic oxalic (1.46 mg/100g), citric (19.82mg/100g), lactic (10.94/100g), formic (0.576mg/100g), fumaric (12.37mg/100g), propionic (6.22 mg/100g) and acetic (6.50mg/100g). As seen, citric, lactic and formic acids recorded the highest concentrations. In freeze-dried powder, two organic acids were disappeared from HPLC chromatograms.
• Identification of phenolic compounds for annona juice and its freeze dried powder A total of twenty one phenolic compounds were detected in annona extract and only eight compounds in its freeze-dried powder . The major phenolic compounds in annona extract were chatchien (29.56mg/100g) and oleuropein (8.29mg/100gm).
Identification of flavonoid compounds in fresh annona extract and its freeze-dried powder
A total of six flavonoids were detected in annona juice. These flavonoid compounds, rosmarinic (11.35mg/100g),quercetrin (0.13mg/100g), narenginin (0.19 mg/100g), luteoin (3.39mg/100g) and Apignin (0.30 mg/100g). In freeze-dried powder, there are three flavonoid compounds were disappeared such as rosmarinic, narenginin and apignin.
• Effect of freeze-drying process on the color attributes of the fresh annona juice:
The fresh annona juice had the lowest ”b” value 0.09, while it was increased in the freeze-dried powder 15.71. It is clear that, freeze-drying process was effected on L” and ”a” values by decreasing.The chroma 17.81 and hue angle (h°) were increased by freeze-drying process. It was recorded 39 in fresh juice and 61.93 in freeze-dried powder
• Some physico-chemical characteristics of red and yellow cactus juices and their freeze-dried powders
The physico- chemical quality parameters of Opuntia ficus indica juices and their freeze-dried powders. juices of both, red and yellow cactus were low acidity 0.06 and 0.046 for respectively as indicated by comparatively high pH-values (5.29and 5.33 for red and yellow cactus ,respectively. The moisture content for both cactus juice were 87.66 and 87.73% for red and yellow cactus juice, respectively. Both cactus juices had a high content of ascorbic acid 11.69 and 9.99 mg/100g for red and yellow cactus juice, respectively. For freeze-dried powders it recorded 8.69 and 7.84 mg/100g for red and yellow cactus, respectively . The content of phenolic compounds as gallic acid in cactus juices are 21.43 and 11.43 mg GA/100g for red and yellow cactus, respectively, while, in the freeze-dried powders were 5.36 and 2.26 mgGA/100g for the same samples, respectively. As seen, the red cactus juice and freeze dried powder) contains a higher content of phenolic compounds compared with that of yellow cactus (juice and freeze-dried powder). The red cactus juice had a higher content of antioxidant activity 92%) compared with that of yellow cactus juice (87.938%).
• Identification of organic acids content of fresh red and yellow cactus juices and their freeze-dried powders by HPLC
Red and yellow cactus juices were contained the same organic acids by different concentrations, except mallic acid it was presented in yellow cactus juice only by high concentrate of 18.18mg/100g .
• Identification of phenolic compounds for red and yellow cactus fruits as juices and their freeze-dried powders by using HPLC.
the major phenolic compound at the red cactus juice were ellagic (9.64mg/100g), oleuropein (3.36 mg/100g), benzoic (2.98mg/100g) and vanillic (2.81mg/100g). While, the major compounds at yellow cactus juice were oleuropien (3.30mg/100) and cinnamic (0.85 mg/100g).
• Identification of flavonoid compounds in red and yellow cactus juices and their freeze-dried powders by HPLC .
Cactus juices (red and yellow fruits) contained nine flavonoid compounds. hespirdin was absent from yellow cactus juice and appeared in red cactus juice by high amounts (17.20mg/100g). On the other side, rosmarinic was absent from red cactus juice and appeared in yellow cactus juice (0.89 mg/100g). Hespirdin recorded the highest amount (17.20 mg/100g) for red juice, luteoin recorded the highest amount (1.86mg/100g) for yellow juice. On the other hand luteoin recorded the highest amount (2.37mg/100g) for red freeze-dried juice, luteoin recorded the highest amount (1.92mg/100g) for yellow freeze-dried juice cactus .
• Effect of the freeze-drying process on the color attributes of the fresh red and yellow cactus juices:
Red cactus juice showed lower value of L (28.84) than the yellow cactus juice (30.53), while the freeze-dried powder for red cactus was recorded a high level of L (65.97) than the same in freeze-dried powder for yellow cactus (39.24).
• Thermal and flow properties selected tropical fruits
The rheogrames of the tested juices, which were homogenized before being subjected to rheological test. The relationship between the applied shear rates and the corresponding shear stress responses were not linear indicating the non-Newtonian behavior of the juices obtained from acerola, annona, and cactus fruits. The magnitude of the obtained shear stress values varied according to the type of fruit and its composition Maximum shear stress response (at shear rate of 145.8s-1) were 81 s-1 and 59.87 Dynes/cm2for juices obtained from acerola and annona respectively. On other side, the juices of yellow and red cactus fruit recorded lower shear stress values at the same shear rate145. 8s-1, being 27. 68 and 68 Dynes/cm2, respectively.
• Flow parameters of juices obtained from acerola, annona and cactus fruits and reconstituted powder
According to power law equation, the n-value ( flow behavior index) of tested juices was in the range of 0.222 to 0.5203 indicating the pseudoplastic behavior of the tested fruit juices. The highest values of consistency coefficient (K-value) was recorded for acerola juice (14.70 Dynes.sn /cm2), while the lowest values was recorded for the enzyme treatment of red cactus juice (4.766 Dynes.sn /cm2). The highest values of R2 were recorded for enzyme treated yellow cactus juice (0.998), while the lowest values were recorded for annona juice (0.868).The rheological parameters of the reconstituted freeze dried juices showed that the n-values were in the range of 0.562 to 0.695, being higher than their corresponding n-values of the fresh juices. The lowest values were recorded for red cactus reconstituted juice.
Sorption characteristics of juice powders obtained from acerola annona and cactus fruits
Smith equation was the most suitable model to represent the sorption isotherm curves of acerola and annona juice powders, since the MSE values were the lowest (0.00012 to 0.00558)high R2-values (0.857 to 0.9923). Smith model was not suitable for the sorption data of cactus juice powders due to the high percentage of deviation modules E% (12.29 and 74.84). Henderson and BET models showed higher values of MSE (0.0268 to 6.777) and low R2 values (except for Acerola and Annona juice powders).
• Antioxidant status of strawberry jam fortified with freeze dried tropical fruits powder.
the results showed that supplementation of strawberry jams with freeze dried tropical fruits powder during processing, enriched these products in bioactive compounds.