الفهرس 
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Abstract
Preserving the fruit pulp is an alternative source to recycle the surplus for use in the off-season and to manufacture various products such as jam, nectar and various drinks. The use of some chemical preservatives in fruit pulp and juices is effectively to extend the shelf life and to significantly improve the organoleptic quality of the food. It is the main objective of this study to preserve the pulp of mango, guava, apricot and orange juice and to evaluate the quality and storability of these products.
The results of the study that was conducted are summarized below:
Physical and chemical characters of fruits:
The results showed that mango fruit recorded the highest average values for the content of pH (4.71), TSS (14%), total sugars (10.32%), non-reducing sugars (5.72%), flavonoids (6.32%) and β-carotene (681.67µg /100g) compared with other varieties, in addition to that guava fruit recorded the highest average value in the content ascorbic acid (277.20 mg /100g), antioxidant activity (79.71%) and phenols (290.45 mg /100g), while apricot fruit recorded the highest value in the percentage of acidity (1.79%) and ash content (0.97%) also orange fruit recorded the highest value in moisture content (83.93%) and reducing sugars (3.97%) compared with other varieties.
Effect of additives on Physico-chemical characters of mango, guava, apricot pulp and orange juice during storage:
• pH showed a decreasing trend during the storage. The mango pulp recorded the highest value of pH (3.82) at (p< 0.05) compared to all cultivars. T1 recorded the highest pH value, followed by T5 (3.19 and 3.17, respectively) compared to all other treatments. T2 recorded the lowest pH value (3.11) compared with T1 and other treatments.
• The acidity (%) of stored pulp increased with the advancement of storage duration. Found that the highest acidity percent was in apricot pulp (1.65%) at (p< 0.05) compared to all varieties. T2 recorded the highest mean value of total acidity, followed by T4 (1.00 % and 0.98 %, respectively) compared to the other different treatments. While, T1 (Control positive) recorded the lowest mean value (0.91%) of total acidity content.
• There was an increase in the total soluble solids (TSS) of pulp continuously until the end of storage duration in all the treatments. Mango pulp recorded the highest value of TSS (14.67 %) at (p< 0.05) compared with all varieties. T2 (3g citric acid + 2g potassium sorbate) gave the highest value of TSS, followed by T4 (11.06 % and 10.91 %, respectively) compared to all other treatments. While, T1 (control positive) recorded the lowest value (10.25 %) of total soluble solids content.
• Moisture content showed a decreasing trend during the storage. The mango pulp recorded the highest moisture content (71.63%) at (p< 0.05) compared to all studied varieties. Moreover, T1 (Control positive) had the highest value, followed by T5 (70.03 % and 69.55 %, respectively) compared to all other. While, T2 had the lowest value (68.48%) of moisture content.
• Ash content acidity of stored pulp and juice increased with the advancement of storage duration. Apricot pulp showed the highest value of ash content (0.966%) compared to all cultivars. On the other hand, it was found that T2 had the highest value, followed by T4 (0.680 % and 0.587%, respectively) compared to all other treatments. While, T1 (Control positive) had the lowest value (0.539%) of ash content.
• There was an increase in total and reducing sugars for pulp and juice stored continuously until the end of storage duration in all the treatments.where it was found that the highest content of total sugars in mango pulp (9.30%) at (p< 0.05) compared to all varieties. Additionally, T1 (Control positive) scored the highest total sugar content, followed by T3 (6.30 % and 6.23 %, respectively) compared to all other treatments. While, T2 scored the lowest value content (6.12%) of total sugar. The mango pulp also had the highest value for the reducing sugars content (4.37%) at (p< 0.05) compared to all fruit varieties. On the other hand, T2 had the highest value of reducing sugars, followed by T4 (3.66 % and 3.61 %, respectively) compared to positive control and other treatments, while, T1 (Control positive) had the lowest value (3.51%) of reducing sugars content.
• The non-reducing sugars recorded a decreasing trend during the storage. Mango pulp registered the highest value for the content of non-reducing sugars (4.68%) compared to all other varieties. Likewise, T1 (Control positive) registered the highest value for non-reducing sugars, followed by T5 (2.64 % and 2.61 %, respectively) compared to all other treatments. While, T2 registered the lowest mean value (2.34%) of non-reducing sugars content.
• Ascorbic acid content showed a decreasing trend during the storage. Guava pulp had the highest value for vitamin C content (117.90 mg/100g) compared to all other varieties. Also, T1 (Control positive) had the highest value for vitamin C, followed by T2 (47.86 and 46.32 mg/100g, respectively) compared to all other treatments. While, T5 had the lowest mean value (43.53 mg/100g) of vitamin C content.
• Antioxidant activity showed a decreasing trend during the storage. Guava pulp had the highest antioxidant activity value (44.53%) compared to all other cultivars. In addition to that, T1 (Control positive) had the highest value of antioxidant activity, followed by T2 (24.16 and 23.90 mg/100g, respectively) compared to all other treatments. While, T5 had the lowest value (22.12%) of antioxidant activity.
• Total phenolic content showed a decreasing trend during the storage. Guava pulp had the highest mean value of total phenol content (100.53 mg/100g) compared to all other fruit cultivars. Also, T1 (Control positive) recorded the highest mean value of total phenol content, followed by T2 (65.22 and 64.70 mg/100g, respectively) compared to other treatments. While, T5 recorded the lowest mean value (58.52 mg/100g) of total phenol content.
• Total flavonoid content of stored pulp and juice decreased with the advancement of storage duration. Mango pulp had the highest mean value of flavonoid content (2.60 mg/100g) compared to all other studied varieties. T1 (Control positive) recorded the highest mean value, followed by T2 (1.77 and 1.76 mg/100g, respectively) compared to all other treatment. While, T5 the lowest mean value (1.66 mg/100g) of flavonoids content.
• β-carotene content of stored pulp and juice decreased with the advancement of storage duration. Mango pulp achieved the highest mean value for β-carotene content (194.19 μg/100g) compared to all other varieties. T2 had the highest mean value, followed by T4 (95.59 and 88.04 mg/100g, respectively) compared to all other treatment. While, T5 the lowest mean value (75.99 mg/100g) of β-carotene content.
• The non-enzymatic browning (NEB) of pulp and juice increased continuously till the end of storage duration in all the treatments. Orange juice scored the highest optical density value (0.197 OD) than the rest other varieties. Also, T1 (Control positive) recorded the highest optical density value, followed by T4 (0.179 OD and 0.160 OD, respectively) compared to all other treatments, in addition that T3 recorded the lowest value (0.133 OD) of optical density value.
Effect of additives on microbial counts of mango, guava, apricot pulps and orange juice during storage periods:
There was an increase the fungal and bacterial growth in pulp and juice preserved continuously until the end of storage duration in all the treatments. Mango pulp had the highest bacterial count (2.67 log cfu/ g), while orange juice recorded the lowest (1.55 log cfu/ g) at the end of storage duration. Moreover, T5 had the highest bacterial count (2.48 log cfu / g). While, T2 recorded the lowest (2.18 log cfu/ g) followed by T4 (2.25 log cfu/ g) at the end of storage period. The highest log cfu/ g of fungal and yeasts counts were found in mango pulp samples (2.65 log cfu/ g) followed guava pulp (2.11 log cfu/ g) and orange juice samples recorded the lowest microbial counts (1.70 log cfu/ g) at the end of storage. Furthermore, T1 had the highest fungal count (2.91log cfu/ g). While, T5 recorded the lowest (1.93 log cfu/ g) followed by T3 (2.02 log cfu/ g) at the end of storage period.
Effect of additives on sensory evaluation of mango, guava, apricot pulp and orange juice at zero time:
s ensory attributes (colour, odor, taste, Texture and overall acceptability) of the fruit samples. In general, guava pulp recorded the highest mean values (8.03, 7.95, 8.09, 7.97 and 8.07, respectively) for all sensory traits compared to all cultivars, followed mango pulp (7.71, 7.80, 8.06, 7.91 and 7.98, respectively), while treatment T3 recorded the highest mean values (9.03, 9.03, 8.63, 8.84 and 9.00, respectively) for all sensory traits compared to all treatments, followed by treatment T2 (8.23, 8.71, 8.33, 8.74 and 8.77, respectively).