الفهرس 
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Abstract
Minimally processed fruits are fresh like state with high moisture content. Slightly treated fruits are much perishable than the intact fruits. The reasons include the post-harvest damage during processing and handling, high moisture and nutrient content, absence of heat or other treatments to eliminate pathogenic and spoilage microbes and the possible temperature abuse during processing, storage and marketing of these products.
The importance of considering of combing action of preservation parameters (hurdles) as a way to develop new important and shelf-stable fruit product has been undertaken in the present investigation. Two different approaches (strategies) were explored:-
The first way was an attempt to produce fruit compotes (fruit slices packed in glass jars with enough syrup to cover them) with non-thermal sterilization (NTS). The progressing and application of cheap preservation methods to produce good quality and accepted products of these fruit compotes could be useful, enabling better usage of the fruit. Therefore, the classical method of hurdle technology was applied. These made of blanching followed by an activity water depression step, which contains sucrose syrup contained , citric acid (pH 3.0 - 4.1), potassium sorbate or sodium benzoate, and sodium bisulphite. These minimal processes have proved to be energetically efficient and very simple to carry out, resulting fresh-like products of long shelf-life and high sensory quality, especially for texture which is often problematic for canned fruit. The syrups were prepared by dissolve appropriate amounts of sucrose, sodium benzoate, potassium sorbate, ascorbic acid, and sodium bisulphite in hot water (80 ºC), the pH was measured and adjusted with citric acid to the corresponding level. The syrup heated to 90ºC and used as covering liquid for the fruit compotes slices in glass jars.
Four hurdle designs were applied using in different treatments: T1 was applied for mango slices. The hurdle concept was (steam blanching + 25oBrix + pH 3.60 + 0.75% potassium sorbate + 0.50% ascorbic acid + 0.45% sodium bisulphite). T2 was used for pineapple slices (osmodehydrated pineapple +steam blanching + 20 oBrix+ pH 3.40 + 0.50% sodium benzoate +0.50% ascorbic acid + 0.34 % sodium bisulphite). T3 was conducted for papaya slices (steam blanching + 20oBrix + pH 3.60 + 0.75% Potassium sorbate + 0.50% ascorbic acid + 0.45% sodium bisulphite). On the other hand, mixed fruit salad composed of slices of mango and kiwi and cubes of apple and cantaloupe in the ratio of 1:1:1:1 was used for T4. The hurdles were (steam blanching + 25o Brix+ pH 3.60+ 0.50 % ascorbic acid + 0.45 % sodium bisulphite + cinnamon extract (1%). In all treatments refrigeration is the largest hurdle for producing shelf stable fruit compotes.
In the second part in this research, ready to eat MPR product (intermediate moisture) was prepared. Peach fruits were cut into halves steam blanched and subjected to osmotic dehydration using sucrose solution (40%) at ambient temperature (25-30oC) for 4 hours. The pH of the syrup was adjusted with citric acid to 3.60. Potassium sorbate (0.75%), sodium bisulphite (0.45%) and ascorbic acid (0.50%) were then added to the syrup. Afterward, peaches were drained, packed under vacuum in laminated polyester nylon and stored at 4±1oC.
Physicochemical analysis (total soluble solids, pH, total acidity, color parameters, total phenols, total sugars, and ascorbic acid) and microbial count along with sensory evaluation were measured at storage period intervals.
The results obtained could be summarized in the following points:
• With regard to the processed NTS compotes, the results showed that the drained weight % was in the range of 59.70% to 63.77%. TSS % varied between 20 to 22 o Brix. The pH values ranged between 4.12 to 4.88. While TA was in the range of 0.14% to 0.16 % as citric acid.
• In addition ascorbic acid varied between 33.35 mg/100g for T3 and 71.59 mg/100g for T1, whereas phenolic compound ranged between 21.97mg/100g for T2 to 42.85 mg/100g for T4. The overall acceptability mean score of judges for NTS compotes (T1 - T4) was 9.02, 8.93, 8. 56, 8.75 respectively.
• The results showed increase in acidity and decrease in pH with progressing the storage time at 4 o C. Ascorbic acid gradually declined during storage the highest loss was found in T3 compote 60.72% while the lost was 29.57% for T1 compote. While T2 and T4 lost 56.55% and 48.02% respectively at the end of the storage period. On the other hand, total phenolic compounds (TP) successively increased during cold storage of all types of NTS compotes. Moreover, total sugars increased with increasing the storage period irrespective of treatments.
• It was interesting to note that the rate of bacterial growth varied with different hurdle treatments, the high inhibitory effect on bacterial growth was found in T1 and T2 compotes until 10 month (the termination of storage period) depends on concentration level and hurdle chemical additives. The preservation had been seriously active to stop the microbial growth. In the case of T3 compote the bacterial count reach 5.52 after 10 month of cold storage but still less than the limit count of spoilage. Similar trend of results was obtained for Y&M counts.
• Small changes were observed in the color parameters in T1 mango compote and T2 pineapple compote and T3 papaya compote due to self-stabilization by the combined effect of hurdle technology up to 10 months of storage. Whereas the reduction in L* value and the increment in a* value are indication for browning of apple cubes in fruit salad compotes.
• The maximum scores for overall acceptability were 8.30 and 8.08 recorded for T1 and T2 revealing prolonged keeping quality upto 10 months of storage. However, there was a reduction in overall acceptability scores of T3 compote but still in moderate acceptability (6.61) during 10 month of storage. However, the fruit salad compote (T4) preserved by the natural antimicrobial cinnamon extract (1%) was not acceptable at 6 months of storage period (4.58).
• Concerning the ready to eat peach-halves, the result revealed that the shelf-life of MP peach-halves stored at ambient temperature was limited to 2-3 days maximum.
• During 60 days of peach-halves storage at 4 o C a decrease in pH, ascorbic acid (mg/100g), color (L* value) and sensory characteristics were observed.
• The MPR peach-halves showed good general acceptance up to 30 days of storage (4±1oC). Regardless of microbiological safety during the 60 days of cold storage, the color was considered to be the quality boundry factor of MPR peach-halves. The treatment was efficient to maintain quality with shelf-life of about 35 days, afterwards the color become strong enough to affect the appearance.
• The results of the present investigation can consider useful to the fast food industry and other ready-to-eat products, attending the requirement for healthy and convenient food stuffs.