الفهرس 
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Abstract
This investigation was carried out during seasons 2019 and 2020 to study the effect of coating with essential oils, wrapping with waxed paper and their combination on the quality of ”Manfalouty” pomegranate fruits under different storage conditions. Pomegranate fruits used in this study were obtained from the experimental orchard of Pomology Department, Faculty of agriculture, Assiut University. Fruits were collected when they reached the appropriate stage of maturity then transported to the laboratory.
They were divided into six similar groups. Each group was exposed to one of the following treatments:
• Control (untreated fruits)
• Coating fruits with turmeric oil
• Coating fruits with ginger oil
• Wrapping fruits with waxed paper
• Coating fruits with turmeric oil + wrapping fruits with waxed paper
• Coating fruits with ginger oil + wrapping fruits with waxed paper
Half of the tested fruits were stored under room conditions and the other half was stored in a refrigerator at (5-7 °C) with R.H 85-90%. Fifteen fruits from each group under both different storage conditions were selected for weight loss percentage.
Samples stored under room conditions were used every week and the others under cold storage were used every two weeks for quality evaluation through study changes in physical and chemical characteristics under storage conditions.
5.1. Some physical and chemical properties were measured as follows
5.1.1. Physical properties
5.1.1.1. Weight loss percentage
Generally, the weight loss percentage was increased from the beginning of the storage till 8 weeks of the storage under room conditions and 20 weeks under cold storage in the two different seasons of the study. Moreover, stored fruits in refrigerator scored the best results for reducing weight loss percentage compared with stored fruits under room conditions. All treatments significantly reduced the fruit weight loss percentage compared to control, while turmeric oil or ginger oil in combination with waxed paper gave the significant lowest percentage of fruit weight loss compared to other treatments and control. Also, interaction between tested treatments and periods of storage had significant effect on decreasing fruit weight loss percentage.
5.1.1.2. Juice weight of 100 g arils
In general, by advancement the storage period, the juice weight of fruits was gradually reduced for all treatments. Moreover, in the first and second season of the study, stored fruits under cold conditions gave the best results for reducing juice weight loss compared to stored fruits under room conditions. Using essential oils, waxed paper alone or their combination significantly preserved juice weight compared to control and other treatments. However, there were no significant difference between ginger oil treatment and control under room conditions in 2020 season. The maximum values of juice weight were obtained by essential oils (turmeric oil and ginger oil) in combination with waxed paper under different storage conditions during 2019 and 2020 seasons. Moreover, the interaction between the studied treatments and storage periods had a significant effect on increasing juice weight.
5.1.1.3. Juice volume of 100 g arils
There was a decrease in juice volume in all treatments during both storage conditions in the two studied seasons. Cold conditions were more effective in delaying the deterioration of juice content than room conditions. All tested treatments had a significant effect on maintaining juice volume of arils compared to untreated fruits. Turmeric oil and ginger oil in combination with waxed paper were the best treatments which gave the highest values of juice volume under room and cold storage conditions during the various seasons of the study. The interaction between the studied treatments and storage periods had a significant effect of all treatments on preserving juice content of arils.
5.1.2. Chemical properties
5.1.2.1. Total soluble solids percentage (TSS %)
Total soluble solids percentage was increased with prolonging the storage period. Moreover, low temperature had the best effect on reducing changes of total soluble solids percentages compared to the room conditions. All treatments significantly decrease the total soluble solids percentage compared with control. On the other hand, in 2020 season under cold storage, there was no significant difference between ginger oil treatment and control (untreated fruits). The lowest values of total soluble solids were scored using turmeric oil plus waxed paper and ginger oil plus waxed paper under room and cold storage conditions in the various studied seasons. Moreover, the interaction between storage treatments and storage periods had a significant effect on reducing changes in total soluble solids.
5.1.2.2. Total acidity percentage (TA %)
In general, the total acidity percentage of juice was gradually decreased by the prolonging the storage duration under both storage conditions during two seasons of the study. Moreover, cold storage had the best effect for reducing changes in total acidity content compared to room conditions. All the studied treatments caused a significant increase in juice acidity percentage compared with untreated fruits. Using turmeric oil plus waxed paper and ginger oil plus waxed paper gave the maximum values compared to other treatments and control under both storage conditions during the two studied seasons. There was a significant effect of interaction between tested treatments and storage periods on reducing changes in acidity.
5.1.2.3. Reducing sugars percentage
Reducing sugar percentage of fruits was significantly increased by extending the storage period in both seasons of the investigation. Moreover, cold storage had the best effect for reducing changes in reducing sugar content compared to room conditions. All tested treatments led to a significant effect on decreasing changes of reducing sugar content in stored fruits compared to control. Combined turmeric oil or ginger oil with waxed paper led to significantly lowest values of reducing sugar under room and cold storage conditions during 2019 and 2020 seasons. There was a significant effect of interaction between the studied treatments and storage periods on decreasing reducing sugar percentage.
5.1.2.4. Total Anthocyanin content
There was a significant increase in anthocyanin content from the beginning of storage till its end. All treatments led to a significant decrease in total anthocyanin content compared to control (untreated fruits). The lowest values were due to combined turmeric oil or ginger oil with waxed paper. Moreover, there was a significant effect of interaction between the studied treatments and storage periods on reducing an increase of total anthocyanin content.
5.2. Conclusion
On the light of obtained results of this study, it could be concluded that coating with essential oils (turmeric oil and ginger oil) and wrapping with waxed paper maintained the quality of Manfalouty pomegranate fruits for 8 weeks under room temperature and 20 week under cold storage. Moreover, the combination between turmeric oil or ginger oil and waxed paper was more effective and gave the best results on keeping fruits quality for the longest possible storage period.