Document Details
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Document Type |
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Thesis |
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Document Title |
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Quality, Antioxidants and Enzymes Activity of Table Grapes as Affected by Cultivar, Developmental Stage, Growth Regulators and Storage الجودة، مضادات الأكسدة والنشاط الإنزيمي لثمار العنب وتأثرها بالصنف، مرحلة التطور، منظمات النمو والتخزين |
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Subject |
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Faculty of Meteorology, Environment and Arid Land Agriculture |
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Document Language |
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Arabic |
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Abstract |
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Grapes are considered as good source for bioactive antioxidants intake that largely contribute to human health. Changes in berry quality, antioxidant compounds, antioxidant capacity and enzymes activity during storage (0 oC ±1 and 90–95% RH plus 2 days of shelf life) of three local table grape cultivars ‘Hegazi’, ‘El-Bayadi’ and ‘Red Romy’ were evaluated. ‘El-Bayadi’ showed lower decay and weight loss percentage than other cultivars. Compared to initial, total soluble solids (TSS) content increased in ‘Red Romy’, fluctuated in ‘Hegazi’ and not changed in ‘El-Bayadi’ during storage. TSS was higher in ‘Hegazi’ than other cultivars. Titratable acidity (TA) was higher in ‘Red Romy’ and ‘El-Bayadi’ but lower in ‘Hegazi’ after storage than initial. Berry firmness decreased during storage and was higher in ‘El-Bayadi’ than other cultivars. Total phenols concentration of ‘Hegazi’ remained stable after 25 days but was higher after 40 days of storage than initial. In ‘Red Romy’, it was higher after 25 and 40 days of storage than initial, but remained stable in ‘El-Bayadi’. After 25 days of storage, ‘Red Romy’ showed higher total phenols than other cultivars. Total flavonoids concentration in ‘Hegazi’ and ‘El-Bayadi’ remained stable during storage, but was higher after 25 and 40 days of storage in ‘Red Romy’ than initial. Initially, total flavonoids was similar among cultivars, but was higher in ‘Red Romy’ after 25 and 40 days of storage than initial. trans-resveratrol concentration remained stable in ‘Hegazi’, fluctuated in ‘Red Romy’ and decreased in ‘El-Bayadi’ during storage. trans-piceid and vitamin C concentrations decreased during storage and were higher in ‘El-Bayadi’ than other cultivars. Antioxidant capacity (DPPH IC50) decreased during storage compared to initial with no differences among cultivars. While, antioxidant capacity (ABTS IC50 values) was lower after 40 than after 25 days of storage and initial. ‘Red Romy’ showed higher antioxidant capacity than other cultivars. Peroxidase (POD), polyphenoloxidase (PPO) and polygalacturornase (PG) activities greatly changed among cultivars and during storage. Changes in berry quality, antioxidant compounds, antioxidant capacity and enzymes activity during storage of imported table grape cultivars (‘Red Globe’ from Lebanon, South Africa and Italy, ‘Michele Palieri’ (Italy), ‘Barlinka’ (South Africa), ‘Thompson Seedless’ from South Africa and Italy, ‘Melissa’ (Spain) and ‘Seedless Sugraone’ (Italy)) marketed in Saudi Arabia were evaluated. Great variations in regular quality attributes (decay, weight loss, firmness, TSS and TA) were detected during storage and among cultivars. Vitamin C concentration increased during storage in ‘Melissa’ but it remained stable in ‘Red Globe’ (South Africa), ‘Barlinka’, ‘Thompson Seedless’ (South Africa) and ‘Seedless Sugraone’. ‘Michele Palieri’ and ‘Red Globe’ (Italy) showed the highest vitamin C during storage. Total phenols concentration increased during storage in all cultivars except for, ‘Red Globe’ (Lebanon), ‘Melissa’ and ‘Seedless Sugraone’. ‘Red Globe’ from both Lebanon and Italy and ‘Michele Palieri’ showed the highest phenols concentration. Total flavonoids concentration increased during storage in ‘Red Globe’ (South Africa), ‘Michele Palieri’, ‘Barlinka’ and ‘Thompson Seedless’ (South Africa) but it remained stable in ‘Thompson Seedless’ (Italy) and ‘Seedless Sugraone’. After 20 and 35 days of storage, ‘Red Globe’ (Lebanon) showed higher total flavonoids concentration than other cultivars, but ‘Michele Palieri’ gave the highest after 50 days of storage. trans-resveratrol concentration sharply decreased during storage in ‘Barlinka’ but it remained relatively stable in ‘Red Globe’ (Lebanon), ‘Thompson Seedless’ (Italy), ‘Melissa’ and ‘Seedless Sugraone’ and fluctuated in ‘Red Globe’ (South Africa). After 20 days of storage, ‘Barlinka’ showed the highest trans-resveratrol concentration while, ‘Red Globe’ (South Africa) was the highest after 35 days of storage. After 50 days of storage, ‘Michele Palieri’ retained higher trans-resveratrol concentration than other cultivars. trans-picied concentration decreased during storage in ‘Red Globe’ (South Africa), ‘Barlinka’, ‘Melissa’ and ‘Seedless Sugraone’ but it fluctuated in ‘Red Globe’ (Italy), ‘Michele Palieri’ and ‘Thompson Seedless’ (Italy). While, in ‘Red Globe’ (Lebanon), it remained relatively stable until day 35 and then increased at the end of storage. After 20 and 35 days of storage, ‘Barlinka’ showed the highest trans-picied concentration. While, after 50 days of storage, ‘Red Globe’ (Lebanon) and ‘Michele Palieri’ gave higher trans-picied concentration than other cultivars. Antioxidant capacity (IC50 value) estimated by DPPH and ABTS assays decreased (higher IC50 value) during storage in most cultivars but remained stable with fluctuation in some others. Antioxidant capacity greatly varied upon cultivar and assay method. Peroxidase, polyphenoloxidase, polygalacturornase and xylanase enzymes activity greatly varied during storage and among cultivars. Nitrogen and protein percentages were higher in ‘Barlinka’ while, potassium was higher in ‘Red Globe’ (Italy) and ‘Seedless Sugraone’ than other cultivars. The correlation coefficients among the measured parameters were evaluated and discussed. In two successive seasons 2014 and 2015, changes in phenolic compounds, antioxidant capacity and enzymes activity in ‘El-Bayadi’ table grape skin during development were evaluated. The growth of berries followed a typical double sigmoid curve, and veraison stage corresponded to the inception of the slow growth phase. Total phenols concentration gradually decreased during berry development reaching 0.67 and 1.34 g Kg-1 at ripening stage for 2014 and 2015 season, respectively. Total flavonoids concentration gradually decreased during growth with a slight increase at ripening stage reaching 0.59 and 0.38 g Kg-1 for 2014 and 2015 season, respectively. Total phenols concentration showed higher values in 2015 than 2014 season, in contrast to total flavonoids. Both trans-resveratrol and trans-picied concentrations were highest early in the season, but gradually decreased during growth with an increase during ripening, representing 0.28 and 0.26 mg Kg-1 for trans-resveratrol, and 1.39 and 1.12 mg Kg-1 for trans-picied, for 2014 and 2015 season, respectively. The level of trans-picied was much higher than that of trans-resveratrol during growth and ripening in both seasons. Antioxidant capacity gradually increased (lower IC50 values of DPPH and ABTS) during growth and ripening. Peroxidase (POD) activity gradually increased to a peak at veraison with a slight fluctuation during ripening. While, polyphenoloxidase (PPO) activity initially increased, slightly fluctuated and then decrease during ripening. Polygalacturonase (PG) activity gradually increased to a maximum at 20 days after veraison and, then decrease at ripening. While, xylanase activity was highest early in the season, but sharply decreased during growth and, then increased during veraison and ripening. Berry quality, antioxidant compounds, antioxidant capacity and enzymes activity of ‘El-Bayadi’ table grapes cultivar at harvest as affected by preharvest spray of salicylic acid (SA, 4.0 mM) and gibberellic acid (GA3, 30 mg/L) were evaluated during 2014 and 2015 seasons. GA3 spray increased berry weight, length and width compared to SA and control treatments. SA spray decreased berry length and width compared to control. Both cluster weight and length increased by SA and GA3 compared to control. TSS content was not affected by treatments, but was higher in 2015 than 2014 season. TA was higher at GA3 and SA treatments than control and was higher in 2014 than 2015 season. TSS/acid ratio was lower at SA than GA3 and control treatments. Berry firmness was lower at SA than GA3 and control treatments and was higher in 2014 than 2015 season. Total phenols and flavonoids concentrations were higher at SA and GA3 treatments than control. trans-resveratrol concentration increased, while trans-piceid decreased by SA spray compared to GA3 and control treatments. Total phenols concentration was higher in 2015 than 2014 season, in contrast to total flavonoids and trans-resveratrol. Vitamin C concentration increased by GA3 spray compared to SA and control and was higher in 2015 season than 2014. Peroxidase (POD) polyphenoloxidase (PPO), polygalacturonase (PG) and xylanase activities increased by GA3 spray compared to SA and control. While, SA spray decreased both POD and PPO activities compared to control. Both SA and GA3 spray lowered antioxidant capacity (higher DPPH IC50 values) than control. Nitrogen, phosphorus and potassium, and protein concentrations were higher at SA and GA3 treatments than control. In conclusion, preharvest spray of SA and GA3 could be used to improve the overall quality ‘El-Bayadi’ table grapes. Such information might be useful for table grape breeders, growers, nutritionists and consumers. |
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Supervisor |
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Prof. Dr. Adel D. Al-Qurashi |
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Thesis Type |
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Doctorate Thesis |
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Publishing Year |
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1438 AH
2017 AD |
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Co-Supervisor |
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Prof. Dr. Mohamed A. Awad |
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Added Date |
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Thursday, June 8, 2017 |
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Researchers
| عبد العزيز محمد الراشدي | Alrashdi, Abdulaziz Mohammed | Researcher | Doctorate | |
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