Document Details
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Document Type |
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Thesis |
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Document Title |
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MODULATION OF RIPENING AND QUALITY OF BANANA FRUIT DURING SHELF LIFE WITH GUM ARABIC, PROPOLIS AND SALICYLIC ACID تعديل نضج وجودة ثمار الموز أثناء فترة العرض بالمعاملة بالصمغ العربي, البروبليس وحمض الساليسيليك |
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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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Banana (Musa spp) is one of the most commercially important tropical fresh fruit due to its especial flavor and nutritional properties as well as worldwide availability around the year. Bananas of most cultivars such as ‘Grand Nain’ are harvested at pre-climacteric full mature-hard green stage and thereafter ripening is triggered by exposing to a certain dose and duration of ethylene at about 18 oC and 85% RH in a commercial airtight ground warehouses. However, shelf life (SL) of post-climacteric bananas is relatively short (a few days) and fruit rapidly soften and deteriorate due to high metabolic activity with high respiration rate and ethylene production. Due to raising consumers concerns against the use of synthetic chemicals to modulate fruit ripening, several natural compounds are currently evaluated for their effectiveness on maintaining fruit quality during SL. In this regard, the effects of ethanolic extract of propolis (EEP) (2.5 or 5%) and gum Arabic (GA) (5 or 10%), as natural edible coatings, and salicylic acid (SA) (1 or 2 mM) as a safe natural signaling molecule and there combinations were evaluated for their impact on ‘Grand Nain’ bananas physiology as an attempt to modulate ripening process and retain quality during post-climacteric phase at ambient conditions for 9 days. The obtained results revealed that all the applied treatments significantly reduced weight loss after 6 and 9 days of SL. In this respect, EEP especially at low rate (2.5%) was the most effective followed by GA and SA. However, GA combined with SA or EEP were more effective in reducing weight loss compared to GA alone. While, the combination between EEP and GA gave similar effects to EEP alone. EEP and GA at both rates and EEP combined with GA or SA retained more green color and less yellow as estimated by peel color index and a* values of Minlota colorimeter, which reflect a delay in fruit ripening during SL compared to control. However, in this regard, SA at both rates showed similar peel color index and a* values of Minlota colorimeter as control. EEP and GA treatments at both rates delayed ripening of ‘Grand Nain’ bananas during SL as indicated by higher membrane stability index (MSI) of peel tissues, firmness and titratable acidity (TA) and lower total soluble solid (TSS) concentration and TSS/acid ratio, pH and peel browning than control especially after 6 and 9 days of SL. However, SA treatments showed little or no significant effects on firmness, TSS, TSS/acid ratio, pH, MSI, and peel color and browning indices during SL. Total phenols and flavonoids concentrations in both fruit peel and pulp fluctuated during SL and showed no consistent response to the applied treatments. However, as overall, both EEP and GA treatments retained higher total phenols and flavonoids levels in both peel and pulp especially after 3 and 6 days of SL, whilst SA showed no clear effects. As overall, vitamin C concentration in fruit pulp decreased during SL. However, all the applied treatments negatively affected vitamin C concentration of ‘Grand Nain’ bananas after 3 days but with no effects after 6 and 9 days of SL. Free radical scavenging capacity (FRSC) of both fruit peel and pulp increased (lower DPPH IC50 values) during SL. The decrease in total phenols, flavonoids and vitamin C concentrations with the increase in FRSC during SL suggests qualitative changes in antioxidant compounds during SL. Accordingly, parallel several assays should be used to investigate the principles of antioxidant/oxidation activity of a certain horticultural commodity. As overall, EEP and GA coatings, and SA at both rates effectively increased FRSC in fruit peel and pulp during SL compared to control. In the current study, both EEP, GA and SA treatments showed no consistent effects on the activities of the hydrolytic enzymes α-amylase, xylanase and polygalacturonase (PG) in fruit peel and pulp during SL, whilst EEP and GA treatments and the high rate of SA retained higher firmness than control only after 6 days of SL. GA, EEP and SA treatments increased the activity of the antioxidant enzyme peroxidase (POD) especially after 6 days of SL in both fruit peel and pulp. In addition, these treatments retained higher polyphenoloxidase (PPO) activity than control especially after 6 days of storage. It is concluded that EEP treatment especially at 2.5% or GA treatment especially at 5% retained quality of ‘Grand Nain’ bananas during SL and being suggested as natural alternatives to synthetic chemicals. |
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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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Master Thesis |
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Publishing Year |
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1439 AH
2018 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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Monday, July 16, 2018 |
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Researchers
| أحمد عبيد العلي | Alali, Ahmad Abid | Researcher | Master | |
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