Effects of Cultural Practices on Total Phenolics and Vitamin C Content of Organic Table Grapes
B. Isci1, Z. Gokbayrak2*, N. Keskin3
The total phenolic and vitamin C contents of organic table grapes were determined by spectrophotometry
and HPLC, respectively, after several quality-increasing treatments were applied at véraison for two
growing seasons. Cane girdling and cluster-berry thinning resulted in different responses in the cultivars.
‘Red Globe’ generally was found to produce the lowest quantity of total phenolics in the berries, while
‘Trakya Ilkeren’ was the cultivar that accumulated the highest phenolics. Vitamin C accumulation in
the berries was also affected by the treatments. The effect of the treatments was inconclusive in ‘Buca
Razak?s?’. The application of both girdling and thinning caused more accumulation of vitamin C in the
‘Alphonse L.’ and ‘Trakya Ilkeren’ berries.
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