Search

The main purpose of this study is to determine the contents of 3 major phenolic compounds (gallic acid, catechin, and epicatechin) in 22 different grape cultivars/hybrids obtained from 2 different breeding programs. Additionally, changes in these phenolic components in the grape leaves of some resistant/tolerant species were determined in relation to powdery and downy mildew diseases in viticulture. The skin, pulp, and seeds of grape berries were analysed over two years, while changes in the phenolic contents of grape leaves were determined before and after these diseases for two years. The major phenolic contents of new hybrids/cultivars were compared with those of popular cultivars in different parts of the grapes, and significant differences in phenolic contents were found among hybrids/cultivars and different grape parts. Variations in the contents of phenolics in grape seeds, skins, and pulp were high, but seeds contained higher levels of these phenolics than pulp and skin. Analyses of the relationship between two viticultural diseases and phenolic changes in resistant/tolerant cultivars in relation with the susceptible “Italia” cultivar revealed that an increase in the content of the phenolic compounds was found after powdery mildew disease. Hybrids/cultivars with high phenolic contents are recommended to develop new superior cultivars, which are resistant to grape fungal diseases, in breeding programs.

Amaç: Bu çalışmada farklı türlere mensup üzüm çeşit/genotiplerinin külleme ve mildiyö hastalıkları sonrasında yapraklarındaki bazı fenolik madde değişimleri iki yıl süre ile incelenerek hastalıklara dayanıklılık ile bu bileşenler arasındaki ilişki incelenmiştir.Materyal ve Metot: Çalışmada 2 V. labrusca genotipi, 11 V. vinifera çeşit/genotipi ve 2 türler arası melez çeşit ile çalışılmıştır. Çeşit/genotiplere mildiyö ve külleme hastalığı suni inokülasyon ile uygulanmış ve akabinde, hastalık öncesi ve sonrasında alınan yaprak örneklerindeki toplam fenolik madde miktarı (spektrofotometrik), antioksidan aktivitesi (spektrofotometrik), rutin (HPLC) ve klorogenik asit (HPLC) değişimleri incelenmiştir.Bulgular: Üzüm çeşit ve genotiplerinde mildiyö ve külleme hastalıkları sonrasında toplam fenol miktarı ile antioksidan aktivitesinde ciddi artışlar görülmesine karşılık; rutin ve klorogenik asit miktarlarında ise çeşit veya genotipe ayrıca hastalığa bağlı olarak farklılıklar görülmüştür. Çalışma sonucunda FX1-1 genotipi hastalıklara dayanıklılığı ve farklı fenolik bileşenleri yüksek miktarda içermesi sebebiyle dikkat çekici bulunmuştur.Sonuç: Benzer pek çok çalışmada olduğu gibi özellikle toplam fenol miktarı ve antioksidan aktivitesinde hastalıklar sonrasında ciddi artışlar olduğu görülürken diğer bileşenlerdeki artışların değişkenlik gösterdiği sonucuna ulaşılmıştır. Çalışmada kullanılan çeşit/genotiplerin büyük bir kısmının hastalık inokülasyon sonuçlarına göre dayanıklı ve tolerant oldukları belirlenirken sınırlı sayıda çeşit/genotipin ise özellikle külleme yönünden hassas oldukları tespit edilmiştir. Bundan sonraki çalışmalarda toplam fenol miktarı ve antioksidan aktivitesindeki artışlar üzerine yoğunlaşarak neden arttıkları ve hastalıklara dayanıklılıkta ne gibi etkileri olduğu konusunda kapsamlı çalışmalar yapılması yararlı olacaktır.

CELIK, HUSEYIN -/0000-0003-1403-7464 WOS: 000396338300008 Powdery mildew and downy mildew are among the most important diseases of grapevine. The relationship between these diseases and phenolic components has become increasingly important in recent years. This study evaluated changes of total phenolics, total antioxidant activity, and phenolic compounds (gallic acid and rutin hydrate) in some Vitis species. Vitis labrusca cultivars or genotypes, Vitis vinifera cultivars, interspecies hybrids, and a Vitis rotundifolia cultivar's healthy and infected leaves were examined. The contents of healthy material and of samples of plant material infected with both microorganisms (Uncinula necator (Schw.) Burr and Plasmopara viticola (Berk. & M. A. Curtis) Berl & De Toni) were determined. In general, the content of all compounds, except rutin hydrate, increased in infected leaves. After infection with powdery mildew, the increase was particularly significant. The total phenolic content rose after infection but varied with the cultivar and species. The highest antioxidant activity (598.96 mu M TE/100 g) and total phenolic levels (2248.27 mg GAE/100 g) were identified in V. vinifera 'Italia', which is known to be sensitive to fungal diseases. On the other hand, the highest levels of gallic acid (9.26 mg/100 g) were identified in V. rotundifolia 'Sugargate', which is known to be resistant to fungal diseases. The highest levels of rutin hydrate (60.44 mg/100 g) were identified in V. vinifera 'Red Globe'. There was a significant positive correlation between total phenolics and total antioxidant after both diseases (0.7556-0.6904). Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [113O641] The authors are grateful to the Scientific and Technological Research Council of Turkey (TUBITAK, project number 113O641) for funding.

Total phenolic contents and antioxidant activities of pulp, seed and skin of 22 grape varieties (7 white and 15 red) grown in the Marmara region of Turkey were determined (common, registered or candidate cultivars). The total phenolic contents of grape pulp, seed and skin parts ranged from 9.26 to 62.29, from 162.29 to 326.18 and from 96.61 to 167.42 mg gallic acid equivalents/100 g fresh weight, respectively. Seasonal changes were noticeable in the total phenolic contents and antioxidant activities of different grape parts. The antioxidant activity of grape seeds of registered or candidate cultivars was the highest, followed by skins and pulps. The antioxidant activities of grape skins were higher in red varieties than in white varieties. The results indicated that registered and candidate red or white grape cultivars may have high amounts of phenolics and possess a superior antioxidant activity in comparison to popular cultivars, such as Bilecik Irikarasi, Hamburg Misketi, Alfons and Isabella. Practical Applications Grapes are an important commercial commodity because they can be consumed fresh or processed into many food products such as juice, jams, raisins and wine. Chemical properties of grapevines are one of the most important factors that determine the industrial use of grape berries. A great deal of diverse phenolic compounds is located in the skins, pulp and seeds of grapes. The antioxidant activity of different parts of grapes has been studied in popular and hybrid varieties; however, studies should also be continued on hybrid varieties to determine better grape berries with high antioxidant activity and phenolic content. Berries with better quality in terms of antioxidant activity may present great potential for the food industry as well as health-conscious consumers.