Determination of phenolic materials contents of some local grape varieties growed in Bilecik

In this study, it was aimed to determine the physical and chemical properties and phytochemical properties of 7 local grape varieties (Ağ Üzüm, Alibeyli, Böğrül, Eski Kara, Kartal Çavuş, Recep Sert and Yeşil Tiryaki) in Bilecik province. Within this scope, bunch weight, bunch stem length, bunch shape, bunch density, grain shape, grain weight, grain width, grain size, breaking strength from the stem, grain hardness, grain color values, water-soluble dry matter amount, total acidity amount, maturity index, pH value, total phenol amount, antioxidant activity, glucose, fructose, total sugar and glucose/fructose ratios of grape varieties were investigated. When the total phenol values are analyzed, it is determined that, Kartal Çavuş (129.98 mg GA/100 g), Ağ Üzüm (129.75 mg GA/100 g), Eski Kara (129.58 mg GA/100 g) and Yeşil Tiryaki ( 128.5 mg GA/100 g) were observed that the total phenol content of grape cultivars /100 g) was quite high. The cultivar with the highest value in terms of antioxidant content was Eski Kara (68.05 μmol TE/g), followed by Recep Sert and Kartal Çavuş, respectively. It is observed that the glucose/fructose ratios of local varieties vary between 0.92 (Eski Kara) and 0.98 (Kartal Çavuş). When all the results are analyzed; It has been observed that Kartal Çavuş, Ağ Uzum, Eski Kara, Yeşil Tiryaki have values close to or higher than commercial varieties in terms of phenolic properties and antioxidant capacity. It is thought that these grape varieties can be used as a natural antioxidant source in the food and pharmaceutical industry by promoting their production due to their content. On the other hand, in the study conducted on 7 different local grape varieties of Bilecik province, some varieties were found to have commercial value. By recommending the production of local varieties with high table quality in terms of grain and cluster characteristics, the production of the local people can be encouraged commercially.