Comprehensive Analysis of Cluster, Berry, Quality, and Phytochemical Traits in Grape Varieties from the Marmara Region of Türkiye

This study examined the physical, chemical, and phytochemical properties of 20 local grape varieties and 4 standard varieties grown under the ecological conditions of Marmara. The cluster weight of the varieties ranged from 82.50 g to 650 g, while the peduncle length of the primary bunch varied between 2.25 cm and 6.50 cm. Berry weight for the local varieties was observed between 2.08 g and 5.33 g, with berry width values ranging from 8.86 mm to 19.65 mm and berry length values from 11.46 mm to 24.13 mm. The breaking force from the stem was between 2.24 N and 4.05 N, and berry firmness values ranged from 3.66 N to 9.82 N. Regarding chemical composition, total soluble solids (TSS) values showed a minimum of 15.03% and a maximum of 22.25%. The titratable acidity of local varieties varied from 0.16 g/100 ml to 0.53 g/100 ml, and pH values ranged from 3.18 to 3.93. Furthermore, total phenolic content in local varieties was between 112.94 and 129.98 mg GA/100 g, with antioxidant levels ranging from 24.39 to 68.05 µmol TE/g. The glucose content ranged from 7.08 to 10.2 g/100 g, while fructose levels were between 6.95 and 10.38 g/100 g, and total sugar values ranged from 13.41 to 20.59 g/100 g. In conclusion, the wide variability in both physical and chemical properties among the examined grape varieties highlights the potential for selecting cultivars suited to specific ecological conditions and desired quality traits.