The investigation of the fingerprint components of some commercial grapes cultured in Turkey

The grape is the fruit of the vine plant whose genus name is Vites in botany. Within the scope of this research, stems, seeds and fleshy parts of the 8 grape varieties (Rooster, Alphonse lavallee, White sergeant, Mevlana, Michele Palieri, Sultani seedless, Redglobe, Mariana red) grown in Turkey were investigated for their resveratrol and other phenolic compounds along with their antiradical activities. After dried each part, the stalk, seed and fruit of the grapes were grinded and each extracted with the solvent mixture of methanol: water (90:10) at room conditions. Using the same solvent system, the stalk, seed and fruit of the grapes extracts were also prepared in an ultrasonic bath environment. The extracts obtained by both methods were analyzed using previously validated phenolic compounds with HPLC-DAD. Phenolic components including resveratrol were determined in the parts of grape varieties of Roosterblack, Alphonse lavallee, White Sergeant, Mevlana, Michele palieri, Sultani seedless, Redglobe, Mariana red. In the analysis resulted that the amount of phenolic components were high in the extarcts of stems and seeds of 7 varieties (Alphonse lavallee, White sergeant, Mevlana, Michele Palieri, Sultani seedless, Redglobe, Mariana red) in the maceration method. In the ultrasonic bath assisted extraction method, it was observed that the amount of phenolic components was higher than that of extracts obtained by maceration method. Especially in the seeds of the Roosterblack, Alphonse lavallee, White Sergeant, Mevlana, Michele Palieri, Redglobe, Mariana red grape varieties and in the stem of Alphonse lavallee, White Sergeant, Mevlana, Michele Palieri, Sultani seedless, Mariana red grape varieties, the amounts of phenolic components were higher in the extracts obtained by ultrasonic method. Unfortunately, in both methods, less phenolic components were detected in the fruit parts of the grapes. The highest amount of resveratrol was detected in the stem of Redglobe grape. The stem and seed extracts of Horozkarası grape obtained by maceration method also had a high amount of resveratrol. Resveratrol was not found in the seeds of Redglobe, Alphonse lavallee, Michele Palieri, and Mariana red grapes. The antiradical activity of the extracts obtained by both methods decreases in the following order of the seeds, stems and fruits, respectively. While the seeds and stems competed with the standard antioxidants, it was observed that the antioxidant capacity of the fruits was low. By investigating the changes of the compounds in the fruit, seed and stem, it was revealed whether there are new potential compounds and activities from the wastes of the grapes. The study reveals that satudied grapes, which are traded, contain potential antioxidant substances in their stems, although not as much as the seeds, and it can be evaluated with further studies in this area. Keywords: Grapes, Resveratrol, HPLC-DAD, Phenolic Components, Antiradical Activity