Morphological, quality characteristics, and antioxidant activity of grapes from heritage germplasm grown in Central Anatolia, Turkey

Abstract

Conservation of Central Anatolian grapevine genetic resources is essential to slow down to loss of biodiversity and genetic resources. This study provided information about fruit quality characteristics including morphological, physical, chemical, and antioxidant potential of ten grape accessions from heritage germplasm grown in Central Anatolia. Physical and chemical quality characteristics measured included berry and cluster weight, must yield proportion, firmness and chroma index, pH, titratable acidity (TA), total soluble solids (TSS), total anthocyanins (TAC), total phenolics (TP) and total flavonoids (TF). Also, antioxidant potential of ethanolic berry extracts were investigated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric ion reducing antioxidant power (FRAP) assays. ‘Kızıl Üzüm, ‘Nuniyar’, ‘Karaşabı’ and ‘Kırmızışabı’ had higher firmness values and lower must yield, which are important for storage of table grapes. ‘Kavak yaprağı' had heaviest berries, highest must yield and TSS/TA ratio giving it excellent flavour. The red grape accession with the highest TAC was ‘Kırmızışabı’, and the highest TP and TF were recorded for ‘Sergi Karası’. Eighty percent of the extracts could scavenge 50% of the DPPH free radical with 0.28 mg mL-1 of extract. ‘Tilki Kuyruğu’ had the highest DPPH free radical scavenging activity due to high phenolic and flavonoid content. FRAP reducing power of extracts also showed a similar trend to DPPH free radical activity. The accessions with rich secondary metabolite profiles inhibited DPPH free radicals and increased FRAP activity. Based on these findings, it is possible to suggest that chemical characteristics including secondary metabolite profile and antioxidant activity of grapes might be used as biochemical marker to discriminate grape cultivars each other. Finally, the region where this study was carried out is very rich in grape diversity, it should be screened and valuable accessions protected for the future.