Phenolic compounds and antioxidant activity of red and white grapes on different rootstocks

This study aimed to assess the rootstocks influence over total phenolic compound content, antioxidant activity and its correlation in different red and white grapes cultivars for wine production. This study conducted an experimental three-year-old vineyard, located in Jundiai, in the State of Sao Paulo, Brazil, from July 2013 to January 2014. Red and white grapes from Vitis vinifera L. (Cabernet Sauvignon, Cabernet Franc, Merlot, Syrah and Sauvignon Blanc), V. labrusca L. (Isabel and Bordo) and hybrid cultivars (IAC 138-22 Maximo, BRS Violeta, IAC 116-31 Rainha, IAC 21-14 Madalena and BRS Lorena) were grafted on IAC 766 and 106-8 Mgt rootstocks. Samples of grapes were collected and the total carotenoids, chlorophyll, anthocyanin, flavonoid, and phenolic content, and the in vitro antioxidant activity determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method. The rootstocks effects on red grape were mainly observed on the anthocyanins content. The total polyphenols content and the grapes antioxidant activity was virtually not affected by the rootstocks, especially on grapes of BRS Violeta and IAC 138-22 Maximo kinds, which presented the highest content of this compost. Among the white grapes, the 106-8 Mgt rootstock favored the increase of total phenolic compounds content on grapes of Sauvignon Blanc, IAC 116-31 Rainha and IAC 21-14 Madalena kinds. Although the hybrid grapes of IAC 116-31 Rainha e IAC 21-14 Madalena kinds are white grapes, the total phenolic compounds content on them were higher than the ones found on the red grape Isabel.   Key words: Vitis vinifera, Vitis labrusca, hybrid grapes, total anthocyanin, Folin-Ciocalteau, 2,2-diphenyl-1-picrylhydrazyl (DPPH).