Phenolic compounds, favorable oxi-redox activity and juice color of ‘Concord’ grapevine clones

• Six clones of the ‘Concord’ grape were evaluated on three different rootstocks.
• The clone ‘202’ stood out for presenting higher means of total polyphenols and tannins, color intensity and higher intensities of yellow and red color.
• The rootstocks influenced the concentrations of phenols and color of the juice samples.
• The rootstock ‘420-A’ increased values of total phenols, tannins and oxy-redoxf activity of juice samples, while the ‘IAC 572’ provided a reduction in the intensity of the juice color.

The aim of this study was to evaluate the total phenols, anthocyanins, tannins, favorable oxi-redox activity (oxi-redoxf) and juice color of six clones of the ‘Concord’ grapevine on three rootstocks. Samples of juice obtained from ‘Concord’ clones ‘22’, ‘28’, ‘49’, ‘202’, ‘211’ and ‘225’ grafted onto ‘IAC 766’, ‘IAC 572’ and ‘420-A’ were evaluated. The trial was conducted at the Technology Center of COROL Cooperative, Rolândia, PR, Brazil. A completely randomized design was used as the statistical model, arranged in a factorial system (6 clones × 3 rootstocks) with three replications. The grapevines were trained in an overhead trellis system spaced at 4.0 m × 2.0 m, and the evaluations were performed at the 2010/2011 harvest. The juice samples were prepared using the Welch process. The juice from ‘Concord’ clone ‘202’ presented higher means regarding to total phenols and tannins, color intensity and yellow and red color at 420 and 520 nm. The juices did not differ significantly among themselves (P > 0.05) with regard to the oxi-redoxf activity, anthocyanins and violet color at 620 nm, however, the use of rootstock ‘420-A’ resulted in higher means for total phenols, tannins and oxi-redoxf activity, whereas ‘IAC 572’ resulted in a reduction in the color intensity of the juice.