Regulador vegetal e bioestimulantes na influência da composição fenólica e características cromáticas nas uvas e vinho das CVS. 'Cabernet Sauvignon' e 'Merlot'

Abstract

The management of vineyards is essential for maintaining the phenolic quality of fine red wines. It is known that the accumulation of anthocyanins is regulated, at least in part, by abscisic acid, and the exogenous applications of this hormone increase the concentrations of anthocyanins and phenolic compounds in the grape, as well as in wine. The application of biostimulants derived from algae extract and plant extracts can be an alternative for the organic management of the vine. The objective of this work was to verify the effect of the application of biostimulants such as abscisic acid, Ascophyllum nodosum extract (L.) and Aloe vera gel on the phenolic quality of grape and wine. Thus, this study consisted of 7 treatments, including 2 concentrations of abscisic acid, Ascophyllum nodosum or Aloe vera gel, in addition to the control (without treatment). The experiment was carried out in a commercial winery in Campo Largo - PR, for two consecutive harvests (2017/18 and 2018/19), with two cvs. Merlot and Cabernet Sauvignon. Two applications were performed for seaweed extract and Aloe vera gel, when the bunches had 50 and 75% of the berries with coloration. For S-ABA, a single application was performed when the bunches presented 50% of their berries with coloration. The evaluations were as follows: content of anthocyanins and total polyphenols and; activity of the enzymes phenylalanine ammonia lyasis, polyphenoloxidase and peroxidase in the epidermis. For the wine, in addition to the content of anthocyanins and total polyphenols, individual color and anthocyanin analysis and antioxidant activity were performed. For the cv. Cabernet Sauvignon, the applications of S-ABA increased the content of anthocyanins and total polyphenols, and the activity of FAL, in the epidermis and Ascophyllum nodosum. increased phenolic parameters in wine. A.vera gel influenced the color of the wine. For the cv. Merlot, S-ABA increased the content of anthocyanins and total polyphenols, and FAL activity in the epidermis of grapes, also increasing the quantification of monomeric anthocyanins in wine. Ascophyllum nodosum 0.4 mL L-1 under field conditions increased total polyphenols and anthocyanins. Treatment with A. vera at 400 mg L-1 had a positive effect on the increase in total polyphenol contents and PPO enzyme activity. For the analyses of the wine, treatments with A. vera gel and A. nodosum extract increased the total anthocyanin content and antioxidant activity.