Phenolic composition of Tempranillo Blanco (Vitis vinifera L.) grapes and wines after biostimulation via a foliar seaweed application

Abstract

[Background] Seaweeds are defined as novel elicitors in many crops, allowing the synthesis of secondary metabolites to be triggered in different plant tissues. Currently, the phenolic composition of Tempranillo Blanco grapes and wines is unreported. The present study aimed to investigate the effects of an Ascophyllum nodosum seaweed extract applied to Tempranillo Blanco grapevines, at low (Ld) and high (Hd) dosages, on grape and wine phenolic compounds during two consecutive seasons (2017–2018). [Results] The results obtained showed that catechin was the most abundant phenolic compound in Tempranillo Blanco grapes and wines. Season affected the weight of 100 berries and some enological parameters. Catechin and flavonols concentrations in grapes were increased after Hd application to grapevines, independently of season. The concentration of hydroxycinnamic and hydroxybenzoic acids in wines was affected by vintage, probably as a result of oxidation reactions, as well as pinking phenomena, whereas the stilbenes content in wines was conditioned by the affect of cryptogamic diseases in grapes. [Conclusion] Seaweeds might act as an elicitor of several phenolic compounds in grapes, enhancing the content of some phenolic compounds in wines.