Effect of Cluster Thinning and Prohexadione Calcium Applications on Phenolic Composition and Sensory Properties of Red Wines

Abstract

The overall objective of this study was to investigate the effect of manual cluster thinning (CT) and the application of the growth regulator Prohexadione calcium (ProCa) on the phenolic composition and the sensory profile of Tempranillo and Grenache wines produced from treated vines in La Rioja (Spain). ProCa was applied at preblooming and CT was carried out at veraison in two consecutive years. Different physicochemical parameters and analyses of phenolic compounds were carried out in control, CT and ProCa grapes and wines and wine sensory was performed. Thinning treatments decreased crop yield, besides ProCa application reduced berry size, and berry weight. Color and phenolic composition of Grenache and Tempranillo wines in general were affected by thinning treatments, with an increase in anthocyanin, flavanol and flavonol concentrations. In sensory analysis, wines obtained from thinned vines presented higher values for several aromatic (e.g., white and yellow fruits, fresh flowers) and taste attributes (i.e., astringency, bitternes, persistence). CT and ProCa treatments resulted in an improvement in wine quality. In general, similar results in phenolic composition, sensory properties and quality of wines were obtained by manual and chemical cluster thinning. ProCa as a growth regulator may be an option for a quality vitiviniculture.

Phenylalanine and urea foliar applications to grapevine: Effect on wine phenolic content

“…Both pyranoanthocyanins tend to be formed during the fermentation by reactions between malvidin-3-O-glucoside and pyruvic acid (vitisin A) or acetaldehyde (vitisin B) (Bakker & Timberlake, 1997). Malvidin derivatives were found to be the predominant anthocyanin type, while p-coumaroyl anthocyanins were the major acylated form, which is in accordance with previous studies with Tempranillo grape variety (Avizcuri-Inac et al, 2013;Diago, Ayestarán, Guadalupe, Garrido, & Tardaguila, 2012). Table 1 Oenological parameters of control wine and wines made from grapevines treated with different doses (1: 0.9 kg N/ha; 2: 1.5 kg N/ha) of phenylalanine (Phe) and urea (Ur).…”

“…Additionally, it was also possible to detect the 3-O-glucuronides of myricetin and quercetin. As seen in previous studies with Tempranillo grape variety (Avizcuri-Inac et al, 2013;Diago et al, 2012;, quercetin and myricetin derivatives were the major flavonols in wine accounting for around 90% of total flavonols (Table 3).…”

Effect of Shoot and Bunch Density on Yield and Quality of ‘Sugraone’ and ‘Thompson Seedless’ Table Grapes

“…The response is a consequence of the greater availability of photoassimilates directed to clusters in plants showing lower density. However, high bunch thinning intensity may reduce yield (FANZONE et al, 2011;AVIZCURI-INAC et al, 2013). It should be emphasized that these responses are influenced by different components of the production system.…”

“…Avizcuri-Inac et al (2013) considered that the intensity of these responses is affected by other factors that influence growth and production. These authors exemplified that deficiencies in fruiting as a consequence of restrictive climatic conditions may limit the expected benefits to the quality of the grapes and / or their derivatives when bunch thinning is adopted.…”

“…Thus, the synthesis of DOI 10.1590/0100-29452017 828 Jaboticabal -SP PATRÍCIA COELHO DE SOUZA LEÃO & MARIA AUXILIADORA COELHO DE LIMA stilbenes, isoflavones, phenolic acids and flavonoids are induced by the regulation of specific genes, which are activated after bunch thinning, inducing transcriptomic changes in berries, especially at the end of the stage that delimits changes in color and softening of grapes (PASTORE et al, 2011). Avizcuri-Inac et al (2013) pointed out that different grapevines respond differently to bunch thinning. The authors reported higher anthocyanin and tannin phenolic contents in grapes harvested from plants submitted to bunch thinning.…”