Enhancing Phenolic Maturity of Syrah with the Application of a New Foliar Spray

Abstract

68Several technological applications can be used in order to reduce these negative effects. 69Cluster thinning (Guidoni et al., 2002; Prajitna et al., 2007), girdling (Singh Brar et al., 2008; 70 Koshita et al., 2011) and early defoliation (Poni et al., 2006; Poni et al., 2009; Kemp et al., 2011; variety, fungal infections and yield (Jeandet et al., 1995; Bavaresco 2003; Bavaresco et al., 2007; 75 Prajitna et al., 2007). There are also some paper which are dealing with increasing resveratrol 76 concentration in grapes using elicitors (Vezzulli et al., 2007; Santamaria et al., 2011). accumulation is very fast at the Nagy-Eged-hill, leading too alcoholic, unbalanced wines. 91Besides, the desired level of phenolic maturity cannot be achieved in most of the vintages. The Three one kg samples for each treatment were collected at random from several clusters before 121 vinification. The berries were selected randomly from the upper, middle, and lower parts of the 122 bunches. All the berry samples were prepared and analyzed within 2 hours after the harvest. juices was determined at 20 °C using a hand-held refractometer (Atago MASTER-α, Japan). 137 Assesment of grape phenolic maturity 138The phenolic potential of grapes was calculated according to the method described by with their pedicel were removed from the bunch, they were laid on the plate of the analyzer and 158 then they were punctured in the lateral face (Letaief et al., 2008a). The skin break force (F sk ), 159 skin break energy (W sk ) and Young's modulus of berry skin (E sk ) were calculated from the 160 puncture test data using the software Exponent 6.1.4.0. Berry skin thickness (Sp sk ) was measured 161 using a P/2 probe with 2 mm diameter. For this measurement, approximately 0.25 cm 2 skin was 162 removed from the lateral face of the berry. The skin was carefully and gently cleaned of pulp, and 163 then placed on the platform and the test was conducted as described by other authors previously 164( Letaief et al., 2008a; Letaief et al., 2008b; Río Segade et al., 2008

Effects of foliar application of inactivated yeast on the phenolic composition of <em>Vitis vinifera</em> L. cv. Agiorgitiko grapes under different irrigation levels

“…34 In contrast, Villangò et al observed, under cooler climate conditions, a positive or no significant effect of foliar yeast sprays on pigment accumulation across different harvest dates and experimental years, and they consistently found a higher anthocyanin extract- ability in sprayed grapes. 36 Differences between the latter work and our results could be related to the differences in climatic conditions and vine water relations between the two regions; it is possible that under the semiarid conditions of Greece, water conditions had a more marked influence on berry secondary metabolism, 27 masking the effects of yeast derivative application. Moreover, the decreased phenolic content per berry under yeast application in the present study, is possibly related to the thinner skins of treated berries since anthocyanin and total phenol concentrations (mg/g BW) were similar between sprayed and non-sprayed vines.…”

“…36 Application of yeast derivatives had no effect on must sugar concentration, pH or TA in accordance with Portu et al, 34 while Villangò et al reported variable effects of yeast derivative spray on grape TA and pH across different harvest dates and vintages. 36 Foliar spraying had no effect on total anthocyanin and total phenol content per g of BW, in accordance with previous studies under similar climatic conditions. 34 Yeast application had no impact on individual anthocyanin composition of berry skins, with the exception of Dp, the levels of which were increased by yeast application.…”

“…34 Yeast application did not influence skin and seed tannin concentration, as also reported by Portu et al 34 Similarly, Villangò et al found no effect of foliar spray on seed maturity. 36 Yeast application had no effect on alcohol concentration, TA or pH of the wines produced. The same result was reported by Portu et al in Tempranillo 34 and Villangó et al in Syrah.…”

“…The same result was reported by Portu et al in Tempranillo 34 and Villangó et al in Syrah. 36 There was also no impact on color intensity or color hue. 34 In accordance with the results of grapes, foliar yeast spraying had no influence on anthocyanin composition of the wines.…”

Evaluation of Grenache, Graciano and Tempranillo grape stilbene content after field applications of elicitors and nitrogen compounds

“…Similarly, applications of MeJ directly to the clusters also increased total stilbenes in Barbera, Monastrell and Syrah . As for the application of YD, the same commercial spray was applied to Syrah grapevines in Hungary . These authors observed that, although stilbene synthesis was enhanced in the earlier phases of ripening, the effect was less pronounced depending on the commercial harvest date.…”