terclim by ICS banner
IVES 9 IVES Conference Series 9 EFFECTS OF LEAF REMOVAL AT DIFFERENT BUNCHES PHENOLOGICAL STAGES ON FREE AND GLYCOCONJUGATE AROMAS OF SKINS AND PULPS OF TWO ITALIAN RED GRAPES

EFFECTS OF LEAF REMOVAL AT DIFFERENT BUNCHES PHENOLOGICAL STAGES ON FREE AND GLYCOCONJUGATE AROMAS OF SKINS AND PULPS OF TWO ITALIAN RED GRAPES

Abstract

Canopy-management practices are applied in viticulture to improve berries composition and quality, having a great impact on primary and secondary grape metabolism. Among these techniques, cluster zone leaf removal (defoliation) is widely used to manage air circulation, temperature and light radiation of grape bunches and close environment. Since volatiles are quantitatively and qualitatively influenced by the degree of fruit ripeness, the level of solar exposure, and the thermal environment in which grapes ripen, leaf removal has been shown to affect volatile composition of grape berries [1].

The aim of this research was to assess the impact of vine defoliation on free and glycosylated VOCs (Volatile Organic Compounds) of two Italian red grapes: Nebbiolo (neutral) and Aleatico (semi-aromatic). Defoliation was performed at fruit set phenological stage for Aleatico grapevines, and for Nebbiolo also at berries touch.

Solid Phase Extraction/Gas Chromatography–Mass Spectrometry (SPE/GC-MS) was carried out to ana-lyse free and glycoconjugates VOCs isolated from skins and pulps as separate portions of the berries [2].

The results showed that defoliation had an almost negligible effect on free and glycosylated volatiles of Aleatico grapes, thus suggesting that defoliation at fruit set did not change the volatile composition of this grape variety. A different behaviour was observed for Nebbiolo grapes, on both free and bound VOCs, with a greater impact on the first. Indeed, all the 30 free VOCs identified were significantly (ANOVA; p<0.05) affected by defoliation and by the time at which it was carried out, with a greater influence on the skin components. Early defoliation at fruit set did not favour the accumulation of free VOCs in Nebbiolo skins, significantly reducing the content of several VOCs, such as n-butyl acetate, terpenes (α-terpineol, and nerol) and aldehydes (hexanal, and 2-hexanal). On the other hand, late defoliation performed at berries touch, reduced n-butyl acetate, but increased alcohols content (i.e., 3-methyl-1-butanol, 1-pentanol, 2-ethyl-1-hexanol, benzyl and phenylethyl alcohols), nerol, aldehydes (i.e., 2-hexanal), and vanillin.

Results suggest that the effects of defoliation at fruit set on the VOCs pattern is cultivar dependent and almost ineffective on Aleatico grapes. Moreover, early defoliation at fruit-set seems stressful for Neb-biolo grapes and its odorous and potentially secondary metabolites. These results can be useful to improve canopy and winemaking precision practices.

 

1. Poni et al., 2006. DOI: 10.5344/ajev.2006.57.4.397
2. Piombino et al., 2022. DOI: 10.1111/ajgw.12521

DOI:

Publication date: February 9, 2024

Issue: OENO Macrowine 2023

Type: Poster

Authors

Paola Piombino¹, Elisabetta Pittari¹, Alessandro Genovese², Andrea Bellincontro³, Osvaldo Failla⁴, Luigi Moio1, Fabio Mencarelli⁵

1. Department of Agricultural Sciences, Division of Vine and Wine Sciences, University of Naples Federico II, Avellino 83100, Italy
2. Department of Agricultural Sciences, Division of Food Science and Technology, University of Naples Federico II, Portici (NA), 80055, Italy
3. DIBAF, University of Tuscia, Via De Lellis, 01100 Viterbo, Italy
4. Department of Agricultural and Environmental Sciences, University of Milan, 20133 Milano, Italy
5. Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, Pisa 56124, Italy

Contact the author*

Keywords

defoliation, secondary metabolites, aromas

Tags

IVES Conference Series | oeno macrowine 2023 | oeno-macrowine

Citation

Related articles…

IMPACT OF THE WINES’ QUALITY ON THE WINE DISTILLATES’ ORGANOLEPTIC PROFILE

Brandy de Jerez (BJ) is a spirit drink made exclusively from spirits and wine distillates and is characterized by the use of casks for aging that previously contained Sherries. The quality and sensory complexity of BJ depend on the raw materials and some factors: grape variety, conditions during processing the wine and its distillation, as well as the aging in the cask. Therefore, the original compounds of the grapes from which it comes are of great interest (1 y 2) being in most cases the Airén variety. Their relationship with the quality of the musts and the wines obtained from them has been studied (3) and varies each year of harvest depending on the weather conditions (4).
Read More

Rootstock mediated responses of grapevine (Vitis vinifera L.) metabolism and physiology to combined water deficit and salinity stress in Syrah grafts

Water deficit and salinity are increasingly affecting the viticulture and wine industry. These two stresses are intimately related; understanding the physiological and metabolic responses of grapevines to water deficit, salinity and combined stress is critical for developing strategies to mitigate the nega- tive impacts of these stresses on wine grape production. These strategies can include selecting more tolerant grapevine cultivars and graft combinations, improving irrigation management, and using soil amendments to reduce the effects of salinity. For this purpose, understanding the response of grape- vine metabolism to altered water balance and salinity is of pivotal importance.

Read More

OENOLOGICAL TANNINS FOR PREVENTING THE LIGHT-STRUCK TASTE IN WHITE AND ROSÉ WINES

The light exposure of wine can be detrimental as a relevant loss of aromas takes place [1] and light-induced reactions can occur. The latter involves riboflavin (RF), a photosensitive compound, that is fully reduced by acquiring two electrons. When the electron-donor is methionine, the light-struck taste (LST) can appear leading to cooked cabbage, onion and garlic odours-like [2]. The use of oenological tannins can limit the appearance of LST in both model wine [3] and white wine [4]. This research aimed to evaluate the impact of certain oenological tannins, selected in a previous study as the most effective against LST [5], in both white and rosé wines.

Read More

IMPACT OF HARVEST DATE ON THE FINE MOLECULAR COMPOSITION OF MUST AND BORDEAUX RED WINE (VAR. MERLOT, CABERNET SAUVIGNON). FOCUS ON ACIDITY AND SENSORY IMPACT AFTER FIVE YEARS OF AGING

Climate change has brought several impacts that are becoming increasingly intense during the last few years and put at risk the quality of the berries or even the plant’s sustainability. Such extreme climatic events impact the composition of the wine while modulating its quality and the consumer preferences (Tempère et al., 2019). The three most important changes that take place in the must are: 1) decrease acidity, 2) increase of the concentration of sugar, hence increase of alcohol in the wine, and 3) modification
of the sensory balance and the development for example of cooked fruit aromas.

Read More

ACIDIC AND DEMALIC SACCHAROMYCES CEREVISIAE STRAINS FOR MANAGING PROBLEMS OF ACIDITY DURING THE ALCOHOLIC FERMENTATION

In a recent study several genes controlling the acidification properties of the wine yeast Saccharomyces cerevisiae have been identified by a QTL approach [1]. Many of these genes showed allelic variations that affect the metabolism of malic acid and the pH homeostasis during the alcoholic fermentation. Such alleles have been used for driving genetic selection of new S. cerevisiae starters that may conversely acidify or deacidify the wine by producing or consuming large amount of malic acid [2]. This particular feature drastically modulates the final pH of wine with difference of 0.5 units between the two groups.

Read More