GiESCO 2019 banner
IVES 9 IVES Conference Series 9 GiESCO 9 GiESCO 2019 9 Impact of crop load management on terpene content in gewürztraminer grapes

Impact of crop load management on terpene content in gewürztraminer grapes

Abstract

Context and purpose of the study ‐ Crop load management by cluster thinning can improve ripening and the concentration of key metabolites for grape and wine quality. However, little work has been done on testing the impact of crop load management on terpene content of white grapes. The goal of the study was to assess if by reducing crop load via cluster thinning growers can increase terpene concentration of grapes, as well as to test if the timing of thinning application affects terpene concentration.

Material and methods ‐ This study was performed in 2016, 2017, and 2018 in Oliver, British Columbia. Field‐grown Gewürztraminer vines were cluster‐thinned at two developmental stages, just after fruit‐set (Early Thinning) and at veraison (Late Thinning), in order to target three crop levels: Light Crop (7 tons/ha), Moderate Crop (10.5 tons/ha), and High Crop (14 tons/ha). Treatments were replicated on five plots arranged in a randomized block design. The effect of treatments on leaf gas exchanges, vine leaf area, and berry sugar (total soluble solid, TSS), acid (titratable acidity, TA), and terpene concentration was analyzed during ripening and at harvest. Free and glycosylated terpenes were identified and quantified using a SPME‐GC‐MS and a LI‐GC‐MS, respectively.

Results ‐ Crop level treatmentsdid not affect leaf gas exchanges and vine leaf area. TSS concentration during ripening and at harvest was higher in Light Crop and Moderate Crop treatments than in High Crop, particularly for Early Thinning treatments. High Crop and Light Crop‐Early Thinning determined the highest free terpene concentration at harvest; however, a significant interaction between treatment and year effects was observed. Total glycosylated terpenes at harvest were marginally affected by treatments (P = 0.063), and Light Crop‐Early Thinning determined the highest total glycosylated terpene concentration. Interestingly, total free terpenes were significantly affected by the treatments at the sampling before harvest (20‐21 Brix), when Light Crop‐Early Thinning determined a higher concentration of total free terpenes than High Crop. This result was consistently among the three years. Our study suggests that crop load management can be used as a tool to improve grape terpenes in scenarios (regions and/or seasons) where ripening is impaired and grapes cannot reach relatively high sugar levels. 

Download the PDF

DOI:

Publication date: June 19, 2020

Issue: GIESCO 2019

Type: Article

Authors

Yevgen KOVALENKO, Ricco TINDJAU, Simone Diego CASTELLARIN

Wine Research Centre, The University of British Columbia, 2205 East Mall, Vancouver, BC, V6T0C1,Canada

Contact the author

Keywords

Aroma, Grapevine, Ripening, Thinning, Yield

Tags

GiESCO 2019 | IVES Conference Series

Citation

Related articles…

The effect of ultrasounds in syrah wine quality is not dependent on the ripening or sanitary status of the grapes

Different studies have demonstrated that the application of ultrasounds (US) to crushed grapes improves chromatic characteristics of the wines (1,2), increases their polysaccharide content (3) and some aroma compounds are also favored (4,5)

Read More

Design of microbial consortia to improve the production of aromatic amino acid derived compounds during wine fermentation

Wine contains secondary metabolites derived from aromatic amino acids (AADC), which can determine quality, stability and bioactivity. Several yeast species, as well as some lactic acid bacteria (LAB), can contribute in the production of these aromatic compounds. Winemaking should be studied as a series of microbial interactions, that work as an interconnected network, and can determine the metabolic and analytical profiles of wine. The aim of this work was to select microorganisms (yeast and LAB) based on their potential to produce AADC compounds, such as tyrosol and hydroxytyrosol, and design a microbial consortium that could increase the production of these AADC compounds in wines.

Read More

Effect of power ultrasound treatment on free and glycosidically-bound volatile compounds and the sensorial profile of red wines

AIM Aiming to explore the possibility of shortening red winemaking maceration times (1,2), this study presents the effect of the application of high-power ultrasounds to crushed grapes, at winery-scale, on the content of varietal volatile compounds (free and glycosidically-bound) in musts and on the overall aroma of wines.

Read More

Comparison of fortified, sfursat and passito winemaking techniques for the enhancement of the oenological potential of the black grape cultivar Moscato nero d’Acqui (Vitis vinifera L.)

One of the key factors of the economical development of viticulture and wine industry in specific limited areas is the exploitation of ancient, local grape varieties. Therefore, in recent years the growing interest to rediscover minor varieties, previously cultivated, has promoted many studies. With this regard, the focus of this study was the Vitis vinifera L. cultivar Moscato nero d’Acqui, nowadays found only in old vineyards in the Acqui zone (North-West Italy). In particular, the aims of this work were: i) to investigate secondary metabolites profile of the grapes, and ii) to evaluate the attitude to the production of special wines.

Read More

Berry shrivel causes – summarizing current hypotheses

Diverse ripening disorders affect grapevine resulting in high economic losses worldwide. The common obvious symptom is shriveling berries, however the shriveling pattern and the consequences for berry quality traits are distinct in each disorder. Among them, the disorder berry shrivel is characterized by a reduced sugar accumulation short after the onset of berry ripening leaving the clusters unsuitable for wine processing. Although our knowledge on BS increased recently, potential internal or external triggers contributing to the induction of BS are yet to be explored.

Read More