IVAS 2022 banner
IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 Determination of Aroma Compounds in Grape Mash under Conditions of Tasting by On-line Near-Infrared Spectroscopy

Determination of Aroma Compounds in Grape Mash under Conditions of Tasting by On-line Near-Infrared Spectroscopy

Abstract

The production of high-quality wines requires the use of high-quality grapes. Some compounds originating from grapes may negatively influence the odour and flavour of the resulting wine in their original form or as precursors for off-odours and –flavours. Therefore, a rapid evaluation of the grapes directly upon receival at the winery is advantageous. Up to now, grape aroma is mainly evaluated by tasting, however, this leads to subjective results. The use of near-infrared (NIR) spectroscopy allows a rapid, objective and destruction-free analysis without previous sample preparation. Moreover, the measurement can be integrated into an existing process without additional sampling.

The aroma compounds in grape mash samples were analysed by gas chromatography-mass spectrometry (GC-MS) under highly comparable conditions to those in the mouth (temperature, pH value, enzymes etc.). This way, only compounds were detected, which are released during tasting. Furthermore, the destruction of compounds and possible artefact formation should be avoided. The determined concentrations of the detected aroma compounds were related to the corresponding NIR spectra of the samples and calibration models were developed for determination by NIR spectroscopy.

Regarding the presence and the concentrations of the detected aroma compounds, differences occurred between samples with varying phytosanitary status of the grapes and for several grape varieties. The addition of artificial saliva solution before measurement did not significantly influence the concentrations of the aroma compounds. Global calibration models for the single aroma compounds showed varying results (0,365 ≤ R2 ≤ 0,976). Separate calibration models for cultivation region and/or grape colour improved the prediction accuracy.

For the majority of the detected aroma compounds at least a semi-quantitative determination by NIR spectroscopy is possible to evaluate the aroma quality of grapes. However, more samples need to be analysed to extend the models and to assure sufficient prediction accuracy.

DOI:

Publication date: June 27, 2022

Issue: IVAS 2022

Type: Poster

Authors

Gehlken Jana1, Pour Nikfardjam Martin2 and Zörb Christian1

1University of Hohenheim, Institute of Crop Science, Dept. Quality of Plant Products and Viticulture (340e)
2State Research Institute for Viticulture and Pomiculture, Traubenplatz 5, 74189 Weinsberg/Germany

Contact the author

Keywords

Near-infrared spectroscopy, grape tasting, grape mash, aroma compounds, calibration

Tags

IVAS 2022 | IVES Conference Series

Citation

Related articles…

Correlative study between degradation of rosé wine under accelerated conditions and under normal conditions

Several studies have tried to develop different methods to study the photodegradation of wine in an accelerated way, trying to elucidate the effect of light on the wine compounds[1]. In a previous study, our team developed a chamber that speeds up the photodegradation of rosé wine[2]. In the present work we have tried to establish a correlation between irradiation times in accelerated conditions and the natural exposure to the cycles of light that usually exist in markets or at home.

Hydroxycinnamic acids in grapes and wines made of Tannat, Marselan and Syrah from Uruguay

Background: hydroxycinnamic acids (HCA), present in pulp and skin of grapes, are relevant compounds in red winemaking

Phenolic composition of Xinomavro (vitis vinifera L.cv.) grapes from different regions of Greece

[lwp_divi_breadcrumbs home_text="IVES" use_before_icon="on" before_icon="||divi||400" module_id="publication-ariane" _builder_version="4.20.4" _module_preset="default" module_text_align="center" module_font_size="16px" text_orientation="center"...

Time vs drought: leaf age rather than drought drives osmotic adjustment in V. vinifera cv. Pinot Noir

Global warming and increased frequency and/or severity of drought events are among the most threatening consequences of climate change for agricultural crops. In response to drought, grapevine (as many other plants) exhibits osmotic adjustment through active accumulation of osmolytes which in turn shift the leaf turgor loss point (TLP) to more negative values, allowing to maintain stomata opened at lower water potentials1. We investigated the capacity of Pinot noir leaves to modulate their osmotic potential as a function of: (i) time (seasonal osmoregulation), (ii) growing temperatures, and (iii) drought events, to enhance comprehension of the resilience of grapevines in drought conditions. We performed trails under semi-controlled field conditions, and in two different greenhouse chambers (20/15 °C vs 25/20 °C day/night). For two consecutive vegetative seasons, grafted potted grapevines (Pinot noir/SO4) were subjected to two different water regimes for at least 30 days: well-watered (WW) and water deficit (WD).

Organic volatile compounds as suitable markers of grapevine response to defense elicitors in the vineyard

In greenhouse, emission of volatile organic compounds (VOC) by grapevine leaves has already been reported in response to the defence elicitor sulfated laminarin (PS3) [1]. In order to check that this response was not specific to PS3, experiments were conducted on Vitis cv Marselan plantlets with several other elicitors of different chemical structures: i.e. Bastid® (COS-OGA),