Terroir 2020 banner
IVES 9 IVES Conference Series 9 Distinguishing of red wines from Northwest China by colour-flavour related physico-chemical indexes

Distinguishing of red wines from Northwest China by colour-flavour related physico-chemical indexes

Abstract

Aim: Northwest China occupies an important position in China’s wine regions due to its superior geographical conditions with dry climate and sufficient sunlight. In this work, we aimed to investigate the physico-chemical colour and flavour characteristics of red wine in Northwest China.

Methods and Results: A total of 196 commercial dry red wines from Ningxia autonomous region, Gansu province and Xinjiang autonomous region in Northwest China were sampled. Spectro-analysis and chemical titration were used to quantify physico-chemical indicators related to wine colour and flavour, including total anthocyanins, co-pigments, monomeric anthocyanins, polymeric anthocyanins, ionisation index, CIE color space, total phenols, flavonol, ethanol index, total tannin, gelatin index, HCl index, DPPH antioxidant activity, tartrate ester, titratable acid, and pH value. Principal Component Analysis (PCA) of the data showed that wine samples in Ningxia, Gansu and Xinjiang region had obvious clustering phenomena. Among them, total anthocyanin and polymeric anthocyanins in Ningxia wines were higher compared to other wines. Ningxia wines also had the highest total acids and lighter colour whereas Gansu wines had greater amounts of monomeric anthocyanins, co-pigments and phenolic indexes. Gansu wines were darker in colour with the highest pH values. The parameters of Xinjiang wines were ranged between Ningxia wines and Gansu wines. PCA also showed good discriminant results on wine vintages. Wines older than 3 years had more polymeric anthocyanins and stable colour whilst younger wines had more total anthocyanin and monomeric anthocyanin with brighter colour. In addition, younger wines had the highest phenolics. Grape cultivars also contributed to the difference of colour and flavour associated indexes. Among them, Cabernet Sauvignon wines displayed distinct characteristics compared to other wines. Values of total anthocyanins, DPPH antioxidant activity, ionisation index, Cab and HCl acid indexes of Cabernet Sauvignon wines were higher than those of other wines. Finally, a convolutional neuralnetwork model was used to discriminate and analyses the categorical data of wines. These data were standardized and analysised using TensorFlow. The corresponding fitness indexes were 99.14%, 90.52%, and 89.66% from Northwest China based on region, cultivar, and vintage.

Conclusions: 

Colour and flavour associated indexes of wines from Northwest China are strongly impacted by wine regions, cultivars, and vintages.

Significance and Impact of the Study: Wine regions in Northwest China are developing drastically in recent decades, however relevant criteria of colour-flavour quality to help manipulate winemaking practices are lacking in local wineries to ensure the quality of wine style. Our results highlighted the possibility of establishing such wine quality criteria specially for Northwest China based on building a discrimination model on wine physico-chemical related indicators.

DOI:

Publication date: March 17, 2021

Issue: Terroir 2020

Type: Video

Authors

Yu Zhao1, Guojie Jin1, Jiao Jiang1, Shijin Xue1, Kai Hu1*, Yongsheng Tao1,2*

College of Enology, Northwest A&F University, Yangling, Shaanxi 712100, China
Shaanxi Engineering Research Center for Viti-viniculture, Yangling, Shaanxi 712100, China

Contact the author

Keywords

Wine region, spectro-analysis, discrimination analysis, neural network analysis, colour-flavour physico-chemical indicators

Tags

IVES Conference Series | Terroir 2020

Citation

Related articles…

Climate change impacts: a multi-stress issue

With the aim of producing premium wines, it is admitted that moderate environmental stresses may contribute to the accumulation of compounds of interest in grapes. However the ongoing climate change, with the appearance of more limiting conditions of production is a major concern for the wine industry economic. Will it be possible to maintain the vineyards in place, to preserve the current grape varieties and how should we anticipate the adaptation measures to ensure the sustainability of vineyards? In this context, the question of the responses and adaptation of grapevine to abiotic stresses becomes a major scientific issue to tackle. An abiotic stress can be defined as the effect of a specific factor of the physico-chemical environment of the plants (temperature, availability of water and minerals, light, etc.) which reduces growth, and for a crop such as the vine, the yield, the composition of the fruits and the sustainability of the plants. Water stress is in many minds, but a systemic vision is essential for at least two reasons. The first reason is that in natural environments, a single factor is rarely limiting, and plants have to deal with a combination of constraints, as for example heat and drought, both in time and at a given time. The second reason is that plants, including grapevine, have central mechanisms of stress responses, as redox regulatory pathways, that play an important role in adaptation and survival. Here we will review the most recent studies dealing with this issue to provide a better understanding of the grapevine responses to a combination of environmental constraints and of the underlying regulatory pathways, which may be very helpful to design more adapted solutions to cope with climate change.

Postveraison shoot trimming in Tannat and Merlot: preliminary results on yield components, plant balance and berry composition

There is currently a trend towards the production of wines with low alcohol content. To achieve this, grapes with low sugar content must be used. There are techniques at the vineyard level that can delay ripening and avoid excessive sugar accumulation without, a priori, affecting the final polyphenol content. Postveraison shoot trimming (PVST) is experimentally evaluated for these purposes, but its impact under Uruguayan climatic conditions with high interannual variability is not known. The aim of this work is to assess the PVST in Tannat and Merlot cultivars and their impact on yield components, plant balance and berry primary composition. In this study, two commercial vineyards of 10 years old Tannat and Merlot (grafted on SO4) at Canelones Department were selected. During the 2020-201 growing season, grapevines were submitted to PVST when grapes reached 15º Brix. In a randomized block, trimmed (T) and control (C) plants were evaluated with three repetitions each cultivar. Evaluation of the evolution of primary berry composition during ripening, measurement of yield components and plant balance were performed. For both cultivars, PVST did not affect yield components. Merlot reached 5.4 kg per plant and Tannat 7.1 kg, with not statistical significance between treatments. However, statistical differences were observed in terms of plant balance. In Merlot Ravaz Index reached a difference of 5.3 (12.0 in T and 6.7 in C) meanwhile Tannat reached 3.5 of statistical difference (13.7 in T and 10.2 in C). The tendency to imbalance for the treated plants had an impact on the final grape composition. Merlot grapes showed statistical difference in final total acidity (0.3 g of difference between treatments) while treatments impact final sugar content on Tannat grapes (10.0 g of difference between treatments). Further studies are needed to assess the impact of different canopy management techniques in our conditions.

Short-term relationships between climate and grapevine trunk diseases in southern French vineyards

[lwp_divi_breadcrumbs home_text="IVES" use_before_icon="on" before_icon="||divi||400" module_id="publication-ariane" _builder_version="4.19.4" _module_preset="default" module_text_align="center" module_font_size="16px" text_orientation="center"...

A predictive model of spatial Eca variability in the vineyard to support the monitoring of plant status

[lwp_divi_breadcrumbs home_text="IVES" use_before_icon="on" before_icon="||divi||400" module_id="publication-ariane" _builder_version="4.19.4" _module_preset="default" module_text_align="center" module_font_size="16px" text_orientation="center"...

austrianvineyards.com: online viewer of all designations of Austrian wine

To digitally record and present all the origins of Austrian wines in the same perfect and clear way was the motivation for the Austrian Wine Marketing Board (Austrian Wine) to start with the project in 2018. In June 2021 the results were presented to the public in an online viewer showing all the designations of Austrian wine, available at https://austrianvineyards.com in a largely barrier-free manner. The online viewer provides tailored individual maps fitted to the respective zoom level. The smallest unit of wine-origins in Austria is called Ried and is displayed in a plot-specific manner highlighting areas under vine. Information on the Ried include administrative district, winegrowing municipality, cadastral municipality, large collective vineyard site, specific winegrowing region, generic winegrowing region, winegrowing area and, in many cases, an illustrative picture. Complementary data on the size, elevation (minimum-maximum), orientation (in 8 sectors plus flat) and gradient (minimum, maximum, average) are based on the area under vine according to the EU’s Integrated Administration and Control System. Additional information covers climate data. The diagrams are taken from the monthly breakdown of data in the annals of the Central Institute for Meteorology and Geodynamics, Austria provide a display of values for air temperature, precipitation, and sunshine hours for the reference year and the long-term average. Seasonal aggregated data on temperature, precipitation, and sunshine hours complete the display. Short descriptions with emphasis on geology and soil, field name in historical maps, etymology of the denomination, and main planted variety complements the available information for the main designations in the online viewer. These descriptions are compiled by winegrowers, geologists, historians, and journalists. All the information and data can be extracted to a pdf-file. Printed vineyard maps are also available. Missing content regarding wine origins in Styria will be completed in winter 2021/22.