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…

Elevational range shifts of mountain vineyards: Recent dynamics in response to a warming climate

Increasing temperatures worldwide are expected to cause a change in spatial distribution of plant species along elevational gradients and there are already observable shifts to higher elevations as a consequence of climate change for many species. Not only naturally growing plants, but also agricultural cultivations are subject to the effects of climate change, as the type of cultivation and the economic viability depends largely on the prevailing climatic conditions. A shift to higher elevations therefore represents a viable adaptation strategy to climate change, as higher elevations are characterized by lower temperatures. This is especially important in the case of viticulture because a certain wine-style can only be achieved under very specific climatic conditions. Although there are several studies investigating climatic suitability within winegrowing regions or longitudinal shifts of winegrowing areas, little is known about how fast vineyards move to higher elevations, which may represent a viable strategy for winegrowers to maintain growing conditions and thus wine-style, despite the effects of climate change. We therefore investigated the change in the spatial distribution of vineyards along an elevational gradient over the past 20 years in the mountainous wine-growing region of Alto Adige (Italy). A dataset containing information about location and planting year of more than 26000 vineyard parcels and 30 varieties was used to perform this analysis. Preliminary results suggest that there has been a shift to higher elevations for vineyards in general (from formerly 700m to currently 850 m a.s.l., with extreme sites reaching 1200 m a.s.l.), but also that this development has not been uniform across different varieties and products (i.e. vitis vinifera vs hybrid varieties and still vssparkling wines). This is important for climate change adaptation as well as for rural development. Mountain areas, especially at mid to high elevations, are often characterized by severe land abandonment which can be avoided to some degree if economically viable and sustainable land management strategies are available.

Rootstock regulation of scion phenotypes: the relationship between rootstock parentage and petiole mineral concentration

Grapevine is grown as a graft since the end of the 19th century. Rootstocks not only provide tolerance to Phylloxera but also ensure the supply of water and mineral nutrients to the scion. Rootstocks are an important mean of adaptation to environmental conditions, because the scion controls the typical features of the grapes and wine. However, among the large diversity of rootstocks worldwide, few of them are commercially used in the vineyard. The aim of this study was to investigate the extent to which rootstocks modify the mineral composition of the petioles of the scion. Vitis vinifera cvs. Cabernet-Sauvignon, Pinot noir, Syrah and Ugni blanc were grafted onto 55 different rootstock genotypes and planted in a vineyard as three replicates of 5 vines. Petioles were collected in the cluster zone with 6 replicates per combination. Petiolar concentrations of 13 mineral elements (N, P, K, S, Mg, Ca, Na, B, Zn, Mn, Fe, Cu, Al) at veraison were determined. Scion, rootstock and the interaction explained the same proportion of the phenotypic variance for most mineral elements. Rootstock genotype showed a significant influence on the petiole mineral element composition. Rootstock effect explained from 7 % for Cu to 25 % for S of the variance. The difference of rootstock conferred mineral status is discussed in relation to vigor and fertility. Rootstocks were also genotyped with 23 microsatellite markers. Data were analysed according to genetic groups in order to determine whether the petiole mineral composition could be related to the genetic parentage of the rootstock. Thanks to a highly powerful design, it is the first time that such a large panel of rootstocks grafted with 4 scions has been studied. These results give the opportunity to better characterize the rootstocks and to enlarge the diversity used in the vineyard.

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.

Influence of weather and climatic conditions on the viticultural production in Croatia

The research includes an analysis of the impact of weather conditions on phenological development of the vine and grape quality, through monitoring of four experimental cultivars (Chardonnay, Graševina, Merlot and Plavac mali) over two production years. In each experimental vineyard, which were evenly distributed throughout the regions of Slavonia and The Croatian Danube, Croatian Uplands,

Diagnosis of soil quality and evaluation of the impact of viticultural practices on soil biodiversity in a vineyard in southwestern France

Viticulture is facing two major changes – climate change and agroecological transition. In both cases, soil quality is seen as a lever to move towards a more sustainable viticulture. However, soil biological quality is little considered in the implementation of viticultural practices. Gascogn’Innov (2017-2022) is an Operational Group funded by the European Innovation Partnership for Agriculture. As such, it brings together winegrowers from the south-west of France, scientists, advisors and technicians, around a project focused on viticultural soil biological functioning and the design of technical routes more respectful toward soil heritage. To achieve this, the project aims to acquire references on the impact of viticultural practices on soil biology from a dynamic way, and to test a methodology to integrate information provided by the soil bioindicators to manage farming systems. A set of indicators of soil biological quality are evaluated in the project: microorganisms (bacteria and fungi abundance and diversity), fauna (abundance and diversity of nematodes and earthworms), physico-chemical characteristics, soil structure assessment and degradation rate of organic matter. Based on a network of 13 plots that have been subject to an initial diagnosis in 2017, several agronomical practices to restore soil fertility are experimented to redesign the cropping system (for instance plant cover, organic matter inputs, reduction of herbicides, mineral fertilizers). System redesign was made in collaboration by winegrowers and an interdisciplinary group of experts (agronomists, biologists). Several indicators are measured on vine and soil at each vintage to assess vine health and productivity. At the end of the project (2021), a final diagnosis was carried out. Gascogn’Innov allowed to create a regional database on the quality of wine-growing soils, which permitted to evaluate the effect of practices according to soil types. Especially, decreasing the intensity of tillage and increasing the duration and diversity of grass coverage tends to increase the abundance of all the organisms studied. This project confirmed the value of soil biological quality indicators to drive the sustainability of practices, but also highlighted the key-role of expertise, in both agronomy and soil biology, to help winegrowers understand and appropriate their soil quality diagnoses.