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…

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.

An analytical framework to site-specifically study climate influence on grapevine involving the functional and Bayesian exploration of farm data time series synchronized using an eGDD thermal index

Climate influence on grapevine physiology is prevalent and this influence is only expected to increase with climate change. Although governed by a general determinism, climate influence on grapevine physiology may present variations according to the terroir. In addition, these site-specific differences are likely to be enhanced when climate influence is studied using farm data. Indeed, farm data integrate additional sources of variation such as a varying representativity of the conditions actually experienced in the field. Nevertheless, there is a real challenge in valuing farm data to enable grape growers to understand their own terroir and consequently adapt their practices to the local conditions. In such a context, this article proposes a framework to site-specifically study climate influence on grapevine physiology using farm data. It focuses on improving the analysis of time series of weather data. The analytical framework includes the synchronization of time series using site-specific thermal indices computed with an original method called Extended Growing Degree Days (eGDD). Synchronized time series are then analyzed using a Bayesian functional Linear regression with Sparse Steps functions (BLiSS) in order to detect site-specific periods of strong climate influence on yield development. The article focuses on temperature and rain influence on grape yield development as a case study. It uses data from three commercial vineyards respectively situated in the Bordeaux region (France), California (USA) and Israel. For all vineyards, common periods of climate influence on yield development were found. They corresponded to already known periods, for example around veraison of the year before harvest. However, the periods differed in their precise timing (e.g. before, around or after veraison), duration and correlation direction with yield. Other periods were found for only one or two vineyards and/or were not referred to in literature, for example during the winter before harvest.

Local ancient grapevine cultivars to face future viticulture

Among the different strategies to cope with the negative impacts of climate change on viticulture, the exploitation of genetic diversity is one of the most promising to adapt to new conditions and maintain wine production and quality. One of the biggest concerns in the context of climate change is to improve water use efficiency (WUE). In this way, the use of genotypes that present a better response to drought and high WUE is a key issue. In this work, physiological performance analysis was conducted to compare the water deficit stress (WDS) responses of local and widespread grapevines cultivars. Leaf gas exchange, water use efficiency (WUE) at different levels (leaf and long-term WUE (∆13C)), leaf osmotic adjustment and other water relations parameters were determined in plants under well-watered and WDS conditions alongside assessment of the levels of foliar hormones concentrations. Results denote that local cultivars displayed better physiological performance under WDS as compared to the widely-distributed ones. he results corroborate the hypothesis that better stomatal control allows increasing leaf WUE under drought as occurred in the local Callet cv.; but the minority local cultivar Escursac cv. showed high WUE under both treatments. In this case, high WUE can be related to maintaining higher photosynthetic activity under drought. The different mechanisms underlying the better performance under WDS and high WUE of minority local cultivars are discussed.

Effect of the commercial inoculum of arbuscular mycorrhiza in the establishment of a commercial vineyard of the cultivar “Manto negro

The favorable effect of symbiosis with arbuscular mycorrhizal fungi (AMF) has been known and studied since the 60s. Nowadays, many companies took the chance to start promoting and selling commercial inoculants of AMF, in order to be used as biofertilizers and encourage sustainable biological agriculture. However, the positive effect of these commercial biofertilizers on plant growth is not always demonstrated, especially under field conditions. In this study, we used a commercial inoculum on newly planted grapevines of a local cultivar grafted on a common rootstock R110. We followed the physiological status of vines, growth and productivity and functional biodiversity of soil bacteria during the first and second years of 20 inoculated with commercial inoculum bases on Rhizophagus irregularis and Funeliformis mosseaeAMF at field planting time and 20 non-inoculated control plants. All the parameters measured showed a neutral to negative effect on plant growth and production. The inoculated plants always presented lower values of photosynthesis, growth and grape production, although in some cases the differences did not reach statistical significance. On the contrary, the inoculation supposed an increase of the bacterial functional diversity, although the differences were not statistically significant either. Several studies show that the effect of inoculation with AMF is context-dependent. The non-favorable effects are probably due to inoculation ineffectiveness under complex field conditions and/or that, under certain conditions, AMF presence may be a parasitic association. This puts into question the effectiveness of its application in the field. Therefore, it is recommended to only resort to this type of biofertilizer when the cultivation conditions require it (e.g., very low previous microbial diversity, foreseeable stress due to drought, salinity, or lack of nutrients) and not as a general fertilization practice.

Climate change projections to support the transition to climate-smart viticulture

The Earth’s system is undergoing major changes through a wide range of spatial and temporal scales as a response to growing anthropogenic radiative forcing, which is pushing the whole system far beyond its natural variability. Sources of greenhouse gases largely exceed their sinks, thus leading to a strengthened greenhouse effect. More energy is thereby being supplied to the system, with inevitable shifts in climatic patterns and weather regimes. Over the last decades, these modifications have been manifested in the full statistical distributions of the atmospheric variables, with dramatic changes in the frequency and intensity of extremes. Natural hazards, such as severe droughts, floods, forest fires, or heatwaves, are being triggered by extreme atmospheric events worldwide, thus threatening human activities. Viticultculture is not only exposed to changing climates but is also highly vulnerable, as grapevine phenology and physiological development are strongly controlled by atmospheric conditions. Therefore, the assessment of climate change projections for a given region is critical for climate change adaptation and risk reduction in viticulture. By adopting timely and suitable measures, the future sustainability and resiliency of the sector can be fostered. Climate-grapevine chain modelling is an essential tool for better planning and management. However, the accuracy of the resulting projections is limited by many uncertainties that must be duly taken into account when transferring knowledge to stakeholders and decision-makers. Climate-smart viticulture will comprise ensembles of locally tuned strategies, envisioning both adaptation and mitigation, assisted by emerging technologies and decision-support systems.