Tracing the origin of Argentine Malbec wines by sensometrics.

The study of terroir, increasingly popular in scientific circles, remains a challenging field, particularly in terms of sensory analysis. This paper summarizes our own contribution to the field-an approach for tracing the typicity of wines by sensometrics, using the Malbec variety as a case study. This large-scale research fingerprinted 81 wines from 29 parcels from highly contrasting environments (varying climate, elevation, and soils), produced under standardized conditions in three consecutive vintages. Wines were evaluated through descriptive sensory analysis (DA) by a trained panel, and sensory descriptors were associated with different size geographic scales (zones, departments, and Geographic Indications (GIs)). The application of different sensometric tools allowed us to describe the typicity of wines and discriminate each region, proposing a novel methodology for the comprehensive evaluation of terroir from a sensory viewpoint. The vintage effect was very strong at the departmental and GI level, with aroma, taste and mouthfeel descriptors varying annually. However, certain origin descriptors remained consistent, providing insight into the typicity of Malbec. Considering the extension of the experimental study performed, this methodology provides a proof of concept for understanding both terroir and vintage effects from a sensorial perspective, offering wine producers and consumers a clear message backed by scientific evidence.

Three-year study of DNA cytosine methylation dynamics in transplanted Malbec grapevines.

DNA cytosine methylation, an epigenetic mechanism involved in gene regulation and genome stability, remains poorly understood in terms of its role under changing environmental conditions. Previous research using methylation-sensitive amplified polymorphism (MSAP) markers in a Vitis vinifera L. cv. Malbec clone showed vineyard-specific DNA methylation polymorphism, but no change in overall methylation levels. To complement these findings, the present study investigates the intra-seasonal epigenetic dynamics between genetically identical plants grown in different vineyards through a transplanting experiment. Cuttings of the same clone, showing differential methylation patterns imposed by the vineyard of origin (Agrelo and Gualtallary), were cultivated in a common vineyard (Lunlunta). Using high-performance liquid chromatography-ultraviolet detection, the quantification of global DNA 5-methylcytosine (5-mC) levels revealed relatively low overall 5-mC percentages in grapevines, with higher levels in Agrelo (5.8%) compared to Gualtallary plants (3.7%). The transplanted plants maintained the 5-mC levels differences between vineyards (9.8% vs 6.2%), which equalized in subsequent seasons (7.5% vs 7%). Additionally, the study examined 5-mC polymorphism using MSAP markers in Lunlunta transplanted plants over three seasons. The observed differences between vineyards in MSAP patterns during the initial growing season gradually diminished, suggesting a reprogramming of the hemimethylated pattern following implantation in the common vineyard. In contrast, the non-methylated pattern exhibited greater stability, indicating a potential memory effect. Overall, this study provides valuable insights into the dynamic nature of DNA methylation in grapevines under changing environmental conditions, with potential implications for crop management and breeding strategies.

Occurrence of Nine Grapevine Viruses in Commercial Vineyards of Mendoza, Argentina.

Grapevine is a widely grown fruit crop that is seriously affected by different viruses, reducing grape yield and quality, as well as threatening profitability. Vineyard disease management requires accurate identification of viral infections. This study aimed to survey the presence of ten grapevine viruses in four geographic sites in the Mendoza province of Argentina. Two hundred twenty-three composite cane samples from 1060 plants of six cultivars were collected from 26 blocks distributed across 11 vineyards. The cane samples were screened by RT-PCR for the following viruses: grapevine leafroll-associated viruses 1-4 (GLRaV 1, 2, 3, and 4), grapevine fanleaf virus (GFLV), grapevine fleck virus (GFkV), grapevine virus A (GVA) and B (GVB), grapevine rupestris stem pitting associated virus (GRSPaV), and arabis mosaic virus (ArMV). The results showed an uneven occurrence of viruses through the sampled regions, with GRSPaV being prevalent (71.1%), followed by GFLV (28.9%), GFkV (20.6%), and GLRaV-2 (14.7%). GVB was not detected. This study revealed a moderate prevalence of viruses associated with economically impactful diseases in the vineyards surveyed.

Terroir and vintage discrimination of Malbec wines based on phenolic composition across multiple sites in Mendoza, Argentina.

This study evaluated the phenolic profiles of Malbec wines made from grapes of 23 parcels distributed in 12 geographical indications (GIs) from Mendoza, Argentina. Wines were elaborated under standardized winemaking conditions over three consecutive vintages (2016-2018). Data discriminated wines from different GIs and parcels, based on an integrative data analysis by chemometric tools. Vintage effect and specific phenolic compounds were associated with some GIs or parcels. As well, regional climate conditions allowed partial discrimination of the GIs (and also some parcels). A random forest analysis correctly identified 11 out of 23 individual parcels across the different vintages. The most notorious compounds associated with such classification were p-coumaric acid, delphinidin-3-O-glucoside, caffeic acid, quercetin and peonidin-3-O-glucoside. The presented research allows to individualize, through phenolic profiles, parcels with unique characteristics over years. This is the first report characterizing Malbec wines coming from several GIs (and individual parcels) in different vintages. These results are strongly related to terroir features of wines, contributing to a better communication to consumers and to position Argentinean wines.

Aging of Malbec wines from Mendoza and California: Evolution of phenolic and elemental composition.

This work aimed to investigate the evolution of phenolic compounds and elements during the aging of Malbec red wines from different regions of Mendoza (Argentina) and California (United States). The profiles of low molecular weight polyphenols and anthocyanins were analyzed using high-performance liquid chromatography with a diode-array detector (HPLC-DAD), and the elemental composition using microwave plasma-Atomic emission spectrometry (MP-AES). Through uni- and multivariate statistical analyses, the effects of aging time and region on wine were investigated. It was observed that aging time was a significant factor that affected the phenolic compound profile in the studied Malbec wines studied and that after five years of aging, the wines could be differentiated according to region. The results of this study may impact decisions made regarding the storage of Malbec wines in the future.

Phenolic and sensory profiles discriminate geographical indications for Malbec wines from different regions of Mendoza, Argentina.

Malbec wines from 27 parcels from the three most important winemaking regions of Mendoza, Argentina, were produced under standardized winemaking conditions, and analyzed for phenolic composition and by means of sensory descriptive analysis. Different methods of characterization and cluster analysis for each data matrix showed that some locations of Mendoza could be significantly separated from each other. The results of unsupervised statistical methods were compared using a test for similarities and divergences, also showing that different locations may be associated. The current report is the first one characterizing Malbec wines from the three major producing regions of Argentina using two different ways for locations classification. The effects of climate and geographical origin of Malbec grapes on the quality parameters of resulting wines were also evidenced. These results have enological and viticulture interest for the winemaking industry as the vineyard site selection for Malbec can considerably affect quality attributes.

Regional sensory and chemical characteristics of Malbec wines from Mendoza and California.

Malbec grapes are widely grown and studied in Argentina, whereas the smaller production in California is less well known. This study sought to define and compare Malbec wine compositions from various regions in Mendoza, Argentina and California, USA. The Malbec wines were clearly separated, based on their chemical and sensory profiles, by wine region and country. Descriptors of Malbec wines were aromas of cooked vegetal, earthy, soy and volatile acidity, as well as acidic taste and astringent mouthfeel, regardless of the region of origin. Malbec wines from Mendoza generally had more ripe fruit, sweetness, and higher alcohol levels, while the Californian Malbec wines had more artificial fruit and citrus aromas, and bitter taste. Compositional differences between the two countries were related more to altitude than precipitation and growing degree days. To our knowledge, this is the first time that an extensive regionality study has been attempted for Malbec wines.