Macrowine 2021
IVES 9 IVES Conference Series 9 Assay of distinct modes of polysaccharidases dosage in vinification with cv. Malbec. Effects on microbiological evolution, color and skin depletion

Assay of distinct modes of polysaccharidases dosage in vinification with cv. Malbec. Effects on microbiological evolution, color and skin depletion

Abstract

In the maceration stage of winemaking, enzymes can be used to degrade the polysaccharides present in the cell walls and middle sheets, and thus facilitate the extraction of juice and the release of polyphenols and aroma precursors retained in the grape skins. This work aims to analyze the influence of two enzyme complexes produced by autochthonous yeasts on the red winemaking process, in order to evaluate their effect on the chemical composition of the wines obtained, as well as on the extraction of color and polyphenols, and the depletion of the skin. Two strains previously selected for the effect of their enzymatic complex on the color extraction and improvement in the technological properties of the grape must were used (Longhi et al., 2019). A multi-enzymatic extract from Aureobasidium pullulans m11-2 was obtained by inoculating the microorganism in a broth according to Moyo et al. (2003) with modifications (pH 3.8) and incubated with stirring at 28°C for 72 h. Pectinase, xylanase, cellulase and amylase activities were quantified by determining reducing sugars by DNS, modified by Qian Li et al. (2015). Likewise, Torulaspora delbrueckii m7-2 was used for the production of the enzyme complex during vinification. Malbec red grapes (Vitis vinifera L.) from San Rafael (Mendoza) wine region, vintage 2021, were used to conduct the vinifications. The must obtained by crushing 60 Kg of grapes was corrected in acidity, sulfited (50 ppm) and distributed in 5 L containers. Four winemaking assays were performed, in duplicate: (1) inoculation with a native strain of Sacchromyces cerevisiae (SR1), at 108 cell/mL as inoculum, conducted at 20°C (control, C); (2) sequential inoculation of T. delbrueckii m7-2, with an initial cellular concentration of 107 cells/mL, followed by SR1 inoculation at 4th day (Td); (3) cold pre-fermentation maceration (CPM, 8°C-4 days) with m11-2 enzyme extract and SR1 inoculation (Ap); and (4) CPM without enzymatic treatment and SR1 inoculation (E). Growth kinetics of total yeasts were determined on YPD and DRBC agar, and of non-Saccharomyces yeasts in lysine medium. All enzymatic activities were monitored at pH 3.80 and 20°C. The pectinolytic activity was the main one, showing a level of 1.80 U/mL in the m11-2 extract and an initial level of 1.47 U/mL for the in situ producer strain (m7-2). Microscopic observations of the extracted skins in Ap and E vinifications were carried out to evaluate the effect of the enzymatic complex m11-2 on the cell wall, and were also compared with the fresh grape skins. Differences were observed between the skins enzymatically treated (Ap) and the control (E); the former showed cell emptying, greater rupture of the epidermis layers and less firmness, unlike the control that exhibited almost intact epidermal layers. These images allowed us to know the cell morphology of the varietal cv. Malbec and the enzymatic hydrolysis of its cell walls.

DOI:

Publication date: September 10, 2021

Issue: Macrowine 2021

Type: Article

Authors

Sara Jaquelina Longhi 

 Biotechnology Laboratory, Department of Biology and Food, Faculty of Sciences Applied to Industry, National University of Cuyo. Bernardo de Irigoyen 375, San Rafael, Mendoza, Argentina. National Council for Scientific and Technical Research (CONICET), Godoy Cruz 2290, Autonomous City of Buenos Aires, Argentina. ,María Carolina MARTÍN (1,2)  María Belén AVENDAÑO(1) María Gabriela MERÍN (1,2)   Luciana Paola PRENDES (1,2) Juliana GARAU (1,2) Vilma Inés MORATA DE AMBROSINI (1,2) (1) Biotechnology Laboratory, Department of Biology and Food, Faculty of Sciences Applied to Industry, National University of Cuyo. Bernardo de Irigoyen 375, San Rafael, Mendoza, Argentina. (2) National Council for Scientific and Technical Research (CONICET), Godoy Cruz 2290, Autonomous City of Buenos Aires, Argentina

Contact the author

Keywords

polysaccharidases, winemaking, polyphenols, malbec, grape cell wall

Citation

Related articles…

Co-design and evaluation of spatially explicit strategies of adaptation to climate change in a Mediterranean watershed

Climate change challenges differently wine growing systems, depending on their biophysical, sociological and economic features. Therefore, there is a need to locally design and evaluate adaptation strategies combining several technical options, and considering the local opportunities and constraints (e.g. water access, wine typicity). The case study took place in a typical and heterogeneous Mediterranean vineyard of 1,500 ha in the South of France. We developed a participatory modeling approach to (1) conceptualize local climate change issues and design spatially explicit adaptation strategies with stakeholders, (2) numerically evaluate their effects on phenology, yield and irrigation needs under the high-emissions climate change scenario RCP 8.5, and (3) collectively discuss simulation results. We organized five sets of workshops, with in-between modeling phases. A process-based model was developed that allowed to evaluate the effects of six technical options (late varieties, irrigation, water saving by reducing canopy size, adjusting cover cropping, reducing density, and shading) with various distributions in the watershed, as well as vineyard relocation. Overall, we co-designed three adaptation strategies. Delay harvest strategy with late varieties showed little effects on decreasing air temperature during ripening. Water constraint limitation strategy would compensate for production losses if disruptive adaptations (e.g. reduced density) were adopted, and more land got access to irrigation. Relocation strategy would foster high premium wine production in the constrained mountainous areas where grapevine is less impacted by climate change. This research shows that a spatial distribution of technical changes gives room for adaptation to climate change, and that the collaboration with local stakeholders is a key to the identification of relevant adaptation. Further research should explore the potential of adaptation strategies based on soil quality improvement and on water stress tolerant varieties.

Influence of a spontaneous cover crop on the vineyard and soil erosion under Mediterranean climate

Sixty five % of the agricultural area of the Basque Country located in the DO Ca Rioja corresponds to vineyards. More than 40% of it has an average slope greater than 10%, which makes it sensitive to erosive processes. Furthermore, it is foreseeable that extreme weather events (storms, hail, extreme heat and cold, etc.) will be favored due to climate change. Cover cropping can mitigate this risk, and therefore the objective of this work is to evaluate the impact that a vegetable cover has on the agronomic behavior of the vineyard, the quality of the grape and soil erosion. For this, a trial has been carried out with a Graciano variety vineyard with a slope between 10% -20% during the years 2020 and 2021. Conventional tillage management in the area has been compared (4-6 passes per year of tillage machinery) versus spontaneous vegetation cover management in the vineyard. This implies not tilling and allowing the grass of the land to colonize the range between the lines of vines, controlling their height through 1-3 mowing passes per year, always trying to affect the surface of the land as little as possible. The vegetative growth, yield and quality of the grape and wine was measured. Furthermore, erosion has been measured using Gerlasch boxes. The yield was lower in the second year of the trial in the cover crop treatment, but erosion was significantly reduced.

Leaf vine content in nutrients and trace elements in La Mancha (Spain) soils: influence of the rootstock

The use of rootstock of American origin has been the classic method of fighting against Phylloxera for more than 100 years. For this reason, it is interesting to establish if different rootstock modifies nutrient composition as well as trace elements content that could be important for determining the traceability of the vine products. A survey of four classic rootstocks (110-Richter, SO4, FERCAL and 1103-Paulsen) and four new ones (M1, M2, M3 and M4) provided by Agromillora Iberia. S.L.U., all of them grafted with the Tempranillo variety, has been carried out during 2019. The eight rootstocks were planted in pots of 500 cc, on three soils with very different characteristics from Castilla-La Mancha (Spain). In the month of July, the leaves were collected and dried in a forced air oven for seven days at 40ºC. Then, the samples were prepared for the analysis determination, carried out by X-Ray fluorescence spectrometry. The results obtained showed that in the case of content in mineral elements in leaf, separated by soil type, we can report the importance of few elements such as Si, Fe, Pb and, especially, Sr. The rootstock does not influence the composition of the vine leaf for the studied elements that are the most important in determining the geochemical footprint of the soil. The influence of the soil can be discriminated according to some elements such as Fe, Pb, Si and, especially, Sr.

Spatial determination of areas in the Western Balkans region favorable for organic production

In problematic conditions for production of grapes and wine caused by the COVID-19 pandemic and the resulting occurrence of wine surpluses, producers are increasingly turning to the innovative viticulture and winemaking of products that are more appealing to the market and the consumers. On the other hand, consumption of the food safety or organic products, and therefore of organic grapes and wine, is increasingly common in the world, in particular in Europe. The Regional Rural Development Standing Working Group (SWG RRD), as a regional intergovernmental organization gathers actors in the viticulture and winemaking sector from states and territories of the Western Balkans (South-East Europe) in the Expert Working Group for Wine, with the aim of improving viticulture and winemaking in this region through joint activities. In accordance with the aforementioned, the SWG RRD is working on advancing organic production of grapes and wine, and on recognition of specificities of the terroir of wine-growing areas in Western Balkans. In addition, as part of the project “Facilitation of Exchange and Advice on Wine Regulations in Western Balkan Countries” helmed by the German Federal Ministry of Food and Agriculture, in addition to harmonization of relevant legislation with EU regulations, efforts are being invested towards recognition of organic wines. Within activities and project implemented by this organization, expert analyses and scientific research of the terroir of Western Balkans were carried out, and some of the results are presented in this paper.

Climate ethnography and wine environmental futures

Globalisation and climate change have radically transformed world wine production upsetting the established order of wine ecologies. Ecological risks and the future of traditional agricultural systems are widely debated in anthropology, but very little is understood of the particular challenges posed by climate change to viticulture which is seen by many as the canary in the coalmine of global agriculture. Moreover, wine as a globalised embedded commodity provides a particularly telling example for the study of climate change having already attracted early scientific attention. Studies of climate change in viticulture have focused primarily on the production of systematic models of adaptation and vulnerability, while the human and cultural factors, which are key to adaptation and sustainable futures, are largely missing. Climate experts have been unanimous in recognising the urgent need for a better understanding of the complex dynamics that shape how climate change is experienced and responded to by human systems. Yet this call has not yet been addressed. Climate ethnography, coined by the anthropologist Susan Crate (2011), aims to bridge this growing disjuncture between climate science and everyday life through the exploration of the social meaning of climate change. It seeks to investigate the confrontation of its social salience in different locations and under different environmental guises (Goodman 2018: 340). By understanding how wine producers make sense of the world (and the environment) and act in it, it proposes to focus on the co-production of interdisciplinary knowledge by identifying and foreshadowing problems (Goodman 2018: 342; Goodman & Marshall 2018). It seeks to offer an original, transformative and contrasted perspective to climate change scenarios by investigating human agency -individual or collective- in all its social, political and cultural diversity. An anthropological approach founded on detailed ethnographies of wine production is ideally placed to address economic, social and cultural disruptions caused by the emergence of these new environmental challenges. Indeed, the community of experts in environmental change have recently called for research that will encompass the human dimension and for more broad-based, integrated through interdisciplinarity, useful knowledge (Castree & al 2014). My paper seeks to engage with climate ethnography and discuss what it brings to the study of wine environmental futures while exploring the limitations of the anthropological environmental approach.