IVAS 2022 banner
IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 Asymmetrical flow field-flow fractionation with online multidetection is a viable tool to investigate colored red wine colloids

Asymmetrical flow field-flow fractionation with online multidetection is a viable tool to investigate colored red wine colloids

Abstract

Despite its relevance for wine quality and stability, red wine colloids have not still been sufficiently investigated, an occurrence due to the lack of suitable analytical techniques to study them as they are present in wine. Recently, asymmetrical Flow Field-flow Fractionation (AF4) with online multidetection has been tested as a new analytical tool to this aim, revealing its suitability for quantification, fractionation, and characterization of wine colloids in native state [1]. With the aim to characterize red wines in relation to their colloidal composition, AF4 technique was applied to 24 monovarietal Italian wines kept in bottles for 2 years and produced without any filtration, oak contact, fining treatments, malolactic fermentation or ageing on yeast lees. AF4 analysis allowed to quantify wine colloids, and to characterize them in terms of dimensions (by MALS) and absorbance (A280 & A520 nm). MALS revealed that each wine contained several colloids’ populations of different sizes (from 10 to 130 nm), but most of them showed sizes in the range 20 – 40 nm. The comparison by AF4 analysis of the A280-absorbing species present in whole wines with that of wines containing only species larger than 5 kDa (which were considered as colloids) allowed to calculate for each wine the percentage of molecules involved in the assembly of colloidal particles. This calculation showed that in the different samples the percentage of colloids varied from 1 to 44% of the total A280 absorbing compounds, indicating the diversity of the wines. Given that the A280 signal is mostly due to phenolics and proteins, these data indicate that very different percentages of these compounds participate in the formation of particles in the 20 – 40 nm size range. This means that phenolics necessarily need to be associated with other wine components to form particles of those dimensions. This association should involve proteins and polysaccharides [1]. The A520 data indicated the presence of pigments in the colloidal fraction. These pigments are likely to be constituted of tannin-anthocyanins complexes (polymeric pigments). Therefore, given the absence of species with sizes <20 nm, an association of these colored complexes with other colloidal-forming compounds seems necessary, the obvious candidate being proteins as they are known to strongly interact with tannins. Our results suggest that the color of red wines is due, in addition to free oligomeric pigments, also to colloidal particles formed by these latter bound to proteins, and that the quantity of these particles is highly variable in wines from different origin. How the presence of proteins affects the stability and evolution of red wines’ color remains to be investigated, keeping into consideration also the contribution of wine polysaccharides, which have been previously found to be part of the red wine colloidal particles [1].

References

[1] Marassi, et al. Food Hydrocoll 2021;110:106204.
Acknowledgments: MIUR project PRIN n.20157RN44Y

DOI:

Publication date: June 23, 2022

Issue: IVAS 2022

Type: Article

Authors

Marangon Matteo1, Marassi Valentina2, Roda Barbara2, Zattoni Andrea2, Reschiglian Pierluigi2, Mattivi Fulvio3,4, Moio Luigi5, Parpinello Giuseppina Paola6, Piombino Paola5, Río Segade Susana7, Rolle Luca7, Slaghenaufi Davide8, Versari Andrea6, Vrhovsek Urska4, Ugliano Maurizio8 and Curioni Andrea1

1Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Italy
2Department of Chemistry “G. Ciamician”, University of Bologna, Italy
3Department of Cellular, Computational and Integrative Biology – CIBIO, University of Trento, Italy
4Department of Food Quality and Nutrition, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all’Adige, Italy
5Department of Agricultural Sciences, Division of Vine and Wine Sciences, University of Napoli Federico II, Italy
6Department of Agricultural and Food Sciences, University of Bologna, Italy
7Department of Agricultural, Forest and Food Sciences, University of Torino, Italy
8Department of Biotechnology, University of Verona, Italy

Contact the author

Keywords

red wine, colloids, proteins, polysaccharides, phenolics

Tags

IVAS 2022 | IVES Conference Series

Citation

Related articles…

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.

Biodiversity in the vineyard agroecosystem: exploring systemic approaches

Biodiversity conservation and restoration are essential for guarantee the provision of ecosystem services associated to vineyard agroecosystem such as climate regulation trough carbon sequestration and control of pests and diseases. Most of published research dealing with the complexity of the vineyard agroecosystems emphasizes the necessity of innovative approaches, including the integration of information at different temporal and spatial scales and development of systemic analysis based on modelling. A biodiversity survey was conducted in the Franciacorta wine-growing area (Lombardy, Italy), one of the most important Italian wine-growing regions for sparkling wine production, considering a portion of the territory of 112 ha. The area was divided into several Environmental Units (EUs), defined as a whole vineyard or portion of vineyard homogenous in terms of four agronomic characteristics: planting year, planting density, cultivar, and training system. In each EU a set of compartments was identified and characterised by specific variables. The compartments are meteorology, morphology (altitude, slope, aspect, row orientation, and solar irradiance), ecological infrastructures and management. The landscape surrounding EU was also characterised in terms of land-use in a buffer zone of 500 m. For each component a specific methodology was identified and applied. Different statistical approaches were used to evaluate the method to integrate the information related to different compartments within the EU and related to the buffer zone. These approaches were also preliminarily evaluated for their ability to describe the contribution of biodiversity and landscape components to ecosystem services. This methodological exploration provides useful indication for the development of a fully systemic approach to structural and functional biodiversity in vineyard agroecosystems, contributing to promote a multifunctional perspective for the all wine-growing sector.

Better understand the soil wet bulb formation with subsurface or aerial drip irrigation in viticulture

The gradual change in rainfall patterns experienced in the south of France vineyards, especially around the Mediterranean sea, means that the vines are increasingly subject to summer drought. The winegrowers developped the use of irrigation techniques to ensure the maintenance of competitive yields in the production of wines under Protected Geographical Indication label. In practice, drip irrigation pipes can be installed above the ground or buried into the soil as well as at different distances from the vine row. The objective of this study was to examine the profiles of the wet bulbs of the soil obtained from two drip irrigation systems : aerial drip located under the vine row and subsurface drip placed in the middle of the inter-row. This experiment took place over two consecutive seasons (2020-2021) on a 3.4 ha Viognier plot in the Mediterranean region (PGI Oc, France) on sandy clay soil. The annual rainfalls were less than 400 mm. Soil water content probes were installed at different depths (20 – 40 – 60 – 80 cm) and at different lateralities from the vine row (30 – 60 – 90 – 120 cm) to control the formation of the soil wet bulb during irrigation. The mapping and the analysis of the data allowed a better understanding and differentiation of the water percolation when irrigating with subsurface or aerial drip. For the same amount of water and without differences of vine water status, it is shown that in a subsurface drip irrigation situation, the size of the wet bulb formed is larger than in aerial drip irrigation system.

Mobile device to induce heat-stress on grapevine berries

Studying heat stress response of grapevine berries in the field often relies on weather conditions during the growing season. We constructed a mobile heating device, able to induce controlled heat stress on grapes in vineyards. The heater consisted of six 150 W infrared lamps mounted in a profile frame. Heating power of the lamps could be controlled individually by a control unit consisting of a single board computer and six temperature sensors to reach a pre-set temperature. The heat energy applied to individual berries within a cluster decreases by the squared distance to the heat source, enabling the establishment of temperature profiles within individual clusters. These profiles can be measured by infrared thermography once a steady state has been reached. Radiant flux density received by a berry depending on the distance was calculated based on a view factor and measured lamp surface temperature and resulted to 665 Wm-2 at 7cm. Infrared thermography of the fruit surface was in good agreement with measurements conducted with a thermocouple inserted at epidermis level. In combination with infrared thermography, the presented device offers possibilities for a wide range of applications like phenotyping for heat tolerance in the field to proceed in the understanding of the complex response of plants to heat stress. Sunburn necrosis symptoms were artificially induced with the aid of the device for cv. Bacchus and cv. Sylvaner in the 2020 and 2021 growing season. Threshold temperatures for sunburn induction (LT5030min) were derived from temperature data of single berries and visual sunburn assessment, applying logistic regression. A comparison of threshold temperatures for the occurrence of sunburn necrosis confirmed the higher susceptibility of cv. Bacchus. The lower susceptibility of cv. Sylvaner did not seem to be related to its phenolic composition, rendering a thermoprotective role of berry phenolic compounds unlikely.

Mechanisms involved in the heating of the environment by the aerodynamic action of a wind machine to protect a vineyard against spring frost

One of the main consequences of global warming is the rise of the mean temperature. Thus, the heat summation by the plants begins sooner in the early spring, and by cumulating growing degree-days, phenological development tends to happen earlier. However, spring frost is still a recurrent phenomenon causing serious damages to buds and therefore, threatening the harvests of the winegrowers. The wind machine is a solution to protect fruit crops against spring frost that is increasingly used. It is composed of a 10-m mast with a blowing fan at its peak. By tapping into the strength of the nocturnal thermal inversion, it sweeps the crop by propelling warm air above to the ground. Thus, stratification is momentarily suppressed. Furthermore, the continuous action of the machine, alone or in synergy, or the addition of a heater allow the bud to be bathed in a warmer environment. Also, the punctual action of the tower’s warm gust reaches the bud directly at each rotation period. All these actions allow the bud to continuously warm up, but with different intensities and over a different period. Although there is evidence of the effectiveness of the wind machines, the thermal transfers involved in those mechanisms raise questions about their true nature. Field measurements based on ultrasonic anemometers and fast responding thermocouples complemented by laboratory measurements on a reduced scale model allow to characterize both the airflow produced by the wind machine and the local temperature in its vicinity. Those experiments were realized in the vineyard of Quincy, in the framework of the SICTAG project. In the future paper, we will detail the aeraulic characterization of the wind machine and the thermal effects resulting from it and we will focus on how the wind machine warms up the local atmosphere and enables to reduce the freezing risk.