OENO IVAS 2019 banner
IVES 9 IVES Conference Series 9 Grape seed powder as an alternative to bentonite for wine fining

Grape seed powder as an alternative to bentonite for wine fining

Abstract

PR proteins can cause haze in wines, and the risk is to keep the wine unsold. Generally, in winemaking bentonite solves this problem by removing proteins, but it is not a renewable resource, has poor settling, which means difficulty in filtering after use and a considerable loss of wine, it is not a specific adsorbent and may reduce aromas and flavor compounds. This work studied the use of grape seeds powder (GSP) to remove haze-forming proteins from wine and grape juice. GSP was tried both roasted 180°C x 10 minutes and unroasted, while contact time was set at one hour and two hours for comparison. GSP was tried first on four different heat-unstable wines in small-scale experiments. The results showed that GSP removed PR proteins and permitted to achieve heat stability (DNTU<2) but with high doses (25-32 g/L) of addition. A similar reduction of PR proteins was obtained in all the wines after 1-h contact time with unroasted GSP as wells as with roasted GSP, which suggests that roasting did not substantially alter the protein-binding capability of GSP. Contact time (1 or 2 hours) did not change the efficacy of protein removal suggesting that the reaction between grape tannins and proteins occurs within one hour. Treated wines showed changes in the matrix composition, with increased phenolic contents (A280) and improved yellow color (CIELAB b* parameter). As for the experiments with grape juice, GSP was added in two juices before fermentation to observe the impact on the composition of the finished wines. Roasted GSP was chosen as the fining agent and the contact time was 1 hour. A lower amount of GSP (5 g/L) was observed to be needed to heat-stabilize (DNTU<2) the juices. The corresponding wines showed minor changes in the matrix composition, perhaps because of phenolic-protein interaction and precipitation during the fermentation or degradation via non-enzymatic processes. These results suggested that GSP may be a viable alternative to bentonite. Furthermore, being a by-product of winemaking, GSP utilization would improve the environmental sustainability of winemaking processes.

DOI:

Publication date: June 10, 2020

Issue: OENO IVAS 2019

Type: Article

Authors

Elia Romanini, Jacqui M. McRae, Donato Colangelo, Milena Lambri

The Australian Wine Research Institute, Waite Precinct, Hartley Grove cnr Paratoo Road, Urrbrae (Adelaide), PO Box 197, Glen Osmond, SA 5064, Australia.
UniversitàCattolica del Sacro Cuore – DiSTAS Via Emilia Parmense, 84, 29122 Piacenza, Italy.

Contact the author

Keywords

grape seeds, bentonite, fining, hazing proteins 

Tags

IVES Conference Series | OENO IVAS 2019

Citation

Related articles…

Exploring intra-vineyard variability with sensor- and molecular-based approaches 

The application of remote and proximal sensing is a fast and efficient method to monitor grapevine vegetative and physiological parameters and is considered valuable to derive information on associated yield and quality traits in the vineyard. Further details can be obtained by the application of molecular analysis at the gene expression level aiming at elucidating how pathways controlling the formation of different grape quality traits are influenced by spatial variability. This work aims at evaluating intra-vineyard variability in grape composition at harvest and at comparing this with remotely sensed canopy vegetation data and molecular-based approaches.

Simulating climate change impact on viticultural systems in historical and emergent vineyards

Global climate change affects regional climates and hold implications for wine growing regions worldwide. Although winegrowers are constantly adapting to internal and external factors, it seems relevant to develop tools, which will allow them to better define actual and future agro-climatic potentials. Within this context, we develop a modelling approach, able to simulate the impact of environmental conditions and constraints on vine behaviour and to highlight potential adaptation strategies according to different climate change scenarios. Our modeling approach, named SEVE (Simulating Environmental impacts on Viticultural Ecosystems), provides a generic modeling framework for simulating grapevine growth and berry ripening under different conditions and constraints (slope, aspect, soil type, climate variability…) as well as production strategies and adaptation rules according to climate change scenarios. Each activity is represented by an autonomous agent able to react and adapt its reaction to the variability of environmental constraints. Using this model, we have recently analyzed the evolution of vineyards’ exposure to climatic risks (frost, pathogen risk, heat wave) and the adaptation strategies potentially implemented by the winegrowers. This approach, implemented for two climate change scenarios, has been initiated in France on traditional (Loire Valley) and emerging (Brittany) vineyards. The objective is to identify the time horizons of adaptations and new opportunities in these two regions. Carried out in collaboration with wine growers, this approach aims to better understand the variability of climate change impacts at local scale in the medium and long term.

Pinot noir: an endemic or a flexible variety?

Pinot noir has its historical roots in Burgundy and is generally considered as an endemic vine variety which means that its adaptation is very specific to this environment

Climate influence on the grapevine phenology and anthocyanins content in wines from the Skopje vineyard area, Republic of Macedonia

The phenological stages and the content of the anthocyanins of non-irrigated cultivars Blatina, Vranec, Kratoshija, Prokupec and Stanushina were study

Grape ripening delaying with combined use of leaf removal and natural shading in Manto negro (Vitis vinifera L.) under deficit irrigation

The increasing frequency of heat waves during grape ripening presents challenges for the production of high-quality wine grapes. This underscores the significance of developing effective irrigation and canopy management techniques to optimize both yield and grape quality.
A field experiment was carried out during 2021 and 2022 using Manto negro wine grapes to study the effect of two irrigation strategies and different light exposure levels on grape quality. In a four-block experimental vineyard at Bodega Ribas in Mallorca, two irrigation treatments—moderate and severe deficit irrigation—were implemented. Within each irrigation plot, three light exposure treatments were randomly assigned, encompassing exposed clusters from pea size, non-exposed clusters, and shaded clusters after softening.