 IVES 9 IVES Conference Series 9 Effect of environmentally friendly vineyard protection strategies on yeast ecology during fermentation

Effect of environmentally friendly vineyard protection strategies on yeast ecology during fermentation

Abstract

AIM: Currently, an increasing concern from governments and consumers about environmental sustainability of wine production provides new challenges for innovation in wine industry. Accordingly, the application of more-environmentally friendly vineyard treatments against fungal diseases (powdery and downy mildew) could have a cascading impact on yeast ecology of wine production.

METHODS: This study evaluated the effect of a wide range of environmentally friendly products applied in the vineyard on grape yeast ecology at harvest, as well as during spontaneous and inoculated fermentations in winery and laboratory scale conditions. Yeast ecology was investigated using culture-dependent (plate counts) and -independent (Next Generation Sequencing) methods. Main oenological parameters and volatile compounds were monitored during spontaneous and inoculated fermentations. Spearman’s correlation was used to assess associations between ASVs changes and chemical composition observed over fermentation.

RESULTS: No significant differences were observed among the alternative and conventional treatments, compared to the controls, in terms of yeast population and biodiversity. The only exception was the increased population levels of Auerobasidium pullulans as response to three alternative treatments. This increase can positively affect the quality and the safety of the grapes, since A. pullulans is considered a biocontrol agent of pathogens. Overall, wine composition was greatly influenced by the inoculation, rather than the type of treatment applied previously in the vineyard. Fermentation data suggested that complete alcoholic fermentation was positively correlated to the application of antifungal treatment in the vineyard and the inoculation protocol used. Spontaneous fermentations conducted in laboratory using grapes previously treated with laminarin showed a higher relative frequency of Saccharomyces cerevisiae than other treatments, and its corresponding fermentation led to compounds responsible for floral and fruity scents without increasing the levels of the acetic acid.

CONCLUSIONS:

Yeast ecology in fermenting musts may be correlated to specific antifungal products and inoculation protocol employed, suggesting a link between principal active compounds, yeast biodiversity and wine chemical composition. These relationships could help to further control wine quality and improve consumer acceptance and economic value of wines.

DOI:

Publication date: September 3, 2021

Issue: Macrowine 2021

Type: Article

Authors

Vasileios Englezo, Vasileios ENGLEZOS, Ilario FERROCINO, Simone GIACOSA, Susana RIO SEGADE, Jatziri MOTA-GUTIERREZ, Luca COCOLIN, Luca ROLLE, Kalliopi RANTSIOU

University of Turin, DISAFA, Italy, University of Turin, DISAFA, Italy

Contact the author

Citation

The modification of cultural practices in grapevine cv. Syrah, does it modify the characteristics of the musts?

The work shows the results of a year of experimentation (2020) in a Syrah variety vineyard in La Roda (Castilla-La Mancha, Spain). The trial approach was on a randomized block design with two factors: Irrigation (I) and Pruning (P).
Irrigation schedules were adjusted to apply amounts close to 1,500 m3/ha. With this provision, 2 different irrigation treatments were proposed: I1) Start of irrigation from pea-sized grape to post-harvest (providing at least 20 % of the total amount of irrigation water to be provided post-harvest); I2) Start of irrigation from pea-sized grape to harvest (usual irrigation practice in the study area). Pruning was proposed with two treatments, one at the end of January (P1), which is pruning on a conventional date; and P2) pruning carried out at the beginning of budding. In total, 4 repetitions were designed with 4 elementary plots, each one of them representing one of the proposed treatments (I1P1; I1P2; I2P1; I2P2). In total, 16 plots were worked on and each elementary plot consisted of 30 strains, distributed in 3 lines.
The productive response was evaluated with the yield results of the harvest harvested at 23 ºBrix. The qualitative response was measured in the musts through the indices of technological (acidity, pH and potassium) and phenolic maturity and aromatic compounds in free and glycosylated fractions. The treatments tested had, in general, an effect on the different variables analyzed.

Impact of climate variability and change on grape yield in Italy

Viticulture is entangled with weather and climate. Therefore, areas currently suitable for grape production can be challenged by climate change. Winegrowers in Italy already experiences the effect of climate change, especially in the form of warmer growing season, more frequent drought periods, and increased frequency of weather extremes.
The aim of this study is to investigate the impact of climate variability and change on grape yield in Italy to provide winegrowers the information needed to make their business more sustainable and resilient to climate change. We computed a specific range of bioclimatic indices, selected by the International Organisation of Vine and Wine (OIV), and correlated them to grape yield data. We have worked in collaboration with some wine consortiums in northern and central Italy, which provided grape yield data for our analysis.
Using climate variables from the E-OBS dataset we investigate how the bioclimatic indices changed in the past, and the impact of this change on grape productivity in the study areas. The climate impact on productivity is also investigated by using high-resolution convection-permitting models (CPMs – 2.2 horizontal resolution), with the purpose of estimating productivity in future emission scenarios. The CPMs are likely the best available option for this kind of impact studies since they allow a better representation of small-scale processes and features, explicitly resolve deep convection, and show an improved representation of extremes. In our study, we also compare CPMs with regional climate models (RCMs – 12 km horizontal resolution) to assess the added value of high-resolution models for impact studies. Further development of our study will lead to assessing the future suitability for vine cultivation and could lead to the construction of a statistical model for future projection of grape yield.

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Local adaptation tools to ensure the viticultural sustainability in a changing climate

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