IVAS 2022 banner
IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 Assyrtiko wines of Santorini produced by different autochthonous yeasts: Differences in aromatic and organoleptic profiles

Assyrtiko wines of Santorini produced by different autochthonous yeasts: Differences in aromatic and organoleptic profiles

Abstract

Different yeasts were isolated from spontaneous fermentation of Assyrtiko grape must in Santorini Island, Greece. Molecular typing revealed the presence of three Saccharomyces cerevisiae strains (S9, S13, S24) and one strain of the yeast species Nakazawaea ishiwadae (N.i). The four isolated strains were further tested in laboratory scale fermentations of Assyrtiko must in pure inoculation cultures and in sequential inoculation (72 hours) of each S. cerevisiae strain with the strain of N. ishiwadae. All fermentation trials were realised in duplicate.

 Fermentation kinetics were followed by HPLC, while the volatile composition of the final products was determined by GC-MS (qualitative analysis) and GC-FID (quantitative analysis). Sensory evaluation of the samples took place by a panel of 10 trained panellists. In general, the fermentation rate in trials with S.13 and N.i. was lower than the rest, while trials with S9 and S24 resulted in higher ethanol contents in the final product but without statistically important differences. The wines fermented with the S24 and N.i. strains were characterised by the highest concentrations of acetic acid (0.9 and 0.7 g/L respectively) and with S13 by the highest concentration of glycerol (15g/L). In terms of aromatic profile, the trials contacted with S9 were up to 3.5-folds richer in volatile compounds responsible for the fruity character in wines. In addition, the fermentations with S13 and N.i. were about 3-folds richer in compounds characterized by floral character (e.g. phenethyl alcohol, tyrosol etc.), while the most abundant group of compounds in fermentations contacted with S24 strain were the oxidation esters (e.g. ethyl hydrogen succinate). In the sequential inoculations apart from a delay in the completion of alcoholic fermentations, a comparable with single strains fermentations trend in ethanol production and reducing sugar consumption was observed. Intensification of the production of acetic acid, oxidation esters, several ethyl esters and higher alcohols (C5, C6) was also observed. Significantly lower (5-fold) contents of higher alcohols and their corresponding esters, responsible for floral aromas for ferments with N13 compared to ferments with S13 was also noted. Regarding the production of esters responsible for tropical and citrus aromas (e.g. isoamyl acetate, ethyl hexanoate), the highest content was observed in ferments with N13 (1.32 ppm) and N24 (1.97 ppm) while the lowest in ferments with N9 (0.99 ppm). The concentration of most esters was increased for all trials after sequential inoculation compared to the corresponding trials contacted with pure cultures.  The results from the organoleptic analysis are in line with the chemical analysis. Even though, all four newly isolated strains have the ability to ferment and produce dry wines, the most preferred wines by the panel were those produced by S9 and S13 strains.

DOI:

Publication date: June 27, 2022

Issue: IVAS 2022

Type: Poster

Authors

Kallithraka Stamatina1, Christofi Stefania1, Dimopoulou Maria1, Tsapou Evangelia Anastasia1 and Papanikolaou Seraphim1

1Department of Food Science and Human Nutrition, Laboratory of enology and alcoholic drinks, Agricultural University of Athens 

Contact the author

Keywords

Saccharomyces cerevisiae, Nakazawaea ishiwadae, wine volatile content, sensory analysis, fermentation kinetics

Tags

IVAS 2022 | IVES Conference Series

Citation

Related articles…

Impact of climate change on the viticultural climate of the Protected Designation of Origin “Jumilla” (SE Spain)

Protected Designation of Origin “Jumilla” (PDO Jumilla) is located in the Spanish provinces of Albacete and Murcia, in the South-eastern part of the Iberian Peninsula, where most of the models predict a severe impact of climate change in next decades. PDO Jumilla covers an area of 247,054 hectares, of which more than 22,000 hectares

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.

Modeling the suitability of Pinot Noir in Oregon’s Willamette Valley in a changing climate

Air temperature is the key driver of grapevine phenology and a significant environmental factor impacting yield and quality for a winegrape growing region. In this study the optimal downscaled CMIP5 ensemble for computing thegrowing season average temperature (GST) viticulture climate classification index was determined to spatially compute on a decadal basis predictions of the GST climate index and the grapevine sugar ripeness (GSR) model for Pinot Noir throughout the Willamette Valley (WV) American Viticultural Area (AVA). Forecasts for average temperature and a 220 g/L target sugar concentration level were computed using daily Localized Constructed Analogs (LOCA) downscaled CMIP5 historic and Representative Concentration Pathways (RCP) future climate projections of minimum and maximum daily temperature. We explore spatiotemporal trends of the GST climate classification index and Pinot Noir specific applications of the GSR phenology model for the WV AVA. Spatiotemporal computations of the GST climate index and Pinot Noir specific applications of the GSR model enable the opportunity to explore relationships between their computed values with one intent being to provide updated GST ranges that better align with current temperature-based modeling understanding of Pinot Noir grapevine phenology and the viticultural application of LOCA CMIP5 climate projections for the WV AVA. The Pinot Noir specific applications of the GSR model or the GST index with updated bounds indicate that the percent of the WV AVA area suitable for Pinot Noir production is currently at or near its peak value in the upper 80s to lower 90s of this century.

Different soil types and relief influence the quality of Merlot grapes in a relatively small area in the Vipava Valley (Slovenia) in relation to the vine water status

Besides location and microclimatic conditions, soil plays an important role in the quality of grapes and wine. Soil properties influence…

The potential of multispectral/hyperspectral technologies for early detection of “flavescence dorée” in a Portuguese vineyard

“Flavescence dorée” (FD) is a grapevine quarantine disease associated with phytoplasmas and transmitted to healthy plants by insect vectors, mainly Scaphoideus titanus. Infected plants usually develop symptoms of stunted growth, unripe cane wood, leaf rolling, leaf yellowing or reddening, and shrivelled berries. Since plants can remain symptomless up to four years, they may act as reservoirs of FD contributing to the spread of the disease. So far, conventional management strategies rely mainly on the insecticide treatments, uprooting of infected plants and use of phytoplasma-free propagation material. However, these strategies are costly and could have undesirable environmental impacts. Thus, the development of sustainable and noninvasive approaches for early detection of FD and its management are of great importance to reduce disease spread and select the best cultural practices and treatments. The present study aimed to evaluate if multispectral/hyperspectral technologies can be used to detect FD before the appearance of the first symptoms and if infected grapevines display a spectral imaging fingerprint. To that end, physiological parameters (leaf area, chlorophyll content and photosynthetic rate) were collected in concomitance to the measurements of plant reflectance (using both a portable apparatus and a remote sensing drone). Measurements were performed in two leaves of 8 healthy and 8 FD-infected grapevines, at four timepoints: before the development of disease symptoms (21st June); and after symptoms appearance (ii) at veraison (2nd August); at post-veraison (11th September); and at harvest (25th September). At all timepoints, FD infected plants revealed a significant decrease in the studied physiological parameters, with a positive correlation with drone imaging data and portable apparatus analyses. Moreover, spectra of either drone imaging and portable apparatus showed clear differences between healthy and FD-infected grapevines, validating multispectral/ hyperspectral technology as a potential tool for the early detection of FD or other grapevine-associated diseases.