Macrowine 2021
IVES 9 IVES Conference Series 9 Response of different nitrogen supplementation on Saccharomyces cerevisiae metabolic response and wine aromatic profile

Response of different nitrogen supplementation on Saccharomyces cerevisiae metabolic response and wine aromatic profile

Abstract

The wine yeast Saccharomyces cerevisiae can highly affect wine aromatic profile by producing and/or mediating the release of a whole range of metabolites (such as thiols, esters, and terpenes), which in turn contribute to enhanced aroma and flavor. These metabolites depend on yeast metabolism activated during fermentation which can constitute the ‘’metabolic footprint’’ of the yeast strain that carried out the process. The aim of the present research was to study the metabolism of S. cerevisiae under two different nitrogen supplementation status and to investigate the relative expression of specific genes, that are directly related to the biosynthesis of specific potent odornats such as, terpenes and esters. 

The commercial yeast strains 1X (S.cerevisiae) and 2X (S.cerevisiae x S.bayanus) were inoculated in Moschofilero (Vitis Vinifera L. cv) grape must under two different concentrations of yeast assimilable nitrogen (YAN), a  low at 150 mg/L and a high at 300 mg/L. The produced wines were analyzed for their standard enological parameters, their volatile composition by SPE/GC–MS analysis as well as for their sensory profile. Totally 8 fermentations trials, were realised in triplicate. The fermentation was monitored by measuring the optical density and sugar consumption. Metabolic response was tested through real-time RT-PCR of genes implicated in aroma production of esters and terpenes such as ATF1, ATF2, EEB1, EHT1, IAH1, BGL2, EXG1. Sampling for metabolites and gene expression analysis were taken at the time of inoculation, after 48 hours, when two thirds of the sugars were depleted and at the end of the alcoholic fermentation (< 2g/L rs).

In terms of the volatile characterization of the wines, esters, linalool and nerol appeared to be clearly distinct between the different levels of YAN, which confirms the specialization in volatile compounds production among different nitrogen concentration levels. For instance, linalool was found to be at 0.05 mg/L for low nitrogen concentration, while high nitrogen levels resulted to a concentration of 0.12 mg/L. Real-time-PCR results revealed that, in both cases of nitrogen implementation, the analyzed genes were found to be expressed mainly before the fermentation of the 70% of the sugars. In addition, an overexpression of the BGL2 gene, corresponded well to the linalool concentration found, was observed in case of high nitrogen condition. Also, the EHT1 was expressed five times higher in case of high nitrogen concentration. Finally, correlations between ethyl esters and EEB1, acetate esters and ATF2 (p<0.05) were also found in both cases. 

Our study revealed the impact of different nitrogen implementations on the volatile compounds and the relative expression of specific genes. Metabolic analysis of selected volatile components of the wine aroma in conjunction with transcriptional analyses provide a great approach to orient the fermentation process towards a desirable wine aromatic profile.

DOI:

Publication date: September 3, 2021

Issue: Macrowine 2021

Type: Article

Authors

Despina Lola, Chrysanthi KALLONIATI, Maria DIMOPOULOU, Maria Ioanna XENIA, Emmanouil FLEMETAKIS, Yorgos KOTSERIDIS

Laboratory of Oenology and Alcoholic Drinks (LEAD), Agricultural University of Athens, 75 Iera Odos, 11855 Athens, Greece, Laboratory of Molecular Biology, Agricultural University of Athens, 75 Iera Odos, 11855 Athens, Greece, Department of Wine, Vine and Beverage Sciences, School of Food Science, University of West Attica, Greece, Laboratory of Oenology and Alcoholic Drinks  (LEAD), Agricultural University of Athens, 75 Iera Odos, 11855 Athens, Greece Laboratory of Molecular Biology, Agricultural University of Athens, 75 Iera Odos, 11855 Athens, Greece, Laboratory of Enology and Alcoholic Drinks (LEAD), Agricultural University of Athens, 75 Iera Odos, 11855 Athens, Greece

Contact the author

Keywords

yeast metabolism, yan, nitrogen supplementation, volatile profile, gene expression

Citation

Related articles…

A versatile genome editing platform for grapevine: improving biotic and abiotic stress resilience 

New Plant Breeding Techniques (NPBTs) have arisen with the objective of surmounting the constraints inherent in conventional breeding methodologies, thereby enhancing plant resilience against both biotic and abiotic stresses. To date the application of genome editing in grapevine is still limited by the necessity to overcome recalcitrance to produce embryogenic calli and to regenerate plants. In our studies, we developed a smart and versatile genetic transformation system carrying all the most promising features of different genome editing approaches. In specific, we joined the GRF-GIF expression to improve regeneration, the systemic movement of the editing transcripts through tRNA-like sequences (TLS) and the cisgenic-like approach to remove transgenes.

Rapid damage assessment and grapevine recovery after fire

There is increasing scientific consensus that climate changeis the underlying cause of the prolonged dry and hot conditions that have increased the risk of extreme fire weather in many countries around the world. In December 2019, a bushfire event occurred in the Adelaide Hills, South Australia where 25,000 hectares were burnt and in vineyards and surrounding areas various degrees of scorching and infrastructure damage occurred. The ability to coordinate and plan recovery after a fire event relies on robust and timely data. The current practice for measuring the scale and distribution of fire damage is to walk or drive the vineyard and score individual vines based on visual observation. The process is time consuming, subjective, or semi-quantitative at best. After the December 2019 fires, it took many months to access properties and estimate the area of vineyard damaged. This study compares the rapid assessment and mapping of fire damage using high-resolution satellite imagery with more traditional ground based measures. Satellite imagery tracking vineyard recovery in the season following the bushfire is being correlated to field assessments of vineyard productivity such as canopy health and development, fertility and carbohydrate storage. Canopy health in the seasons following the fires correlated to the severity of the initial fire damage. Severely damaged vines had reduced canopy growth, were infertile or had very low fertility as well as lower carbohydrate levels in buds and canes during dormancy, which reduced productivity in the seasons following the bushfire event. In contrast, vines that received minor damage were able to recover within 1-2 years. Tools that rapidly and affordably capture the extent and severity of damage over large vineyard area will allow producers, government and industry bodies to manage decisions in relation to fire recovery planning, coordination and delivery, improving the efficiency and effectiveness of their response.

Use of fumaric acid on must or during alcoholic fermentation

Fumaric acid has been approved by the OIV in 2021 for its application on wine to control the growth and activity of lactic acid bacteria. Fumaric acid is currently being evaluated by the OIV as an acidifier of must and wine. Investigations during the 2023 vintage provided further information on its use on must or during AF, thus completing information provided during the previous vintage.

OPTIMIZING THE IDENTIFICATION OF NEW THIOLS AT TRACE LEVEL IN AGED RED WINES USING NEW OAK WOOD FUNCTIONALISATION STRATEGY

During bottle aging, many thiol compounds are involved in the expression of bouquet of great aged red wines according to the quality of the closure.1,2 Identifying thiol compounds in red wines is a challenging task due several drawbacks including, the complexity of the matrix, the low concentration of these impact compounds and the amount of wine needed.3,4
This work aims to develop a new strategy based on the functionalisation of oak wood organic extracts with H₂S, to produce new thiols, in order to mimic what can happen in red wine during bottle aging. Following this approach and through sensory analysis experiments, we demonstrated that the vanilla-like aroma of fresh oak wood was transformed into intense “meaty” nuances similar to those found in old but non oxidized red wines.

Perceptive interactions and wine typical fruity aroma 

In this study we developed a methodology to prepare aromatic reconstitutions from fractions of a wine organic extract and we assessed these reconstitutions both in wine model solution and in de- aromatized wine.